Warning Do not get a qualification with ICS Learn in the UK (BTEC L3) - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 05:38:14 pm
content: Hello everyone and you may remember a while ago I was complaining about my BTEC level III course in electronic engineering. After a lot of arguments they have mostly refunded my employer. Basically because I became such a thorn in their side that they did not want me to have access to their forum any longer where I was leading the discussion on how bad the course is.The BTEC level III course in electronic engineering as provided by ICS learn is of extremely poor quality. If you really want to learn then I would not recommend it at all. The explanations in the course are so woolly that they serve no practical purpose whatsoever. While some will be pleased with minimum amount of math this course is so minimal in maths that it is pointless doing. Add to that many technical errors in the course. For example they could not even print the correct pin out for a 741 operational amplifier and managed to invert the power pins obviously a very deadly error for the chip supplied in the kit.I did actually come up with almost 3 A4 pages of comments and corrections but they decided that they had an internal "subject matter expert" who knew better than me. Funny that at because despite my continuing asking to speak to this person and to be put right if I was really wrong, they never materialised even at the end of a phone line. I was told I will be contacted by a tutor to put me right instead but the cheetahs were very slow to get in touch. It's in fact took nearly 2 months for a tutor to get in touch and once they did start getting in touch it was to tell me they agreed with me.Once I came to try and do the assignment which is the thing based on which I would be given a qualification I found it to be so full of errors that it could not be completed. The questions were also asking for a level of skill beyond that explained in the course material, therefore could not be completed anyway by somebody had studied the course from scratch and nothing else. Then there were errors in the diagrams given in the assignment therefore again the assignment cannot be completed.The assignment can be found here:www.sparkylabs.co.uk/Assignment1.pdfI have spent at least two months dealing with ICS learn and Pearson who run the qualification board EDEXCEL and frankly considering the gravity of the mistakes they don't seem to be taking things very seriously and just seem to be giving me the runaround. It seems that education in the UK is run by a bunch of companies who self certify themselves. Pearson cannot give me a deadline as to when they will complete their investigation. To illustrate how short their investigation should be the assignment they need to check out is linked above, be your own judge of the incompetence and level of fraud that ICS learn is committing. Because if anybody was given a certificate based on trying to resolve this assignment they were either well beyond the skill level that the course on its own would teach or they were simply handed a certificate in exchange for money.The course material author continually refers readers to the Internet. Sources such as Wikipedia, University pages and even some Joe Bloggs hobby website are cited as further reading where the student can read exactly the same material again or rather the same concepts explained but explained properly unlike they are in the course material paid for.To this date I'm still waiting for this course to be taken off the market. It is still as far as I know for sale. So be warned, there are very very few distance learning providers who will do electronic qualifications. In fact I believe that ICS learn are the only ones who will do a level III. The only other course available by distance learning is a HNC and there are few of these as well. It is a sad state of affairs for this country (the UK) but sadly this is what you get from privatisation and a political class who do not really care for education.I have even tried to contact the government overseeing body who are asking me to allow Pearson to complete their investigation before they will do anything, despite the fact I have explained that this course amounts to fraud. Like I say the assignment is attached be your own judges.Below is a video I did in response to one of the questions which asked for a video to be made of me building a circuit and of the circuit working. I have previously posted this video and it shows me describing what will happen to one of the circuits in the assignment and how it will go wrong and why. And it shows just that happening. So they can't say I'm doolally. I have sent a copy of this video to ICS learn and I'm still awaiting a response from their "subject matter expert" which they promised I would get.After I posted this video on the ICS learn forum the administrator of the course tried to tell us that the question was something else and even somebody else pointed out to her before me that this was not the case at all and that the question was very specific and did ask for a video of the circuit being built and operated. She tried to maintain that we were only supposed to explain the working of the transistor in the circuit.http://youtu.be/fLq7-GzbGG0

author: cjo20
author_rank: Contributor
timestamp: July 27, 2014, 06:46:32 pm
content: Your complaint at the start of the video is that they haven't given component values for the FET circuit or provided the FET (I've only watched the first couple of minutes). That is because the assignment isn't asking you to build that circuit. I think that the problem you have boils down to a bad indentation on the "Video" heading. It never states you have to build the FET circuit, only explain its operation.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 06:52:10 pm
content: Well they definitely ask for a video of something, if they can't write a proper structured assignment that is not my problem:Record a video of your circuit being built. You must be in the video.Record a video of your circuit in operation and the measurements being taken. You mustbe in the video.Fact is that is not a valid amplifier circuit, it may be used as the initial explanation but should not be used in an assignment. Have you noticed the earlier questions where a 10K pot is supposed to act as a variable voltage supply to a 1K load ?, the same error occurs later, we shall leave aside that the pot provided like may other mechanical parts supplied never even fitted the breadboard.

author: IanB
author_rank: Super Contributor
timestamp: July 27, 2014, 06:54:52 pm
content: IMHO you may perhaps be falling into an unhappy gap between educational opportunities.At one end you have the electrical trade and trade qualifications as an electrician (done by hands on courses at a trade college).At the other end you have the electrical/electronic engineering professions (entered with a university degree, BSc, BEng or MEng).In the middle you have electrical/electronics technicians.This latter option was always traditionally entered by employer sponsored courses at a college of further education, either on day release, evening study, or both. I have friends and family who took this path in the 80's, for example with MK Electric or British Telecom.I think the unhappy gap you have is the lack of committed employer sponsorship.Distance learning is a new thing, enabled primarily by the internet. In the old days they would have to send you course materials in the mail and you would have to send the answers back. Now they can do it online, but perhaps the system hasn't really caught up with this.I don't quite know what the answer is here.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:01:11 pm
content: @ IanUnfortunately this is as much as I could get by employer sponsorship. The course materials that is two ring binders a textbook and a box of components were physically mailed to me. I do have the option or rather did when I was on the course, uploading files of no more than 10 MB or I'm sure they would have had no objection to meet mailing a paper copy back to them. I did in fact mail a DVD with my video which they said there "subject matter expert" would respond to but I never got said answer. I keep asking about this "subject matter expert" but I'm yet to have any evidence that this person exists and in my opinion it is something they made up on the spot to try and sound official and put me off.I did suggest I go to a local college on day release but my employer does not want this. Apparently we are too busy and it would be unfair to somebody else who was doing an open University degree.The new plan is to go for a distance learning HNC with Teeside University which I can obtain support for for up to 5 years and they say that some people have completed the course in two or three years.

author: IanB
author_rank: Super Contributor
timestamp: July 27, 2014, 07:11:51 pm
content: Having read the assignment I have to agree with cjo20 that you are in no way requested to construct that circuit. If there were any doubt, the fact that they have not given numerical component values, nor supplied the FET, should make it very clear, don't you think?I'm afraid I'm going to have to come back at you with the old saying, "too clever by half".There is an aspect of learning which involves reading comprehension and carefully following instructions. A student can come to grief in this area even if they believe they know the technical content.I know you probably don't want to hear this, but you will achieve greater success in your future learning if you can overcome the temptation to think that you already know the answers. Even if you may do, your knowledge may still be insufficient or incomplete and there may still be more to learn. It's the hardest thing to sit back and recognize that maybe, just maybe, you don't quite know what you think you know.

author: Precipice
author_rank: Frequent Contributor
timestamp: July 27, 2014, 07:12:24 pm
content: Quote from: Simon on July 27, 2014, 06:52:10 pmWell, it sort of is your problem. You're a lot more distressed by it than they are, by the look of it?Quote from: Simon on July 27, 2014, 06:52:10 pmYou notice these things - yay! They ask you describe the operation of the circuit - do so. Explain how you'd fix the shortcomings. Ace the test...(Bear in mind that the source impedance of a 10k pot is very rarely, if ever 10K - discuss...)If your employer asked you to fit a pot to a breadboard, would you have grumbled in the same way?

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:17:43 pm
content: Well you haven't seen the course material of course, this was riddled with errors or so poorly explained that I could see what the author was on about but it was clear that anyone studying from scratch would struggle to comprehend the principles.I sent them a list of comments and I sent the list to my tutor who actually wrote back and said that he agreed with my comments.No I wouldn't try and stick a pot in a breadboard just because my employer asks for it if it was not designed For such use. Now you could say, why didn't I solder some wires to it. Well I will tell you why, because the course tells me all about how great bread boards are and that the great advantage is that I don't need to solder and that I could burn myself if I tried to solder. As you say Ian I shouldn't be too far ahead of myself should I now?@ Ian the whole point of this course was in fact to ensure that I came up to a level III which seems to be the starting point. I was hoping in fact that I would learn something from this course and fill in any holes. Instead given the poor quality of explanations and the dire errors I found in what I do already know I would not want to continue studying from this course with a view to learn anything as if it is not something I don't know already I cannot trust the material, it is that bad.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:22:41 pm
content: Even if we want to consider that I may have missed read the assignment which is entirely possible, can somebody explain then what the video was supposed to be of?

author: cjo20
author_rank: Contributor
timestamp: July 27, 2014, 07:25:23 pm
content: Quote from: Simon on July 27, 2014, 07:22:41 pmThe circuits they actually asked you to build / measure. Read it again with the "Video" section at the same level of indentation as "Context" and "Circuit build".

author: IanB
author_rank: Super Contributor
timestamp: July 27, 2014, 07:27:12 pm
content: I'm not sure how productive it will be to continue this discussion, given what I remember from previous threads on the subject.You have given us one example of course material to look at, the "Assignment1" document. It seems to be very clearly laid out with very comprehensive instructions and full details of what you have to do. If only some of the tests I have seen were that clear!Let me also suggest that many of us here would feel quite able to work through the whole course and readily gain a pass on all the tests. If you are so confident in your knowledge, why are you not simply acing the tests and getting a merit or distinction grade, instead of complaining and raising problems?I'm not sure what your goals are here? Are you trying to further your own career, or trying to do a charitable work by helping all your fellow students?

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:31:22 pm
content: Well bearing in mind that we are talking about a printed paper course which the PDF is a scan of are you trying to say that they are referring to a previous circuit. Isn't this a bit over thought?Can you truly call that diagram an amplifier. Please bear in mind that the course material merely shows a diagram of an amplifier and just about explained how it works in the case of a BJ T the FET amplifier is not even explained. Fact is it is relatively obvious that whoever wrote the whole course lives in their own world and only they know what they mean. We are talking about a very low level of study therefore you would think things will be made relatively clear.Do bear in mind that this course is available for sale around the world and in fact there were foreign students having extreme difficulty just working out what the format was.

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 07:33:01 pm
content: I stayed off the previous version of this thread (the SME thread) but I'll make a few comments on this one...Looking at the transistor circuit in question 1c, it is presumably an N channel DMode FET as drawn. I think it 'will' work as a (reasonably linear) small signal buffer amplifier. eg it could typically be used to interface a hi Z source to a low Z load for very small signals. But it is a very curious choice of MOSFET for a basic course in electronics as these devices are not used as commonly as other types of MOSFET.Maybe it was chosen because it makes the circuit analysis easier? Did they provide a datasheet for the device?

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:41:32 pm
content: Quote from: IanB on July 27, 2014, 07:27:12 pmAs I said you have not seen the actual course which is so poorly explained everybody on the forum was struggling to grasp it which you can see if you go and look at the PDF I have attached. Yes I am being somewhat charitable to my fellow students, I got fed up of my time being wasted too. As I explained earlier because what material I was already knowledgeable in was so badly presented I became concerned that if I did need to learn from material further on I would actually not understand it myself or end up being taught the wrong thing.It did become exceedingly clear that the level of knowledge is not really sufficient to be of any use to me or my employer. And despite the level of knowledge presented is so basic it was a very badly presented to a degree which made simple things hard to understand for other students. I don't do a course just to get a piece of paper I do it to further my own knowledge, of course the piece of paper is useful for my boss.The course does not explain very much about resistance because at the beginning it explains you to be already competent in and understanding of the basic electronic components. However the blurb advertising the course does not state that you need any prior knowledge at all in fact it says that you don't need any prior knowledge therefore something as basic as a 10 K pot trying to feed a 1K load is going to go over the head of most students on this course.The idea was yes that I sort of further my career. I am working for a mechanical company who find they need evermore Electronics to be integrated into their equipment. I have been instrumental in designing a few circuits to solve a few problems and my employer realised that subcontracting things out does not always work because he need somebody in-house to fix problems and to design small things but don't warrant going to a subcontractor which is also much faster. Therefore he thought it wise for the companies benefit and in a way for me who he knows has a passion for Electronics to help me get some qualifications. Unfortunately a BTEC level III is not much use when you are designing safety critical equipment.Again I ask which circuit was I supposed to build in the video. The course administrator could not tell us which one it is so it's still a mystery.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:44:24 pm
content: Quote from: G0HZU on July 27, 2014, 07:33:01 pmYou see you are making all of my points. Only a MOSFET and a J FET was explained. They were explained in a very basic way. A datasheet was never given for any device more was one ever referred to. Your expectations in fact go way way above what this course delivered or seemed to ever intend to deliver. I worked on the assumption it was a MOSFET which as far as I know because I admit I'm not perfect which was the whole reason for starting this course is the most popular FET around. The symbol used also matches the MOSFET symbol given in the course itself so I think my conclusion was fairly obvious and justified in using a MOSFET. No FET device at all was supplied in the kit or even listed in the parts list.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:52:28 pm
content: Of course let us not forget by tutor was supposed to contact me and "put me right" I wrote him an extensive email explaining my concerns and never got a reply this was about the assignment. I send comments to the other tutor as at this point they were now to where as before I could not get hold of anybody about the course itself and his reply was that he agreed with every one of my comments and he itemised them.

author: cjo20
author_rank: Contributor
timestamp: July 27, 2014, 07:52:39 pm
content: Quote from: Simon on July 27, 2014, 07:31:22 pmNope. Not over-thought. It's a typo (bad indent). They ask you to build some circuits. They then ask for a video of building / modifying circuits. It isn't a huge leap to work out that what they want is you to build the circuits they asked you to (and provided components / component values for) and record it.Quote from: Simon on July 27, 2014, 07:31:22 pmI think you just answered your own question. You'll find that with a "low level" of study there will be lots of abstractions and simplifications. They want to know (roughly) what would happen with that circuit, what it would do with input / output voltage / current. It only needs to approximate an amplifier in this case. I'd hate to see what you would make of a GCSE physics course; Complaints because they don't cover wave-particle duality? At GCSE in that case, "light travels in straight lines" is sufficient to get the basic point across. Being a very low level of study.

author: IanB
author_rank: Super Contributor
timestamp: July 27, 2014, 07:55:25 pm
content: Quote from: Simon on July 27, 2014, 07:41:32 pmYou are supposed to provide a short video for each and all of the circuits you are asked to build. The video should show you building the circuit and testing the circuit, with you in the video. This is to provide evidence that you have done the work, and that it is your own work.Isn't this somewhat elementary?

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 07:55:49 pm
content: Well if it is a N channel D mode (depletion mode) MOSFET as per the symbol then maybe you could buy one and play with it..It will typically self bias at 0V Vgs but usually it will be biased quite hard with only a limited amount of +ve swing available for linear operation. But it depends on the device itself I guess.However, it really is a poor choice of MOSFET in my opinion. Figure 1c is the kind of question I would expect a cheeky tutor to throw in at the end of a lecture because it will trap (quite) a few students. But I would expect the tutor to have previously shown me the more common types of MOSFET along with practical circuits and some design theory.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 07:57:08 pm
content: @cjo20 So you're saying that they present to circuits and then after presenting the second asked me to build the first. Excuse me but this is really confusing.I am afraid that all of the amplifier explanations was so trivial that they served no practical purpose. In fact from the whole course you cannot glean enough information to really build anything in practice.

author: cjo20
author_rank: Contributor
timestamp: July 27, 2014, 08:01:08 pm
content: Quote from: Simon on July 27, 2014, 07:57:08 pmIt is generally a good idea to read through assignments thoroughly before you start. At that point it becomes obvious (to me at least).You should be less worried about asking questions that aren't specifically covered in the course text. As you progress further through the education system you are expected to do more and more of your own reading outside what is presented in the course. At degree level it is very common to be asked questions that aren't explicitly referenced in what the lecturer talks about.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 08:02:29 pm
content: Quote from: G0HZU on July 27, 2014, 07:55:49 pmNow you are going way over the expectations of the course. The course never presented enough information to ever buy a physical part. As I said in the video I personally chose a 2N7000 because I felt like it and because there was no information given at all to enable anyone studying from scratch to choose any type of transistor.Remember my point is not that I can't complete the assignment or correct the diagrams so that they work it is that other students who genuinely bought the course to learn from scratch have been totally failed by the course and would have to in fact do a lot of research of their own to find the information they need.No explanation as to how to calculate any values of components was given no example values were given nothing. The are principles of how a basic amplifier works were given and that was it. I still cannot design from scratch a transistor amplifier because this is not something I have ever studied myself and there was not enough information presented in the course.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 08:05:23 pm
content: Quote from: cjo20 on July 27, 2014, 08:01:08 pmWell it remember this is only a BTEC level III and given the total cock up that the course material was officially there was more than enough lateral studying to be done before worrying about further study. To be honest I can't see why multiple questions were asked under one main question heading the whole layout and concept is ridiculous. Remember this is of course the somebody who has never done Electronics before.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 08:08:08 pm
content: And again remember that this course is aimed at foreign students as well who's english is not going to be perfect and who have not gone through the british education system

author: IanB
author_rank: Super Contributor
timestamp: July 27, 2014, 08:09:55 pm
content: Let me provide a model answer for you concerning the FET amplifier question:An FET has a varying resistance according to the voltage that appears on its gate.In the circuit shown Rg establishes a stable reference voltage for the gate so that it isn't floating freely. When a varying voltage Vi appears on the input, the AC portion of this voltage is coupled through to the gate by capacitor C1. This varying gate voltage causes the resistance of the transistor to vary in sympathy and so a varying current flows through Rd and through the transistor. The transistor forms a potential divider with Rd, and the varying current causes a varying voltage to appear at capacitor C2. This capacitor couples the AC portion of this voltage through to the output terminal at Vo.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 08:12:01 pm
content: Yes that is pretty much what I would of said but I would not have been as succinct. When the question of the video was raised on the ICS learn forum and the course administrator basically said the video was not necessary she was in effect trying to drop the inconvenient bit. When we challenged her she never clarified as to which circuit the video was supposed to be of. So as for comprehension of the assignment I rest my case.

author: rexxar
author_rank: Frequent Contributor
timestamp: July 27, 2014, 08:16:12 pm
content: It doesn't tell you to build that circuit, only to explain it. However, there is the instruction to record a video of yourself building it, but that bit of text is pasted at the end of every section, it's not hard to imagine that it got put there by mistake. Considering that you weren't supplied with a FET, nor given any part numbers or values, it seems clear that you're not supposed to build that circuit.I've only skimmed over the assignment, but it seems to be fairly reasonably done. Certainly not the outright scam you seem to think it is.I get that it's easy to see every little problem as a huge fatal flaw when you're pissed, but really every time you've talked about this, you seem to get really defensive when anyone points out that it's not actually that huge a deal. Surely you realize how preposterous it sounds when you say that the whole course is completely broken and unpassable? If it weren't possible to even pass this course, surely someone else would have noticed.

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 08:17:52 pm
content: Here's the transfer characteristic of a small N channel depletion mode MOSFET.You can see it does self bias at 0V Vgs so figure 1c will work with small signals but I doubt you would get much voltage gain from it. Maybe it could be used as a (fairly crude) Hi Z to low Z buffer for small signals?It's not anything like as common as the N channel enhancement mode MOSFET that most people know and understand (and use in industry in vast qty)

author: IanB
author_rank: Super Contributor
timestamp: July 27, 2014, 08:23:44 pm
content: Surely the key thing is that in the course you are not supposed to get caught up in details of N channel or P channel, depletion mode or enhancement mode? Those are advanced concepts for the future. At this level I think you are only expected to recognize that other kinds of transistor exist, such as the FET, and these other transistors can be used as an amplifier in much the same way that a BJT can be used. Details of their design and operating characteristics can come later.

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 08:30:39 pm
content: Quote from: IanB on July 27, 2014, 08:23:44 pmI completely agree and that's why I see question 1c as a poorly worded question that will trap and confuse. Especially those hobbyists who use the commonly available enhancement mode devices. The circuit symbol for each type is very similar and this will trap a lot of people. I doubt many will ever buy an N channel depletion mode mosfet for use in general hobby projects. Radio hams commonly used them in preamps many years ago though.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 09:09:34 pm
content: The depletion mode mosfet was never mentioned, like i said only MOSFET and JFET and while biasing of the BJT amplifier was roughly explained this was not done for the FET variants so can lead to confusion, like i keep saying you are all thinking way over the level of this course. Personally I think the author may infact be knowledgeable but totally incapable of writing things in a simple enough way to get simple concepts across, instead he makes an utter pigs ear of explaining some things either alluding to a more advanced concept when not necessary or simplifying to a degree that makes the explanation pointless. The whole explanation of the FET and it's amplifiers lasts exactly 3 pages, that's it.At the end of the day you would hope that rather than gloss over everything less topics would be covered to a level where the information is actually useful for something. None of the information in the course is sufficient to design anything from scratch. Even the BJT explanation lacked an explicit mention of gain never mind a proper explanation. I think the word gain featured once.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 09:13:50 pm
content: The other problem is that when in doubt a tutor was totally unavailable, it took 6 weeks to get hold of someone and patchy contact from then on. Totally not as advertised.

author: Simon
author_rank: Unknown
timestamp: July 27, 2014, 09:35:02 pm
content: Quote from: G0HZU on July 27, 2014, 08:17:52 pmcheck my video toward the end, it shows you exactly what you get. the transfer characteristic as you show is certainly not linear, I think the basic concept of an amplifier as you would want to explain it in a simple BTEC L3 course is that the in/out relationship is linear. My video shows that you cannot consider the circuit presented a linear amplifier at all although the bit above 2V in the signal could be considered sort of linear, it's hard to tell when the rest of the signal is not being amplified because the circuit lacks biasing.Of course let us not forget that the course teaches that I can use a crappy non RMS multimeter to measure inputs and outputs....................

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 09:46:28 pm
content: QuoteFor your version of the circuit, yes. Because you used an enhancement mode device that is pinched off at 0V Vgs. But of course, the circuit in figure 1c (as drawn in the assignment) 'will' give linear operation for small signals because it uses a depletion mode device that self biases at 0V Vgs. So at 0V bias at the gate it will operate with an idle drain current of somewhere around 10mA to maybe 100mA depending on the device that is chosen.

author: Precipice
author_rank: Frequent Contributor
timestamp: July 27, 2014, 09:54:10 pm
content: Quote from: Simon on July 27, 2014, 09:35:02 pmIf the output isn't distorted, then the gain will show as the same on both a crappy non-RMS meter as on a spiffy RMS meter.If the wave is distorted, then no multimeter is going to show you much of interest (except maybe that the DC bias is wrong enough to be the cause of the distortion).Relying on the 'RMS-ness' of a meter, and telling yourself it says very much about an amplifier, would be a bad choice. I'd suggest that a crappy old meter is fine for this sort of poking around, and that an oscilloscope is the next step up, not a better meter.

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 10:33:45 pm
content: In my opinion some of your course material appears to be based on older technology in days when single gate N channel depletion mode MOSFETs were quite common.Try and buy one today and it will probably have the wrong transfer characteristic because it will probably give a very high idle current at 0V Vgs.If you want to get hold of a suitable N channel depletion mode MOSFET 'today' you might be best to get hold of an old dual gate mosfet and tie the gates together to replicate the circuit in figure 1c. The chances of finding an old school single gate device are quite slim and they could be quite expensive.I've got some dual gate devices here that might work OK with the gates tied together. Ideally you want to find a device that has about 2mA to 5mA drain current with 0V Vgs applied.

author: G0HZU
author_rank: Super Contributor
timestamp: July 27, 2014, 11:36:48 pm
content: I'm a bit bored so I built this circuit quickly.It uses an old school BF981 dual gate N channel depletion mode MOSFET transistor which is probably older than most forum users...By tying the two gates together it effectively becomes the circuit in figure 1c in the assignment. I used a 1k resistor in the drain and something 'big' in the gate (220k ohm?)The supply is 12V and it runs at about 6mA drain current. See below for the crudely built circuit and the waveforms on my scope. It gives a reasonable amount of voltage gain and is fairly linear. Basically, this circuit in figure 1c would have been an exam question in the 1970s or maybe the 1980s.I'd probably be asking the tutor where I was supposed to buy a suitable device in 2014 because I doubt there will be much choice especially if you want a device that biases with just a few mA at 0V Vgs.

author: zapta
author_rank: Super Contributor
timestamp: July 28, 2014, 04:33:55 am
content: Quote from: Simon on July 27, 2014, 05:38:14 pmSimon, I am sorry to hear that you failed the BTEC L3 program.This calls for an honest introspection on how come an intelligent person such as yourself failed and will not get the diploma while others students will. Probably this is not the first time this patterns occurs but you can try making it the last.BTW, the long justifications are meaningless, if you need to explain you failed. Period.

author: ejeffrey
author_rank: Super Contributor
timestamp: July 28, 2014, 04:44:49 am
content: Quote from: zapta on July 28, 2014, 04:33:55 amThat kind of rudeness is just uncalled for, and a mark of poor character.

author: zapta
author_rank: Super Contributor
timestamp: July 28, 2014, 05:06:10 am
content: Quote from: ejeffrey on July 28, 2014, 04:44:49 amNo, this is a sincere reality check. The long explanation is a distraction. Lesser students will get the diploma but he will not.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 05:59:04 am
content: Quote from: G0HZU on July 27, 2014, 09:46:28 pmagain you assuming the course material taught all of what you are talking about. If the course does not teach the student cannot use untaught knowledge to pass an assignment.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 06:03:08 am
content: Quote from: Precipice on July 27, 2014, 09:54:10 pmWell I don't know the finer points of multimeters, it just strikes me as a bad idea and does not allow for circuit diagnosis like a scope does. Fact is without my scope I could not have demonstrated the problems and my circuit would have had a lower output than input and had i been a student who had studied from scratch I'd have been non the wiser. We keep assuming here that your average student knows all that you people know when infact the course material teaches next to nothing and then the assignment needs the sort of knowledge that you gain from higher qualifications just to fix it.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 06:06:00 am
content: Quote from: G0HZU on July 27, 2014, 11:36:48 pmyou are still assuming the course was going to teach me all you know, like i said, the sum total on mosfets and mosfet amplifiers was 3 A4 pages - with big diagrams.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 06:11:13 am
content: Quote from: zapta on July 28, 2014, 04:33:55 amyou obviously got very distracted. I did not fail, I refused to continue with the farce. Remember, you have not seen the actual course material yet, it is an insult to anyones intelligence. It would have been much more productive if they had just sold my employer the assignments and a list of topics I'd need to study in order to do the assignment. The actual course material is poppy cock! every topic ended with a section telling the student to go online to read the same thing again but written in a competent fashion even if it is joe bloggs hobby blog. They also supplied a text book just to make sure they had it covered.Fact is the guy that will fail is that poor sod that is studying while working at sea with no internet access or to alternative components in the kit, tell him to solder wires onto a potentiometer so that it can be used. Whoever chose the parts for the kits was totally incompetent and had no understanding of what they were ordering, infact the pot turned out to be a double one.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 06:12:53 am
content: Quote from: zapta on July 28, 2014, 05:06:10 amIf you want a long explanation would you like to see the reels and reels of emails I have ? I raised concerns about the accuracy of the material soon after receiving it.

author: bwat
author_rank: Frequent Contributor
timestamp: July 28, 2014, 06:52:01 am
content: Quote from: zapta on July 28, 2014, 05:06:10 amI have to agree with zapta.Quote from: zapta on July 28, 2014, 05:06:10 amNail hit firmly on the head. Put your engineering hat on and see it as negative feedback.Quote from: IanB on July 27, 2014, 07:11:51 pmAgain, someone else who is spot on. I see a lot of people on these boards who seem to eitheri) have a problem with reading comprehension, orii) they "read" what they expect to be written and not that which actually was written.Either way it's a serious limitation.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 06:56:19 am
content: except this is not a diploma, it's a playschool certificate. It's just a L3, L5 gets you a decent certificate, L8 is the only one called a diploma - HND - Higher National Diploma

author: Psi
author_rank: Super Contributor
timestamp: July 28, 2014, 07:14:09 am
content: There is definitely a link between having pre-existing electronics knowledge and finding electronics qualifications difficult, i've seen this first hand.It's quite often necessary when teaching to flat out lie about how something works, or at least bend the truth, in order to make the concept simple and easier to understand. Once the concept is understood you can build on it.Only much later does the lie become obvious, but you need all the "semi-true" concepts in your head in order to grasp the big picture.And that approach causes problems with people who already know the big picture when starting the course.

author: AndyC_772
author_rank: Super Contributor
timestamp: July 28, 2014, 07:29:51 am
content: I agree. My A-level electronics course was pretty bad; the course material was outdated and full of mistakes, and the teacher I had was clearly learning the same material from the same course books at the same time, albeit a bit more slowly.But: passing that course was a tick in a box that got me into university, which in turn was another tick in another box that got me my first job, and subsequently, a career in the industry. I wouldn't be where I am today if I hadn't passed that course at school over 20 years ago.That's why I think it's a big mistake to drop out of a course before completion, regardless of how bad you think it is. Pass the exam, get the tick in the box, THEN complain about it if you still feel it's necessary.Prospective employers will not, I absolutely guarantee, care why you failed to pass the course. "If at first you don't succeed, destroy all evidence that you tried" may be good advice.

author: bwat
author_rank: Frequent Contributor
timestamp: July 28, 2014, 08:12:57 am
content: Quote from: AndyC_772 on July 28, 2014, 07:29:51 amDepends. If he goes on to get a higher qualification or can demonstrate competence with either a good portfolio or an ability to confidently answer technical questions, then not many would hold it against him. He can easily argue that failure to finish is a case of getting out of a bad situation, and not because of an inability to learn.

author: AndyC_772
author_rank: Super Contributor
timestamp: July 28, 2014, 08:40:41 am
content: If he gets a higher qualification, then there's no benefit at all to be had by mentioning an earlier failure to achieve a lesser one.I'm not at all convinced that "obvious technical competence + failure to achieve a qualification" gives a better impression than obvious technical competence alone.A failure is always going to have an element of doubt associated with it. Did he just have a bad day? Personal issues at the time? Maybe. But there's always the possibility that, when it comes down to it, he's just not that good at solving problems and getting them right all the way to completion, or perhaps he gives up too easily in the face of difficulty. Why sow that seed of doubt in an interviewer's mind if there's no need to?

author: GK
author_rank: Super Contributor
timestamp: July 28, 2014, 08:58:32 am
content: http://www.urbandictionary.com/define.php?term=Whinging%20Pom

author: bwat
author_rank: Frequent Contributor
timestamp: July 28, 2014, 09:12:16 am
content: Quote from: AndyC_772 on July 28, 2014, 08:40:41 amI'm a uni drop out and it's never kept me back. Of course I'm not talking about an area which requires chartered status (law, architecture, medicine, engineering, etc.) but I can demonstrate I've got the skills and that seems to count for a lot. When I've been the interviewer, I've never looked at qualifications though a lack of qualifications might have prevented the interview from happening. Also, I've recommended plenty of others I've worked with to employers and not known a thing about their educational backgrounds.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 12:08:08 pm
content: Failure ? who ever said I failed ? having corrected the many mistakes in the main course material I refused to correct the assignment as well. My aim is to ultimately go for a HNC and then a HND, I don't need this shitty L3 BTEC to get on a HNC because anyone with relevant experience is acceptable to the HNC course. This L3 is for people who just want to impress, it has no real value at all in the real world. The knowledge this L3 gives you will not enable anyone to design jack shit, it's not even hobby level, most beginners on this board could exceed the knowledge (or lack of) in the course.

author: Codemonkey
author_rank: Regular Contributor
timestamp: July 28, 2014, 12:32:31 pm
content: Quote from: Simon on July 28, 2014, 12:08:08 pmHow do you know ? You failed to complete the course.I suspect you're going to struggle even more with the HNC not having the base level of knowledge that the lower level course provides. Will you declare that to be a mickey mouse course as well and throw your toys out the pram ? Unless you sort out the holier than thou/know it all attitude , you're already setting yourself up for another fail. I hope to be proven wrong however.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 12:44:38 pm
content: I read one whole module of the L3, it was certainly lower than the level of knowledge I have, due to the errors, and I mean technical errors I feared reading any more of it. It was not just me complaining about the course but other students too especially when I explained the errors they started to understand things and how bad it was. A total lack of the promised tutor support did not help either.A HNC would certainly have something to teach me.Lots of people seem to be making lots of assumptions, it's like the pot calling the kettle black ?

author: bwat
author_rank: Frequent Contributor
timestamp: July 28, 2014, 12:52:05 pm
content: Quote from: Codemonkey on July 28, 2014, 12:32:31 pmBut not all failures are created equally. I once dropped an astronomy course because I couldn't make out the colours very well on the star chart and so couldn't really tell how the stars were moving. Everybody else was steaming through the tasks at the tutorial but I'm like "Eh?" Was that a failure? It was a failure to complete the course but I don't class it as anything other than a bad fit between my eyes and the coursework.I also failed a maths exam at uni with 0% then got over 90% on the resit after the summer. Was that a fail or a pass or both?I think it's up to Simon to be honest with himself and ask himself if he's failed or not. What we think is neither here nor there.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 12:58:57 pm
content: I refused to continue the course, I explained to my boss who is well aware of my abilities that it was not of a very high level, he thought it was quite a decent level but he's not been involved in education of late. I even said before I took it that I wondered if it would be more than "heres a voltage regulator" he said he would expect it to be higher than that but it turned out that vague familiarity with components to a dodgy standard is the best you get. I have an email from my tutor in which he agrees with every comment i made about the technical accuracy of the course. I'd not be surprised if both tutors who seemed to be working part time from home and possibly retired gave up working with the company as they seemed more concerned about the problems I was raising than ICS and I'm sure they don't want to spoon feed the entire class who started asking me for help.

author: Yago
author_rank: Frequent Contributor
timestamp: July 28, 2014, 01:25:00 pm
content: Some shenanigans went on in the HND course I did way back when.Basically similar, in that a test was done on material that had not been covered in the course (so far).Unfortunately for the college, I alone passed (with a distinction too).They took me to one side and asked if I would let the whole thing go quiet and the results be buried.Meh, I agreed and got on with things.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 01:35:11 pm
content: I don't mind lateral study on a HNC/HND so much as the qualification is worth while, but I'm not going to be the guy composing poetry in a playschool trying to learn the alphabet. I have a friend that told me that his HND was not great. The one I'm planning is a HNC with Teeside university by distance learning, again by distance learning, I just need to sort out my maths first as I don't have the qualification in maths they ask for so may need to do a maths course or take a little paper if they think I can hack it. I phoned them and asked and they said to just fill in an application form and explain my situation and they would work something out for me. Once the HNC is done I can look at a HND. I do struggle to some extent with study and I'm well aware of that and I'm certainly not stupid, that is why I didn't mind doing the L3 at first but not on these terms.I got this about a minute ago from a fellow student on the course (well not fellow anymore as I left):Hello Simon ,Sorry to bother you. I was wondering if you managed to get your refund for the course? if so can you please let me know who to email to do the same as i have just about had enough of it now.Many thanks

author: Berni
author_rank: Super Contributor
timestamp: July 28, 2014, 01:57:10 pm
content: Sorry to hear about your trouble with it, I agree that that assignment should have explicitly said it needs an unobtainium MOSFET manufactured by nude virgins to work. Just putting a typical MOSFET in the schematic assumes that any N channel device works. Or even better give it some biasing to make it work with any typical MOSFET out there, while they are at it also add a resistor to ground to stabilize the operating point and make it much more likely to work rather than shooting for the right bias in the dark.But it is fairly typical for school to teach useless and/or outdated things, occasionally there is even a mistake. So far I have not seen a school that actually spits out capable electronics engineers out the end of there programs. Some of the theory stuff is occasionally useful later, but in order to learn to design circuits from scratch, decode how stuff works from schematics etc you have to do hobby electronics on your own. There is a lot to learn from the magic smoke you let out from a component on a breadboard during some random messing about over a weekend.As for school just do what they want so you get the piece of paper in the end. Yes that paper only proves you ware persistent enough to get trough the classes, but some people think that the paper actually proves you know something about electronics. Show up at your job interview with your latest weekend project instead, but have the piece of paper ready if they think its actually worth something.

author: IanB
author_rank: Super Contributor
timestamp: July 28, 2014, 02:00:53 pm
content: I just quickly reviewed the course specification and objectives for the BTEC L3 in electrical/electronic engineering.This is a vocational course aimed at high school age students of about 18 (sixth form in the UK, grade 12 in the USA, for example). It is similar in size to two A levels and might be taken by students who are not on the more traditional academic track. It's stated purpose is to introduce some introductory and conceptual knowledge of electronics sufficient for the student to progress to higher level study at university, or to enter the workplace as a junior employee where they will receive further training.As set out the course may therefore be expected to convey conceptual knowledge in a broad context, and will make many simplifications along the way. One does not expect students at this level to perform detailed design calculations or advanced analysis.One of the stated goals is to "give learners the opportunity to develop a range of skills and techniques, personal skills and attributes essential for successful performance in working life."I think this is important. Getting through the course demonstrates an ability to get through a course of study, follow instructions, do the work, comprehend what is being required and not get tied up in what is not required.I have a feeling you have rejected the course because it is "beneath you". But I think you have rejected an opportunity to get familiar with the education system and get into the mode of how to study and pass tests. This may be to your disadvantage when you move to more advanced courses of study.

author: Simon
author_rank: Unknown
timestamp: July 28, 2014, 02:21:43 pm
content: There is vocational and there is factually incorrect. For such a simple course the quantity of errors is unreal. Obviously my boss is certainly not ware of how basic vocational is. The information taught was so basic that it was not worth learning, you might as well learn it as though it was nothing on a higher level qualification.I do infact care more for what i have learnt so far on my own and by doing my own projects. if I was going to an interview it would be clear that I'm not some bloke with a bit of paper and nothing else. The whole reason I am being asked to take qualifications is because my employer is finding it cheaper and faster and more essential to have an inhouse person than rely solely on a subcontractor who's mistakes I started correcting (seems he's never heard of bypass capacitors and screwed up plenty of designs). We once got in a fix where my boss had failed to understand some of the components he was using properly and our expensive long lead time control box from our subcontractor was therefor not going to work. I let them argue about it and try to work out a solution (the suby quite rightly needed money and time to work on it again that we did not have or want to pay). After a week I chipped in and offered to create an additional circuit to "fix" matters. My boss agreed as we were about to go overdue on delivery. I made the circuit and it all worked fine. I was then asked to create a more production intent version on a PCb rather than a breadboard and things started to roll from there. during this time I continued to study in my own time and during down time at work on how to program AVR's in C rather than use the arduino and I am now creating circuits for my employer on PCB's when I am asked. At this point my boss asked me if i was willing to take some qualifications and that he was aware of how much it would benefit me as he knows that I am very keen.This from what I had 2 years ago when I was told on offering that I'd never do any electronics for them as they had a subcontractor to handle it and i would only do mechanical design. I am also the reference point for anyone in the company who needs some electrical knowledge even if it's how to get 5V from 24 to get a brush-less motor to go at the right speed (zener and resistor).

author: Berni
author_rank: Super Contributor
timestamp: July 28, 2014, 02:31:38 pm
content: Hmm 18 that sounds quite late. I had to calculate things involving phase shift and such on circuits with capacitors and inductors along with parametrizing values in discrete amplifiers and such back when I was about 16 or 17.I had to deal with teachers that had no clue of the subject and occasionally said something that was just plain wrong, but then again there was a few great ones that could actually teach the subject in an intesting way and are in general great people to talk to. They are often the ones that are truly passionate about electronics and teach it for the love of the field not just for the paycheck at the end of the month.For the clueless in it for the paycheck baboons you just have to find the path of least resistance trough there subject so you get over with it using the minimal amount of work.(bonus points if you can straight out cheet trough the tests)

author: IanB
author_rank: Super Contributor
timestamp: July 28, 2014, 03:04:41 pm
content: Quote from: Simon on July 28, 2014, 02:21:43 pmI don't recall you giving any examples here of something that was factually incorrect. What I recall were things that were either simplified or things that were presented in a way different from your understanding.For you this course should have been the warm up exercise, the gentle jog round the park before the race begins.Your reaction has not come across well at all, which is why you are not getting a lot of sympathy on this board.Example of good reaction: "Oh, I see they have simplified this a lot. I get why they did that. Let me go with the flow."Example of bad reaction: "Arghh! This is all wrong! It's not like that at all! My pedant meter has gone off the scale!"Part of it would be getting back into the formal education system. When was your last contact with formal education? Maybe GCSEs?It takes a certain mindset to get through the system and be a successful student. You need to learn not always the technical material, but sometimes just learn how to study. To adopt a sense of humility, to buckle down to it, to overcome the hurdles, and to get things done as asked. (Just the same as the workplace, actually.)I'm afraid that if you think an HNC or HND will be different, you may be in for a surprise.

author: IanB
author_rank: Super Contributor
timestamp: July 28, 2014, 03:08:18 pm
content: Quote from: Berni on July 28, 2014, 02:31:38 pmYes, but this is a vocational course, not an academic course. It is for students who would have left school at 16 because they did not shine academically (for example did not do well at mathematics). It is giving such students a different option for further study.

author: Berni
author_rank: Super Contributor
timestamp: July 28, 2014, 03:22:18 pm
content: Ah, we don't have such a option here. In that case I would have expected more hand holding sort of approach like give all resistor values and pinouts and such right next to the schematic.

author: cjo20
author_rank: Contributor
timestamp: July 28, 2014, 03:44:18 pm
content: The BTEC Level 3 certificate (which I believe is 'extended' in the case of electronic engineering) gives 60 UCAS points when you gain a distinction (20 points for a pass).60 UCAS points is equivalent to a D at A level, or an A at AS level. 20 points is an E at AS level.AS levels are typically started at 16 and finished at 17 in the normal education system; I was still (just about) 16 when I sat my AS exams, 17 by the time the results came through. This is not meant to be a technically detailed course. And the distinction between "wrong" and "simplified" is extremely important.

author: IanB
author_rank: Super Contributor
timestamp: July 28, 2014, 03:59:02 pm
content: Quote from: Berni on July 28, 2014, 03:22:18 pmPerhaps like this?

author: G0HZU
author_rank: Super Contributor
timestamp: July 28, 2014, 04:41:26 pm
content: Quote from: Simon on July 28, 2014, 06:06:00 amI'm really just addressing your (incorrect) claim that the FET circuit in Task 1(3)c is somehow 'not' a proper amplifier circuit. Your claim that the amplifier circuit in fig 5.5 is drawn incorrectly seems to be the basis of your rather angry video on Youtube.In reality I think you need to admit your assessment of the circuit was incorrect and that it is indeed a valid amplifier circuit because it shows an old school N channel D MOSFET. You got confusing results in your youtube video because you used an E MOSFET instead. This device has a different circuit symbol to the D MOSFET device shown in the assignment.However, I can sympathise with your error here because I think a lot of modern students will fall into the same trap as yourself. But your course tutor might have been a bit offended by your video. Maybe you should take it down or produce a new version?I suspect that the course material is based on old material and the reason that you didn't get supplied with the (effectively obsolete) FET in question is because they are so hard to find in 2014Back when I was a student in the 1980s these devices were sometimes (casually) called single gate IGFETs but even then they were going obsolete in favour of the dual gate flavour of the device. So strapping gate 1 and gate 2 together was a common workaround even in those days if you wanted a small single gate D MOS FET which had a drain current of a few mA at 0V Vgs bias.So maybe the fact these parts are hard to source in 2014 is the reason why they ask you to describe the operation of the circuit rather than directly instruct you to build it. If this course material dates back a few decades then maybe there was a time when they supplied you with the FET?But the bottom line is that this old school D MOSFET is the simplest to understand because it can operate with 0V bias and still produce a reasonably linear signal.Therefore, the sample answer given by IanB back in post #24 would probably have achieved high/full marks. Some people write books on these devices but I think IanB tried to give the 'expected' answer for high/full marks in your course

author: Berni
author_rank: Super Contributor
timestamp: July 28, 2014, 04:44:17 pm
content: Yes like that, but I was referring to the FET amplifier one. The BJT one I think is an excellent example of showing that a BJT can be used to switch a large current using a small one.

author: IanB
author_rank: Super Contributor
timestamp: July 28, 2014, 04:51:25 pm
content: Quote from: Berni on July 28, 2014, 04:44:17 pmRemember, the student was not asked to build the FET amplifier, the student was just to give a qualitative explanation of its operation.

author: zapta
author_rank: Super Contributor
timestamp: July 28, 2014, 05:48:11 pm
content: Simon you come as an intelligent person that can do well in life. Here are humble advices from somebody that went through the process a few times.If you want to get diploma X, do whatever you need to achieve it and don't let your ego distracting you .If on the other hand diploma X is worthless, don't even bother to register for it.Arguing about home assignments will get you nowhere. It's like full throttle in neutral.Keep your eyes on the ball and you will do well.

author: G0HZU
author_rank: Super Contributor
timestamp: July 28, 2014, 09:01:55 pm
content: I found a SPICE model for a modern dual gate N channel D mode MOSFET and tied the gates together and produced the circuit below:You can see it's effectively the same circuit as the one in the assignment with 0V bias at the gate. You can also see that this works quite well as a small signal amplifier because the output waveform is still a nice sine wave. It works in a similar fashion to my BF981 version I put together on my workbenchIt works because the BF998 is an N channel depletion mode device and will have the required idle drain current of just under 2mA when both gates are at 0V so it will operate in a reasonably linear manner even for very tiny signals of a few mV.The reason I posted up this simulation is because the BF998 is a modern part that you can buy from Farnell or ebay etc etc.However, it is a tiny SMD device so not suitable for breadboards! But you would at least be able to demonstrate the operation of the old school single gate N ch D MOSFET circuit in the assignment if you wanted to.Note: The 4.7k resistor R2 in the drain has been chosen as a fairly optimal value for the SPICE model. In reality, you may find that a 'real' BF998 will have a higher idle current than the SPICE model so you would have to reduce the value of R2 accordingly or else the device will saturate like a switch if the real BF998 has an idle current of 5mA (at Vgs =0V) for example.Obviously, that's why my BF981 bench circuit in my earlier post has a 1k resistor in the drain. It has an idle current of about 6mA so I achieve a voltage drop of about 6V across it to place the drain voltage at half the supply rail voltage

author: G0HZU
author_rank: Super Contributor
timestamp: July 28, 2014, 09:40:01 pm
content: Hope nobody minds me posting all this stuff up but here is the transfer characteristic of the BF998 from its datasheet.You can see that if you tie both gates together at 0V you can expect an idle current of just over 2mA at Vgs = 0V?You can also see that the black transfer curve that crosses this point is fairly linear for small changes in gate voltage. But you also have to take into account that you will be changing BOTH gates in sympathy so the transfer will be higher than just the basic curve slope shown.

author: G0HZU
author_rank: Super Contributor
timestamp: July 28, 2014, 09:52:56 pm
content: You can also see why this sexy dual gate device made the single gate N channel depletion mode 'IGFET' devices obsolete fairly quickly in the late 1970s and early 1980s..By using it in dual gate mode you can use it as a variable gain, cascode amplifier by applying the signal to gate 1 and then feeding a decoupled dc voltage to gate 2.If you then change the gate 2 voltage higher you can see how much steeper the upper transfer curves are on the graph. The top curve is for gate 2 at 4V dc. So you get more gain at higher gate 2 voltages. So you can set the gain according to the dc voltage level at gate 2.You can also use it as a mixer if you ac couple an LO signal to gate 2 instead of the variable dc voltage. This is because the ac coupled LO signal 'varies the gain' at the rate of the LO frequency and this gives the non linear mixing effect. You could do the same thing with a +/- dcV fed potentiometer at gate 2 if you could wiggle it up and down as fast as the LO frequency!

author: Precipice
author_rank: Frequent Contributor
timestamp: July 28, 2014, 10:17:09 pm
content: Yeah, I just bought a reel of Siemens BF 1012* dual gate FETs to have a play with, a couple of weeks back. Not depletion mode, though, so I think if we want to chatter about our adventures with tetrodes, we ought to fire up a new thread for it and leave Simon's alone?I was going to knock out a little PCB with connectors and support gubbins, since SOT-143 is a bit of a pain to breadboard, and if this device promises 1GHz, I'd like to at least get near.* Datasheet starts withSilicon N-Channel MOSFET Tetrode•For low noise, high gain controlledinput stages up to 1GHz•Operating voltage 12V•Integrated stabilized bias network

author: Wilksey
author_rank: Super Contributor
timestamp: July 28, 2014, 10:19:47 pm
content: All distance learning facilities in the UK are useless, may I ask why you want to complete a BTEC? I have a HND in electronics and computer engineering, and never wanted to go to degree level, I got a few books, one of which was the Art Of Electronics, and now 10+ years later, I am glad I didn't go to Uni to do the 1 year top up to a degree level. People I work with have PHD's in various subjects, usually robotics and I find myself teaching them things about how to calculate Op Amps and the like. I think with a subject like electronics that experience speaks volumes over a educational qualification.P.s. I think I bought some LED's from you off of E-bay, I didn't realise you were a moderator here!

author: eneuro
author_rank: Super Contributor
timestamp: July 29, 2014, 07:25:09 am
content: Quote from: Simon on July 27, 2014, 05:38:14 pmI like those online MIT courses seriesMIT OpenCourseWareand thenit and hopefully physics works without any certifications

author: bwat
author_rank: Frequent Contributor
timestamp: July 29, 2014, 07:48:32 am
content: Quote from: Wilksey on July 28, 2014, 10:19:47 pmUniversity is about being introduced to ideas and people you wouldn't otherwise. The internet has introduced the ideas part to people who don't go off to uni so maybe that's not so important these days, but the people part is never going to be replaced even by videos. I once took a course where there were only five or six students and the lecturer was a genuine pioneer in the subject. With so few students he could tailor his lectures to us individually and we could ask stupid questions without disturbing the whole group. One of the things you realise when you come into contact with proper experts is that they're human too. It makes it all much more achievable knowing that.Quote from: Wilksey on July 28, 2014, 10:19:47 pmIt's probably not an effective use of their time to learn to do the calculations and your time is probably much cheaper. They have their specialisations and you have yours.

author: Wilksey
author_rank: Super Contributor
timestamp: July 29, 2014, 10:22:54 am
content: University teaches you how to research, and the only time a question is stupid is if you already know the answer but can't think, then it becomes obvious when someone tell you the answer.Some people benefit, but what you also have to remember is that the lecturers don't know everything, they only know what they have learnt themselves, everything else is just a guess, or found on the internet, and most of the lecturers I have come across don't know anything else but the basics, unless in a specialist area such as robotics, then they might know the best way to drive a multitude of motors.Sometimes as well as realising that the "experts" are human, it also helps to realise that sometimes there is a huge team and resource behind said expert, that also helps a lot!If you work out the basic rate per day for a person mine is a lot higher than the PHD people as I have worked my way up through the years, it's just down to experience rather than specialisations.

author: bwat
author_rank: Frequent Contributor
timestamp: July 29, 2014, 11:29:39 am
content: Quote from: Wilksey on July 29, 2014, 10:22:54 amThis is true of everybody, no? How can we know that which we have not learnt?Quote from: Wilksey on July 29, 2014, 10:22:54 amI think we have experience of quite different lecturers and quite different subjects.Quote from: Wilksey on July 29, 2014, 10:22:54 amThis can be said of most specialists in the modern world.

author: Wilksey
author_rank: Super Contributor
timestamp: July 29, 2014, 12:14:55 pm
content: Yes, but a lot of students know bugger all before going to these lectures, those of us that do / did find themselves not taken any notice of, more of a "how dare you correct me" kind of attitude in my experience.I studied electronics and computer engineering, and that was my experience.What I mean regarding speciality subjects is, if you have a PHD in robotics and get a job doing robotics, great! Most of the time this doesn't happen however, so we have robotic PHD students doing general electronics, tasked for example, with designing a PSU and can't do it, it's not their fault, don't get me wrong, I am not saying they SHOULD know it, or that I have any objection to helping them, I am just saying that University and degrees, PHD's and the like are not the bee all and end all of it.I did further education myself, do I regret it? No, would I recommend it? Yes, if that is what you want to do. Did I learn anything? Yes, did I get a better job because of my qualifications? No.Times may have changed, but when I was looking at the options of further education (Uni) or getting a job, employers were more concerned over experience and "can I do it" rather than "have I learnt about xyz, or can I find out how to do it". Tinkering and hobbying helps of course as you gain valuable experience from actually doing something, and it's no fun unless you blow up a capacitor or two!

author: bwat
author_rank: Frequent Contributor
timestamp: July 29, 2014, 12:37:44 pm
content: I don't think you and I are a million miles apart in our views here. My claim is that university is about exposure to ideas and the people who are genuine experts. I specifically avoided mentioning the qualifications because I don't think it's that important, and like you, I too have worked with people who have the qualifications but not the ability to deliver solutions to everyday problems.

author: AndyC_772
author_rank: Super Contributor
timestamp: July 29, 2014, 12:53:46 pm
content: Quote from: bwat on July 29, 2014, 12:37:44 pmThese are two different requirements which suit two different kinds of problems, though.The example I usually cite is one which also crops up in the perennial 'engineer vs technician' debate also, and it's comparing an automotive technician (ie. a mechanic) with a mechanical engineer.The mechanic is, of course, the person you'd go to if your car's engine breaks and needs to be rebuilt. You need someone with a lot of real-world practical experience in getting engines apart, identifying and replacing failed components, and getting it all put back together according to the specifications in the service manual. It's a highly skilled job by any standard.By contrast, the mechanical engineer might not have a clue what to do when faced with the first seized bolt. But that's not the engineer's job; the engineer's job is to establish the root cause of that reported failure, and to design that weakness out of the next generation of engine - while, at the same time, making it 15% more powerful and 20% more fuel efficient than the previous generation.That's not something you can learn 'hands on' in a workshop; it requires a detailed, theoretical understanding of materials properties, thermodynamics, manufacturing processes, CAD and so on, which come from academic study. These are skills which simply don't apply to a mechanic's job, any more than the ability to undo a rusty fastener with limited access applies to the engineer's job.

author: bwat
author_rank: Frequent Contributor
timestamp: July 29, 2014, 01:07:42 pm
content: Quote from: AndyC_772 on July 29, 2014, 12:53:46 pmI'm talking about people with degrees that can't solve the type of problems that others with similar degrees can. I've met CS graduates that didn't know what Amdahl's law was. My undergraduate studies were as theoretical as they get and even I was taught that.

author: Wilksey
author_rank: Super Contributor
timestamp: July 29, 2014, 03:12:06 pm
content: I may sound old (i'm 31), but I really don't if degree courses are getting easier or if people are just managing to wing them because some of the people (note I said SOME) are really not playing with a full deck!When I was studying, theory was key and hands on was just a bonus, that is part of the reason I didn't want to go on, I wanted to get my hands dirty in the real world, so to speak!Some of the graduates I have (I use the term loosely) "worked" with really should not have passed their exams / tests whatever you will because they lack basic fundamental knowledge which, if left to design or even assemble a SMPS for example could seriously injure themselves, maybe it's just a lack of common sense, but whatever it is, I don't know how they passed.Now, on the other hand I have met some really clever graduates that want to learn more, admit they do not know everything and will take the time to learn and are actually pretty darn good at what they do, some of their ideas, in line with what bwat has said, are superb and I would never have thought of some of them.If you have just left school and want to go on to further education then I would recommend it if that is what you want to do, if you are already in work and you require a qualification for whatever reason for work purposes, or if they are willing to pay for it (hey it's free, why not!) then go for it, if it is just out of boredom or you want to learn something new, I would not personally have thought it worth going to Uni / College etc.In terms of different problems and requirements, that is also correct in some sense, I would not trust a software engineer to program my FPGA, on the other hand, there are some software engineers that could program one better than I could, so it really does depend on the individual.I for one try and have a go at anything if it is safe to do so, if I mess it up then so be it, i'll either try again or give up depending on if I really don't think i can do it.

author: G0HZU
author_rank: Super Contributor
timestamp: July 29, 2014, 05:05:59 pm
content: I did some digging to try and find a datasheet for a suitable old school N channel D MOSFET and found the classic 2N3797 from Motorola. This device probably dates back to the 1970s. I don't have one here to prove it and these old devices now cost a lot of money to buy if you look on ebay. £10each buys you this little slice of history...You can see in the snippet from the datasheet below that this device has the correct transfer characteristic. i.e it has a small drain current of about 3mA flowing when Vgs is 0V. Therefore, if this classic old device were fitted to the circuit given in the assignment then I think the circuit WILL work as a small signal amplifier despite all the criticism from Simon on this thread and also in his video and the other eevblog thread here:https://www.eevblog.com/forum/projects/'subject-matter-expert'-required/.QuoteObviously, if you fit the correct device (i.e the correct N channel depletion mode device as depicted by the circuit symbol in the assignment) then the circuit WILL work as a small signal amplifier.So Simon is clearly wrong to criticise the course material here and also, the BTEC tutor can not be labelled an idiot for releasing this FET circuit on the course.The plain and simple fact is that Simon made the error of using the wrong type of MOSFET and then threw a tantrum on youtube about the quality of the course and insulted the tutor(s). Was that wise?

author: 8086
author_rank: Super Contributor
timestamp: July 29, 2014, 05:08:43 pm
content: Simon, take this from another Simon, no matter how smart you think you are, do as you're asked and make no assumptions on a course like this.Don't criticize the content unless you are absolutely, 100%, totally, completely sure you are correct and they are wrong.You did what many people do, and you let yourself become your own worst enemy.With respect, you screwed this up.

author: fcb
author_rank: Super Contributor
timestamp: July 29, 2014, 05:20:08 pm
content: I tried to watch the first 30 seconds of Simon's video, but it was just to quiet - any chance you can repost the video with the levels sorted.

author: G0HZU
author_rank: Super Contributor
timestamp: July 29, 2014, 05:25:23 pm
content: Quote from: 8086 on July 29, 2014, 05:08:43 pmYup... MOSFETs can easily catch anyone out because there are so many flavours of them and lots of associated symbols.In my day I was taught the way to reverse engineer each MOSFET circuit symbol because the symbol consists of various clues to actually tell you what the device is and (more critically) how the channel behaves electrically. i.e. there is critical behavioural information locked into each symbol. Once you know this you can often tell at a glance if the circuit is valid or not.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 29, 2014, 05:29:00 pm
content: "assuming" the OP claim is valid even though he didnt provide any hard proof, esp lecture content and lecturer/tutor proficiency.... either way anyway, as someone said,mission failedordirective unacomplished. its about putting the ego aside and play with the rest. there are more than skills and knowledges, things like humble, respect, willing to ask and discuss politely or simply shut up no matter how foolish the person you are facing at, esp your tutor where your fate is lying on him. now dont get me wrong i wont encourage but licking either, there are people who want to make money for a living, there are people who want the scroll for a better place, in the end both will get win win situation. if you think its a fraud? then dont do it, you get the scroll. you explained to them but they didnt listen, then leave, you get the scroll. ego aside, you get the scroll, mission accomplished, directive accomplished, otherwise its a failure no matter what mr anakin says.back to the question, i'm nearly went mental to find amp circuit in "task 1 c", with higher level of concentration then i found its actually "task 1 question 3 c", i dont see any problem, the directive is to explain the circuit input and output result in plain verbal tone level, if its not working, then explain why (or simply say i dont know why as most normal kids will say anyway) in plain verbal tone level, if you have better suggestion (to prove your proficiency) then please do so in plain verbal tone level, thats it, whining is not required. that shows your profesionalism and to avoid being seen as a "foolish whiner" no matter how briliant you are (or think you are).and think my last point is.... expecting an "engineer" or "a professor" to know how the "dirt bolt and nut is" or "dave should be able to fix any tv because he is an engineer" is a foolish thought no offense its just plain truth. just because you have not living the life doesnt necessarily put you in an "absolute truth" position. i dont think i want to explain further why, others have tried.