hybridfree/eevblog-posts huggingface dataset:
Fluke 73 innards? - Page 1
Forum section: electronics / general

author: desolatordan
author_rank: Regular Contributor
timestamp: June 29, 2010, 03:01:21 am
content: I opened up my Fluke 73 III and one of the components next to an input fuse looks like it's cracked. The multimeter still functions fine. It looks like it could be a PTC or something of that nature. Unfortunately I can't find a schematic of the 73, only the 77. I'm also having trouble getting the PCB out of the case, something near the input jacks is holding it down but I can't find it for the life of me. Ideas? I'd like to replace the part if possible. I'd take a picture but I don't actually have a camera...

author: EEVblog
author_rank: Unknown
timestamp: June 29, 2010, 04:22:01 am
content: It most probably the spark gap, if it looks like a nice clean gap right down the center of the device. This is normal.Service manual is here:http://www.eserviceinfo.com/index.php?what=search2&searchstring=77Dave.

author: desolatordan
author_rank: Regular Contributor
timestamp: June 29, 2010, 12:41:45 pm
content: It's a clean, but it doesn't go all the way through the device. And it's one of those dipped components, looks like this:https://www.egr.msu.edu/eceshop/Parts_Inventory/images/270%20pf%20ceramic%20capacitor.jpgThat service manual looks to be only for the 77, which has a different layout and parts than the 73. Fluke's website only has the 77 series manual as well.

author: slburris
author_rank: Frequent Contributor
timestamp: June 29, 2010, 01:18:04 pm
content: Does it look like the blue component near the fuse in the attached photo?This is a picture of my 73-III.If so, that's normal.Scott

author: desolatordan
author_rank: Regular Contributor
timestamp: June 29, 2010, 01:52:55 pm
content: Quote from: slburris on June 29, 2010, 01:18:04 pmYes, exactly, only yellow. Thanks, didn't realize spark gaps came in that kind of package.
RAM and ROM Routing Nightmare! - Page 1
Forum section: electronics / general

author: David
author_rank: Frequent Contributor
timestamp: July 01, 2010, 10:20:42 am
content: Hi all,I am having a bit of a problem trying to route two IC's together on a new version of my development board. The problem is illustrated in the attached diagram. Basically I cannot get both the Ram and Rom IC's in the same package so the Rom must be a TSOP-I 48 pin while the Ram is a TSOP-II 44 pin. The two ic's must be in the arrangement shown and the address and data bus locations must be in that position. Now the headache comes because both memory devices use the same buses! I have successfully routed the IC's on the first version of my board (show below) but the Ram IC is upside down and obviously looks quite unprofessional! Any ideas?!In an ideal world the RAM would also be a TSOP-I 48 pin with the same pin-out. Now these devices do (or did...) exist but seem to now be obsolete!Cheers,Dave

author: nessatse
author_rank: Regular Contributor
timestamp: July 01, 2010, 11:33:29 am
content: On the RAM chip you can pin swap the address and data bits as much as you need to facilitate routing, since the bit numbering is somewhat arbitrary from an external point of view. Would that help?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 01, 2010, 01:28:53 pm
content: Quote from: nessatse on July 01, 2010, 11:33:29 amYou can also do the same for ROM if you shuffle the contents before programming!This is the sort of layout job where you need to route the PCB Before comitting pins in the schematic. Some PCB packages allow component pins to be defined as equivalent and it will auto-swap to reduce net length.

author: David
author_rank: Frequent Contributor
timestamp: July 01, 2010, 05:30:33 pm
content: After many hours this is what i've come up with so far...needs some refinement but it should work. I know the track lengths are different and will cause timing differences but as the memory won't be accessed at very high speeds I hope this is ok...Dave
Australian engineering job market  - Page 1
Forum section: electronics / general

author: MAN
author_rank: Newbie
timestamp: June 24, 2010, 08:09:39 pm
content: Hi.Is anybody informed about Australian labour market? Is it difficult to find a job of the engineer with following skills:- PCB development (Accell EDA15, PCAD2006, now studying Altium);- AVR 8-bit microcontrollers based devices development, their programming.Internet has hinted me that AVR microcontrollers aren't very popular :-(Thanks.

author: EEVblog
author_rank: Unknown
timestamp: June 25, 2010, 12:51:41 am
content: Altium is the standard in AustraliaWhat sites have you used?Typing Altium into Seek gets quite few hits, let alone other key words like PCB design.Atmel only gets one hit in NZ, so if you limit yourself to AVR you are in for a tough time. try "microcontroller" in general.Dave.

author: MAN
author_rank: Newbie
timestamp: June 25, 2010, 11:49:25 am
content: Dave, thanks for reply & for hints!I have used for seach - seek.com.au. I have typed "Atmel", "AVR", "microcontroller" etc. You are right - "microcontroller" gives some advertisements, but most of them desire ARM based microcontrollers. If internet reflects Australian job market correctly I had better learn new cores or try to find a PCB development job. I'd like to hear Australian engineers opinions. Probably somebody is employed in similar branch or well-informed about real (not internet) situation. If you are employed in embedded, write please which boards are you using and which ones are desirable now.Alexey.

author: EEVblog
author_rank: Unknown
timestamp: June 25, 2010, 11:15:37 pm
content: There is nothing to stop you going for an ARM job if you only have AVR skills. The differences are pretty trivial.Often you are not expected to have direct experience in the core in question.Dave.

author: adnan
author_rank: Newbie
timestamp: June 26, 2010, 03:12:42 am
content: You are so right
Cool engineering websites - Page 1
Forum section: electronics / general

author: kc1980
author_rank: Regular Contributor
timestamp: June 24, 2010, 05:44:21 pm
content: Hello all,As we all know, there's a tremendous amount of engineer information available freely on the internet; however, the biggest problem is actually finding these resources and weeding out the cyber-junk. I thought that it might be fun for us to share our personal favorite web bookmarks.Here's one for starters:http://www.emcesd.com/(the articles towards the bottom of the page are great)
SMD resistor code calculator - Page 1
Forum section: electronics / general

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 19, 2010, 08:48:17 pm
content: If you do not have one ....now you do ..http://www.hobby-hour.com/electronics/smdcalc.php#smd_resistor_code

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 19, 2010, 08:51:33 pm
content: if only the through hole resistor have this kind of coding, we wont be needing the calculator and the color chart.

author: RayJones
author_rank: Frequent Contributor
timestamp: June 19, 2010, 09:31:41 pm
content: The thing that amuses me about surface mount resistors was the reason for using colour bands in the first place.They couldn't print the numbers small enough.Meanwhile technology has moved on, and now optometrists are doing a roaring trade

author: Zero999
author_rank: Super Contributor
timestamp: June 19, 2010, 10:47:32 pm
content: I don't see the point in any of those calculators, I can remember the basic code.An EIA-96 chart would be very handy though.

author: charliex
author_rank: Frequent Contributor
timestamp: June 20, 2010, 02:45:27 am
content: they'd be for people who can't, or live by einstein's principle of never memorize something that you can look up. if its good enough for einstein

author: Zero999
author_rank: Super Contributor
timestamp: June 20, 2010, 08:49:52 am
content: I made no conscience effort to memorise it, it just happened. Remembering certain things is good because recalling is quicker than looking it up - I could tell you the value of a resistor before you even have chance to look at the chart.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 20, 2010, 08:59:47 am
content: Quote from: RayJones on June 19, 2010, 09:31:41 pmNop , the color bands are still a great idea ... you have " many chances " if you work with out schematic ,to recognize the exploded - burned resistance, from the color bands.

author: Unknown
author_rank: Unknown
timestamp: June 20, 2010, 09:07:33 am
content: Plus it doesn't matter how the resistor is oriented, you never have the problem that the value is facing the PCB or some other inaccessible area. I often have this problem with things like electrolytics and diodes. But this obviously is of no concern for SMD.
some help needed ...  mini SMT  transistor called as BW ?  - Page 1
Forum section: electronics / general

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 20, 2010, 05:52:00 pm
content: I am trying to repair one PCB from an Olympus digital camera .I have find the problem ... but its tiny in size ...Do you have any idea how to locate this part called as BW transistor ?1) camera & magnifier .2) camera at full Macro .. with Macro lens ... still not powerful enough. (tiny target)3) Complete PCB .To see the pictures ... do 1 right click on them ...as soon it opens ... then left click ...view image ..

author: tecman
author_rank: Frequent Contributor
timestamp: June 20, 2010, 09:15:26 pm
content: There is a 50-50 chance that the transistor is not the only blown part. Bigger question is what caused the transistor to go ? Had to be something else, since the transistor looks like it saw some excessive dissipation.Paul

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 21, 2010, 12:57:14 am
content: Paul this PCB its a working one , the most of it .Its the main power supply of the digital camera ..The current damage = does not light up the back light of the large " rear LCD screen ".The LCD was tested with another PCB and it works ..So the damage are limited mostly to this component , and if its more , it would be at the back light mini transformer .But I need to find the transistor , so to get two or three of them, and test ..

author: Unknown
author_rank: Unknown
timestamp: June 21, 2010, 03:20:39 am
content: Atthe SMD codebook(first character B), I find an NPN Philips BCW71HR in SOT-23R (reverse pin-out).
EEVBlog Merchandise - T-Shirt Quality - Page 1
Forum section: electronics / general

author: fozzyvis
author_rank: Regular Contributor
timestamp: June 13, 2010, 10:06:05 am
content: Hi all,I've been watching the blog for quite a while now, and wouldn't mind supporting it by buying a t-shirt.In the past, I've bought my fair share of t-shirts and such things, with varying quality. So my question would be to anyone who has bought one of these shirts if they're going to last a while, or are they the type that wear out after 15 times in the washing machine?I don't mind paying an extra couple of bucks, if that gives me a quality product, but I've been dissapoint one too many times in the past...

author: EEVblog
author_rank: Unknown
timestamp: June 13, 2010, 11:21:06 am
content: All the Zazzle shirts that I have got are top quality.None of them are made in China!My Flux capacitor shirt is made by American Apparel in downtown LA, and it is exceptional quality, but it is the most expensive.My 555 Timer T-Shirt is made by Hanes in Honduras, and that is a cheaper option, but it's still very good quality.And there are many other options of varying quality and sustainability.You can get any of the designs on any of the shirts, subject to the dark/light restriction thing.Dave.

author: fozzyvis
author_rank: Regular Contributor
timestamp: June 13, 2010, 11:47:25 am
content: Allright, thanks.I'll take your word for it and make an order tonight!

author: charliex
author_rank: Frequent Contributor
timestamp: June 13, 2010, 06:28:11 pm
content: "American Apparel in downtown LA"I can see them outside my apt window almost. Just out the window to the right.

author: Time
author_rank: Frequent Contributor
timestamp: June 13, 2010, 07:10:21 pm
content: WOW, nice apartment view. I am jealous.
Broken Signal Generator - Page 1
Forum section: electronics / general

author: cksa
author_rank: Regular Contributor
timestamp: June 12, 2010, 09:54:14 am
content: http://cgi.ebay.com.au/HP-SIGNAL-FUNCTION-GENERATOR-/170497804922?cmd=ViewItem&pt=AU_B_I_Electrical_Test_Equipment&hash=item27b2760a7a#ht_500wt_1117What do you reckon? Should I snap it up and hope I will be able to suss out the problem? Worth it?

author: cybergibbons
author_rank: Frequent Contributor
timestamp: June 12, 2010, 10:02:59 am
content: The service manual is available, but these really are beasts inside - really really complex.That said, if it is responding to user inputs, I would say you have a fair chance. If you don't have a scope and decent meter though, I'd get them first before taking something on like this.It's quite a high-end signal generator, personally I wouldn't need most of the features and would prefer a new, but more simple, generator.

author: cybergibbons
author_rank: Frequent Contributor
timestamp: June 12, 2010, 10:24:20 am
content: http://www.to-way.com/teqman/HP/8165A/HP%208165A%20Service.pdf

author: cksa
author_rank: Regular Contributor
timestamp: June 12, 2010, 10:31:52 am
content: I do have a scope (Rigol) and meters. Of course there's no way i need all of the features anyway, but other signal generators on ebay all seem to be more expensive (even the basic ones)!

author: Unknown
author_rank: Unknown
timestamp: June 12, 2010, 01:39:51 pm
content: I would be tempted if I had the room and it went fairly cheap (almost five days to go, so the final bid might be much higher). I don't think it contains many custom parts, so in theory it should be repairable. From the description, the digital stuff seems ok, but the defect seems somewhere in the analog section (eg. frequency generation or output amplifier). It could be something really simple like a shorted tantalum capacitor, or something harder like a subtle problem with a hard-to-find op-amp in a loop. You have to consider it a gamble, you might win (replace a $0.10 tant and be finished in half an hour) or lose and never be able to fix it.I wouldn't be worried about buying too much function generator (for a reasonable price), better to grow into something than to outgrow it.

author: tecman
author_rank: Frequent Contributor
timestamp: June 12, 2010, 02:01:28 pm
content: Manuals are available for download on agilent's site. Most of this equipment is very robust. Circuitry is usually fairly easy to troubleshoot, and most failures are a simple cap failure or similar. For the price I would go for it.paul
Time for another rant, Dave?  - Page 1
Forum section: electronics / general

author: comox
author_rank: Regular Contributor
timestamp: June 11, 2010, 08:09:35 pm
content: The Federal Government has confirmed it is considering a policy requiring Australian internet providers to retain precise data on how their users are using the internet, with the potential to include information on emails sent and — reportedly — their web browsing history:http://delimiter.com.au/2010/06/11/govt-may-record-users-web-history-email-data/

author: EEVblog
author_rank: Unknown
timestamp: June 12, 2010, 12:35:37 am
content: Oh FFS!, what next?I think I'll wait until Conroy inevitably says something really stupid and then have a go!Dave.

author: idris
author_rank: Newbie
timestamp: June 12, 2010, 10:14:32 am
content: Conroy saying something stupid? Never!People need to stop complaining about the 'nanny state' and realise the government is working in our best interests. When up to 20,000 Australians are infected by spams and scams coming through the portal, I know Conroy will be there to protect me.

author: TheWelly888
author_rank: Frequent Contributor
timestamp: June 12, 2010, 01:27:18 pm
content: Would Conroy ban Dave's phrase,"Let's blow some shit up" because it "advocates terrorism?"or "very frequent or very strong coarse language"? - you heard Dave!or "strong depictions of nudity" - the sight of Dave's bare feet in his sandals???My God, Kevin Rudd and his government sounds like the Antipodean version of Tony Bliar's New Labour Party that has fucked up my country with their hectoring, nannying political correctness. Don't let the same thing happen to Australia!

author: topari
author_rank: Newbie
timestamp: June 13, 2010, 06:33:37 am
content: Watch the demand for oversea proxy services sky rocket resulting in many of our ISP becoming little more than glorified routers. At work we extensively use VPN. No info to collect from us.
PCB assembly jigs-Any recommendations? - Page 1
Forum section: electronics / general

author: djsb
author_rank: Super Contributor
timestamp: June 13, 2010, 04:14:19 pm
content: Hi,Does any one have any suggestions for a reasonably priced (around £50-will pay more for quality) PCB assembly jig. I mainly work on eurocard (100mm x 160mm) sized pcb's but if I can buy something that takes bigger even better. It's mainly for prototype use.Thanks.David.

author: Unknown
author_rank: Unknown
timestamp: June 13, 2010, 07:31:29 pm
content: There was atopic about it recently, might contain some helpful info.

author: saturation
author_rank: Super Contributor
timestamp: June 14, 2010, 01:23:38 am
content: Can't go wrong with a PanaviseBut for small PCB and general use I find the elcheapo 'helping hands' more than adequate:In the USA, China clones are only $5.

author: cybergibbons
author_rank: Frequent Contributor
timestamp: June 14, 2010, 09:10:35 am
content: I love my Panavise - unfortunately they are very overpriced in the UK. Keep an eye out on Ebay.
Something to do with cheap multimeters - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 24, 2010, 10:02:43 pm
content: http://hackaday.com/2010/06/24/multi-multimeter-clock/

author: saturation
author_rank: Super Contributor
timestamp: June 24, 2010, 10:12:18 pm
content: Nice is it digital or analog?

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 24, 2010, 11:19:01 pm
content: The ones pictured are analog, but digital meters should work. Might need some low pass filtering. A "floating" power supply would be needed to power the meters, but I think they can share one if the negative inputs are connected together. A cheap CEN-TECH I have (now dedicated to monitoring bench power supply current, powered by a small AC adapter) uses only 0.8mA at 9v. The positive side floats about 3v above the negative input, remaining constant despite battery voltage changes, so it seems like there's a zener diode or something. That can probably be supplied using a resistor to 5v. The negative side varies, so it probably isn't too critical. A charge pump run from a PIC output should be able to run it.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 24, 2010, 11:31:40 pm
content: He needs another one meter , to use it as " Alarm " function ... ( continuity mode )

author: saturation
author_rank: Super Contributor
timestamp: June 25, 2010, 12:43:58 am
content: Thanks NiHao, but what I meant is the actual clock operation is done by a PIC 16F628A which outputs a proportionate current to read as hour, min and seconds. So its a DAC output being read by real analog gauges. So is it analog, or digital?Quote from: NiHaoMike on June 24, 2010, 11:19:01 pm

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 25, 2010, 01:53:06 am
content: I would say it's analog, just like the "analog" gauges in modern cars that are actually connected to digital logic. The interesting part is that even before the days of digital logic, tachometers actually had primitive monostable multivibratiors inside!http://techno-fandom.org/~hobbit/cars/tachack/Where the line blurs is if you had a row of LEDs arranged in an arc to emulate an analog meter. Like my idea for an add-on tachometer for the Prius (and maybe other hybrid vehicles as well) where there is an arc of LEDs for RPMs that light up blue when the engine is actually running ("squirt") and green when the engine is merely spinning ("warp stealth" or "B mode"). Other useful gauges such as battery current can also be integrated as additional LED arcs or other displays on the same board.
Electron Flow OR Conventional theory. - Page 1
Forum section: electronics / general

author: PeterG
author_rank: Frequent Contributor
timestamp: June 09, 2010, 04:41:40 am
content: I think this will be interesting. I use Electron Flow theory because it makes sense to me. However, most schools in Australia teach Conventional for some reason.For those who don't know what this is all about, if you use Electron Flow, you follow a schematic from - to + as the flow really goes. If you use Conventional, you follow the schematic from + to - (the reverse direction). The same result is achieved from both, however if you look at how things like semiconductors work, Electron Flow is the only real way of explaining how they function.

author: DJPhil
author_rank: Frequent Contributor
timestamp: June 09, 2010, 04:58:08 am
content: I'm forced to go with conventional, as it's the way the overwhelming majority of resources for the self educating hobbyist treat the problem. I often conceptualize using EF where it seems to fit better (holes? really?), and I find it somewhat natural as I've been into physics longer that electronics. If I try to go pure EF then my brain explodes too often due to the internal translation. When I learn to differentiate things like sinking and sourcing current it's hard enough for me to get it learned the right way around to begin with!

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 09, 2010, 07:00:27 pm
content: Sometimes it's better to use electron flow, sometimes it's better to use conventional flow. (Is light waves or photons? Is it better to use time domain or frequency domain?)
Improving an old analog Tone generator ..  - Page 1
Forum section: electronics / general

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 02, 2010, 07:45:25 pm
content: Before 20 years I had build the Kit of this analog tone generator ..Back in time , I was need mainly the 1K frequency , as modulation tone , so to test FM transmitters .Later on it become useful testing audio circuitry s .But I was not totally happy with it, because just setting it, at one specific frequency, was a big issue,the pot (single turn) was not that helpful ..So I decided to improve it at the max ..One new Burns 10K (10 turns) pot , made the deference ..I Did also some small adjustments ...And now my fresh improved generator , tunes smoothly at all range ..Pictures ..

author: Unknown
author_rank: Unknown
timestamp: June 03, 2010, 03:25:13 am
content: Cool hack! And nice pot.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 05, 2010, 10:01:34 pm
content: Thanks mate ..

author: Zero999
author_rank: Super Contributor
timestamp: June 08, 2010, 11:51:20 am
content: What wave shape does it give?Is it square or sine?If it's sine what sort of oscillator is it? Is it a triangle oscillator followed by a wave shaper?

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 08, 2010, 07:11:23 pm
content: It has all three " square - sine - triangle " .Three separate outputs - three volume controls .
Underwater Gps localization - Page 1
Forum section: electronics / general

author: safarir
author_rank: Regular Contributor
timestamp: June 07, 2010, 10:18:56 pm
content: Hi everyone,I was looking at the bp live feed and I notice that the rov have very precise gps location. My question is simple: How do they do that since gps signal don't go underwater ?Thanks

author: DJPhil
author_rank: Frequent Contributor
timestamp: June 07, 2010, 10:35:56 pm
content: Probably a multiple buoy receiver system that uses acoustic triangulation. The buoy's will know their location via GPS, and will use acoustic signals to communicate with the ROV in a way that somewhat mimics what GPS does with electromagnetic radiation. That's just my guess though.Here's an example articlefrom a company that specializes in this sort of equipment.
High voltage power supplies - Page 1
Forum section: electronics / general

author: djsb
author_rank: Super Contributor
timestamp: June 04, 2010, 02:22:18 pm
content: Hi,Just been watching the latest multimeter shootout video and noticed Dave using a Keithley high voltage power supply and current supply for testing the meters. What is the power supply model that's used and can anyone generally recommend a high voltage power supply? It would mainly be used to experiment with valve amplifiers and general lab use. Thanks.David.

author: rossmoffett
author_rank: Regular Contributor
timestamp: June 04, 2010, 04:05:42 pm
content: I use a Variac and whatever high-voltage transformers I have around. HV power supplies are expensive!My line voltage is on the high end (~125 VAC) so I get almost 7 VAC on my filament taps. Tubes will operate on as low as 5 VAC with no harmful effects, so that gives quite a bit of adjustment on the HV windings with a variac. About +/- 50 Volts, depending on the voltage range you're working in.

author: Simon
author_rank: Unknown
timestamp: June 04, 2010, 09:21:23 pm
content: well you could use a voltage doubler rectifying solution and maybe two of those in series if you want 1000 V if your just after low power, infact you could get as much as 1200 V, or maybe best using a proper multiplying rectifier circuit, but this only works on low power

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 05, 2010, 12:11:16 am
content: My own question would be , how to measure 2000V with one 1000V DMM ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 05, 2010, 03:36:16 am
content: Quote from: Kiriakos-GR on June 05, 2010, 12:11:16 amBuild a voltage divider.http://repairfaq.org/sam/hvprobe.htm

author: EEVblog
author_rank: Unknown
timestamp: June 05, 2010, 05:12:13 am
content: I have 4 Keithley instruments:240A high voltage PSU225 Current Source260 Nanovolt Source261 Picoamp current sourceDave.

author: Unknown
author_rank: Unknown
timestamp: June 05, 2010, 01:04:56 pm
content: Unless you are experienced in high-voltage construction, buying a HV probe would be the safer option. It's not like DMM HV probes are that expensive.
Start of  2010  Wireless Digital Clamp-On Multimeter is launching - Page 1
Forum section: electronics / general

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: June 03, 2010, 02:35:48 pm
content: ?Taipei, Taiwan?General manager Jie Der Chen of DER EE Electrical Instrument Corp., made the announcement of “Wireless Digital Clamp-On Multimeter”?WDCM for short?at Taitronics held in Taipei on Oct. 8th.http://edn.gmg.tw/article/view.jsp?aid=198963&cid=9http://www.deree.com.tw/company-profile.htm
Hardware PID Controller - Any advantage? - Page 1
Forum section: electronics / general

author: David
author_rank: Frequent Contributor
timestamp: May 31, 2010, 05:46:08 pm
content: Hi all,Does anyone have any experience in implementing a hardware based PID controller? I.e. using Op-amps? The advantage I see to it is reduced processor overhead and less complex algorithm programming, although I can see that fine tuning it (resistor values) may be quite cumbersome. Just evaluating a few of my options for a new design.Dave

author: KTP
author_rank: Frequent Contributor
timestamp: May 31, 2010, 06:09:22 pm
content: It is what the Gecko servo drive did in their G320 series of hobby drives. They now are moving to a digital PID controller approach probably because it is easier to store/recall settings and debug. The pots used in a analog PID controller will somewhat drift with age/temperature, not to mention vibration and this could be another disadvantage.

author: tecman
author_rank: Frequent Contributor
timestamp: May 31, 2010, 08:12:54 pm
content: I used analog PID controllers for years. Our company designed our own controllers and shipped thousands over the years. Around 1990 we made the switch to digital and never looked back. True it can take some cpu power to do it right, but the options available combined with no drift and perfect repeatability are big advantages.There is a lot of good analog building blocks out today. Biggest issue is part stability over time, parts matching and thermal effects. Many of our analog controllers are still out there on a lot of machinery. A solid analog controller can still outperform a digital one in certain cases. Plus you rarely have "bugs" to worry about. On the other side, more complex controllers require more complex circuitry and more pots to adjust.Paul

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 31, 2010, 09:50:50 pm
content: CPU power is way cheaper than analog parts these days. Not to mention more stable, flexible, repeatable etc. etc.Can't see any reason to use analogue these days.
yet another DS1052E thread - Page 1
Forum section: electronics / general

author: Buzz
author_rank: Newbie
timestamp: May 31, 2010, 09:38:42 am
content: I have a DS1052E in the mail, should be here tomorrow with a bit of luck.So I will ask the inevitable question of a new DS1052E owner... can someone help me out with 2.02?I have searched hi and lo for days and apart from a couple of dead links have found nothing. I am used to my 400MHz CRO so 100MHz will feel a little bit more like home when working with the RigolThanks.

author: Polossatik
author_rank: Frequent Contributor
timestamp: May 31, 2010, 10:57:38 am
content: it's all inchanging the rigol DS1052E to DS1102E using USB , the dummy guide

author: Buzz
author_rank: Newbie
timestamp: May 31, 2010, 08:48:25 pm
content: Great thanks!
Switched-Mode Power Supplies - Page 1
Forum section: electronics / general

author: David
author_rank: Frequent Contributor
timestamp: May 27, 2010, 11:38:08 am
content: Hi all,I have managed to bag my first ever electronics engineer interview next weekand one of the areas that came up in the job role was switched-mode power supplies. I understand the basic principles but have never had any direct involvement with the design of such devices. I am sure I will know a lot more by the time of the interview (in case it comes up) but has anyone got any useful tips/information on the subject?Dave

author: EEVblog
author_rank: Unknown
timestamp: May 27, 2010, 12:47:39 pm
content: Funny that, I was just contemplating doing a very quick blog on switched mode power supplies and how they differ (not so much) from linear supplies, as a filler unti lI get my butt into gear and finish the meter shootout.Doesn't mean I will, but it's on the tip of my tongue...Dave.

author: David
author_rank: Frequent Contributor
timestamp: May 27, 2010, 01:37:13 pm
content: That would be great if you did! Pretty please?As far as I am aware the main disadvantage of linear supplies is the loses caused through dissipation of the excess power.

author: Strube09
author_rank: Regular Contributor
timestamp: May 27, 2010, 01:42:06 pm
content: Dave,If you do this blog I would like to see some information regarding the feedback loops and stability issues with some switchers due to phase and gain responses of these loops.Maybe a bit much for a basic switcher blog but just and idea.Thanks

author: David
author_rank: Frequent Contributor
timestamp: May 27, 2010, 04:31:03 pm
content: Anything on power factor correction would also be appreciated!

author: Zad
author_rank: Super Contributor
timestamp: May 27, 2010, 06:09:13 pm
content: It depends how deeply you are going to be going into PSUs. As in intro level job, I would expect it to be more about designing SMPSUs around existing commercial devices rather than rolling your own. People like ti.com and linear.com have loads of data sheets and app notes that it would be good to read. That way you get familiar of what is available on the market, what the limitations and costs are etc.

author: Strube09
author_rank: Regular Contributor
timestamp: May 27, 2010, 06:57:57 pm
content: Ditto on the PFC.

author: EEVblog
author_rank: Unknown
timestamp: May 27, 2010, 10:30:46 pm
content: The idea for this was just to show beginners that switchers aren't that mysterious, and are actually are lot more similar to linear regs than you might imagine.No PFC or stability stuff, although stability might be mentioned.Was going to film it this morning before work, but have run out of time, so probably tomorrow morning.Dave.
"Rainey" Power Probe 14ch Logic Analyzer? - Page 1
Forum section: electronics / general

author: Hypernova
author_rank: Unknown
timestamp: June 08, 2010, 11:27:57 am
content: While browsing ebay for potentials deals on LA's I came across this interesting contraptionhttp://www.aracnet.com/~mcr/powerprobe.htmlBasically it promises to increase the number of channels of your scope through some triggering tricks and make it work as a 14ch LA, but with out the protocol decoder obviously.I can find hardly anything about this thing on the home page let alone google.Some how I got a feeling this won't work very well with digital scopes.

author: Unknown
author_rank: Unknown
timestamp: June 08, 2010, 12:07:34 pm
content: Yeah, I see three BNC connectors, so it probably uses the X, Y and Z (blanking) input. I haven't seen a DSO with a Z input (doesn't mean they don't exist). There doesn't appear to be any documentation available as far as I can see, so it's hard to verify. The cables seem too short to reach the Z input on the back of most scopes.The description is really limited, nothing about record length for example. My guess would be that it samples 14 channels in parallel, stores the result, and draws them on the scope screen one by one (using it as an expensive XY monitor). So what you see on the screen might be all you get in terms of record length, I don't see any buttons to zoom or scroll (or even adjust sample rate, although it might use the X output of the scope for that).

author: saturation
author_rank: Super Contributor
timestamp: June 08, 2010, 12:46:06 pm
content: The website is so poorly done I'd be very wary of even paying just to test it.When I was a student, I was strapped for a multichannel scope; so I built a multiplexer. All it did was take inputs and alternatively show each input with a DC voltage offset on a single channel presented to the scope. Like a movie, the switching was fast enough to 'fool' the eye that it was multichannel. Good enough to monitor channels up to 100kHz particularly if a continuous waveform, which was what I working on at the time.
What kind of power connector is this? - Page 1
Forum section: electronics / general

author: allanw
author_rank: Frequent Contributor
timestamp: May 24, 2010, 08:38:21 pm
content: I picked up a BK 3010A function generator off ebay but it came with no power cable. What's this plug type called so that I can buy one?If it's too blurry to tell I can try to get a better picture.

author: wd5gnr
author_rank: Regular Contributor
timestamp: May 24, 2010, 08:57:11 pm
content: I have a BK Function Generator. These were common years back. I wonder if an IEC C5/C6 would fit it? Usually they have the mickey mouse ears, but the spacing might be ok.I would be tempted to take one of those monitor extension cords (if you can find one) that had a female IEC 13/14 (whichever one is the matching part to a standard power cable) and wire it to the pins with some heat shrink. But that's me.Al Whttp://www.hotsolder.com

author: elal1862
author_rank: Newbie
timestamp: May 26, 2010, 07:41:25 pm
content: Quote from: wd5gnr on May 24, 2010, 08:57:11 pmEek!As the orignal connector doesn't look very safe by today's standards, my advice will be [dave's voice] Don't plug it in, take it apart! [/dave's voice] and solder in a proper IEC chassis. Costs pennies (or nothing if ripped out of an old PC) and it's muchsafer than any other (hap)hazard way.
Power Supply 240V to 120V - Page 1
Forum section: electronics / general

author: redek
author_rank: Contributor
timestamp: May 25, 2010, 05:18:10 am
content: I bought 2 Thurlby Thandar power supplies off ebay for cheap. The only problem is that they are set up to run off 240V with a British plug and I live in the US. The Instruction Manual gives clear modification instructions to change the voltage, which consists of changing a few wires around on the inside. Since the plug and cord are integral to the power supply I have a few options for conversion. Use a plug adapter from type G to type B, clip off the plug end and put on a type b plug, or replace the whole cord and plug. Are their any better options?Thanks

author: Varal
author_rank: Contributor
timestamp: May 25, 2010, 06:57:04 am
content: Well I personally would narrow my options to changing the whole cable or buying a plug adapter. Cutting the wire and replacing the plug may create unnecessary threat of electric shock or short-circuit plus it doesn't look pro

author: squeezee
author_rank: Contributor
timestamp: May 25, 2010, 07:36:16 am
content: If there aren't any clearance issues I'd suggest installing an IEC socket on the back panel.

author: Simon
author_rank: Unknown
timestamp: May 25, 2010, 12:00:48 pm
content: Quote from: Varal on May 25, 2010, 06:57:04 amif done properly with a good quality plug there should be no issue

author: allanw
author_rank: Frequent Contributor
timestamp: May 25, 2010, 12:06:47 pm
content: Quote from: redek on May 25, 2010, 05:18:10 amDid you buy from the seller that was selling the one, two, and three output versions at once? From topdogtest? I won the two output one, and haven't picked the package up yet. That's disappointing to hear that it'll require modification to get it to work here.

author: redek
author_rank: Contributor
timestamp: May 25, 2010, 06:24:31 pm
content: QuoteYes. They accidentally sent me the single output when I payed for the triple output. Then told be to keep the one they accidentally sent since it wasn't worth sending back. Here is the manual, the instructions are on page 7. Fuses also need to be changed. I was also thinking about using a voltage transformer, but that will cost more and not look as good.

author: allanw
author_rank: Frequent Contributor
timestamp: May 25, 2010, 06:28:17 pm
content: I just bought a $10 plug adapter from radio shack and I'll change the wiring.

author: Unknown
author_rank: Unknown
timestamp: May 25, 2010, 08:35:01 pm
content: I'd just replace the line cord / plug (if you have a suitable plug, make sure that it's grounded if the original one was). Plug adapters mainly make sense with wall warts where you can't easily change the plug, in my opinion, although a plug adapter from China is probably cheaper than a plug. A voltage converter doesn't make sense if you can just change the transformer connections.
Website Annoyances! - Page 1
Forum section: electronics / general

author: logictom
author_rank: Unknown
timestamp: May 24, 2010, 02:34:25 pm
content: Something that really winds me up is manufacturers website where you have to not only register but then wait over a week before receiving an email telling me to "please fill out the form properly" which I filled out all the required fields, why they need my address for a data sheet, who knows?Why can't companies just put all their data sheets on the website in pdf's freely without registering I don't know! Grrr pain in the arse!

author: logictom
author_rank: Unknown
timestamp: May 24, 2010, 02:40:28 pm
content: I replied with my address and UK at the bottom and I have just received an email saying thanks but they need to know which country I am in?!Last time I checked UK was a bit of a give away?! Don't know why I bother sometimes

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: May 24, 2010, 05:44:37 pm
content: The same happened to me , I just wanted one pdf about their products , and I had to write even the color of my toilet door .. so to register ( CHAUVIN ARNOUX ) France.When I see such behaviors , I am aware that they pay worthless people as advisor's .

author: David
author_rank: Frequent Contributor
timestamp: May 24, 2010, 09:17:39 pm
content: Out of interest, who were the manufacturers?

author: EEVblog
author_rank: Unknown
timestamp: May 24, 2010, 09:31:01 pm
content: Yeah, name'n'shame!I hate this too and will boycott their products from then on. Unless they have shit hot products I need then in that case I abuse them.Dave.

author: logictom
author_rank: Unknown
timestamp: May 24, 2010, 09:57:58 pm
content: The company is OmniVision, they've now fobbed me off onto someone from 2k1.co.uk as they sell some of their gear but they don't even have the specs on the site let alone the datasheet. What a mess.I picked up the cheap CMOS image sensor off ebay as they seem to pop up in quire a few image processing projects on the net and thought I would have a play about. I've emailed the guy on ebay and managed to get a prelim copy of the datasheet from him, so far he's doing a better job that OmniVision

author: logictom
author_rank: Unknown
timestamp: May 25, 2010, 11:08:40 am
content: LOL the plot thickens! Apparently now I need to sign an NDA so I can have a datasheet. Is this the norm with any other company or is this as crazy as I think?
MMCX adapter - Page 1
Forum section: electronics / general

author: dengorius
author_rank: Regular Contributor
timestamp: May 21, 2010, 05:23:20 pm
content: Hey guys, I'm looking for and MMCX adapter (an extension chord to be precise). I have an MMCX antenna that doesn't fit into a chip due to too narrow space so i need and adapter with a right angle plug at the end. So again it's [any shape female MMCX] -> [right angle male MMCX]I've been looking around the Internet for such a cable, but i couldn't find anything. I've been told those cables are hard to crimp due to high frequency (it's a GSM antenna) and that you should get one properly done, otherwise it may broke easily or not work anyway.Do you have any clue on where to find one / get one done ?Someplace in Europe would be fine otherwise I'm afraid that the shipping cost would be too high.Thanks in advance guys

author: joelby
author_rank: Frequent Contributor
timestamp: May 24, 2010, 04:13:16 am
content: A company I worked for used to get MMCX to N pigtails made up by a local company. I just found a place in the USA that lets you order them -http://www.rfconnector.com/rf-cable-assemblies.php. They supply straight and right angle MMCX with a choice of gender, cable type and length.

author: dengorius
author_rank: Regular Contributor
timestamp: May 24, 2010, 05:26:15 pm
content: Cheers mate, thanks for the help
Excessive Power Consumption of AVR - Page 1
Forum section: electronics / general

author: cksa
author_rank: Regular Contributor
timestamp: May 22, 2010, 12:02:38 am
content: I have a problem with my current ATMEGA48. It draws ~24mA (running off 4V) while doing nothing! I've even hooked it up on the breadboard with nothing connected other than the power supply rails. I've turned off most of the peripherals on the AVR by the PPR register and even sent the AVR to some sleep modes. They have reduced the power consumption by ~1mA (so it was drawing 25mA before). Clock speed is at 1Mhz (8Mhz internal resonator and CKDIV8).I have no idea what is drawing so much current. I hooked up an ATMEGA32 similarly, and without turning off peripherals or shutting down, it is only drawing 5mA.Also, I measured the impedance across the power supply rails of the AVR (AVCC and VCC hooked together), and whilst on the ATMEGA32, the impedance is in the megaohms, on the ATMEGA48, the impedance is around 187 ohms!!Any ideas?Thanks in advance,Carson

author: charliex
author_rank: Frequent Contributor
timestamp: May 22, 2010, 12:21:53 am
content: bad chip?

author: migsantiago
author_rank: Frequent Contributor
timestamp: May 22, 2010, 12:27:00 am
content: Maybe one pin is burned and it is short circuiting internally the Vdd and Vss.

author: saturation
author_rank: Super Contributor
timestamp: May 22, 2010, 11:22:21 am
content: Its clearly out of spec in quiescent current so its busted.The bigger question is why.

author: xani
author_rank: Frequent Contributor
timestamp: May 22, 2010, 01:31:42 pm
content: My bet is static elecricity ;]

author: jahonen
author_rank: Super Contributor
timestamp: May 22, 2010, 03:21:48 pm
content: All unused IO's configured as outputs and set appropriately (or if inputs, pulled up or down)? Floating CMOS-inputs tend to draw excessive currents.Regards,Janne
194 Transistor Digital Clock (no IC's) - Page 1
Forum section: electronics / general

author: Ferroto
author_rank: Frequent Contributor
timestamp: May 19, 2010, 12:14:15 am
content: Anyone ever take on a project this absurd just to say you canhttp://hackaday.com/2010/01/11/194-transistor-clock-will-blow-your-mind/

author: EEVblog
author_rank: Unknown
timestamp: May 19, 2010, 02:58:36 am
content: Beautiful, just beautiful...Dave.

author: Zad
author_rank: Super Contributor
timestamp: May 19, 2010, 03:07:58 am
content: Wow, that's a lot of work! I have wanted to build a Nixie clock for some time and I think using transistors rather than ICs would suit the ethos pretty well. I can understand why they packaged it all on one board (if ya got it, flaunt it!) but I think for practical purposes it would be better with a horizontal motherboard and slot-in daughterboards and display board. Superb though.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 19, 2010, 09:35:08 am
content: .. orf couse if you want to go really hardcore, how aboutan all-tube nixie clock

author: thedigitalprincess
author_rank: Contributor
timestamp: May 19, 2010, 10:04:21 am
content: Haha, my friend showed me that a while back. It's wonderful xD

author: Ferroto
author_rank: Frequent Contributor
timestamp: May 19, 2010, 11:36:36 am
content: Quote from: EEVblog on May 19, 2010, 02:58:36 amYa seeing someone do a project like that makes me appreciate how far we've come.

author: saturation
author_rank: Super Contributor
timestamp: May 19, 2010, 12:00:43 pm
content: I used to build things like that, all discrete parts, because that's all we had. When I began, the 555 timer was just designed, and the most often used IC was the 741 op amp. Now, you can build it, just for looks and nostalgia.Interestingly, some appliances do come with transparent cases, so you can appreciate the guts, the Pickit 3 comes to mind.

author: EEVblog
author_rank: Unknown
timestamp: May 20, 2010, 02:42:15 am
content: I wonder if he simulated that first?So easy to goof something at the schematic or layout stage.Dave.

author: saturation
author_rank: Super Contributor
timestamp: May 20, 2010, 11:33:40 am
content: Yep, older chips mostly were semiconductors and resistors, like the 555 timer. Now, many components exist inside the chip.I'd think you'd want to simulate this, there's too much that can go wrong or interact. In the clocks I've designed, all you need is tap half wave rectified step down AC mains to get a 60 Hz pulse [ in the USA] to serve as a clock signal, then the rest of the circuitry is a counter adjusted to read out in time, and the power supply.From the layout of the board, the repeating nature of the sections looks like the designer fleshed out some chips into discrete components.Quote from: shafri on May 19, 2010, 10:21:28 pmQuote from: EEVblog on May 20, 2010, 02:42:15 am