hybridfree/eevblog-posts huggingface dataset:
Cheapest way to get a clean, non standard clock frequency? - Page 1
Forum section: electronics / beginners

author: Kronkulus
author_rank: Contributor
timestamp: August 02, 2023, 01:26:21 am
content: Hello!I'm attempting to replicate a BPSK transceiver that we use at work, kind of for fun but once fleshed out would be useful to the company. It's carrier frequency is 132kHz. The medium is wire, not EM waves or light. I planned on using a dual D flip flop configuration to generate a ÷ 4 and both the in phase and quadrature oscillator, as seen in "Quadrature Oscillators" by devttys0 on YouTube. I'm struggling to find a way that's not 20 bucks to generate a non-standard oscillator frequency (528kHz because of the divide by 4). How would someone experienced in the industry go about generating a clock you can't just get in a standard crystal or oscillator, thats good enough to use as a local oscillator? Maybe I can use a standard part and I have unrealistic restrictions placed on the accuracy of the carrier frequency? Any resources/advice is appreciated!Thanks!

author: Martian Tech
author_rank: Regular Contributor
timestamp: August 02, 2023, 02:59:24 am
content: 8.448MHz (which is a standard clock frequency) divided by 16.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 02, 2023, 03:20:34 pm
content: Cheaper than a decent crystal> DSC8001BL5 from microchip.

author: langwadt
author_rank: Super Contributor
timestamp: August 02, 2023, 05:37:23 pm
content: at such a low frequency, a cheap mcu

author: AndyC_772
author_rank: Super Contributor
timestamp: August 02, 2023, 07:49:25 pm
content: Programmable PLL? Something like a CY22393?

author: Bud
author_rank: Super Contributor
timestamp: August 02, 2023, 09:21:31 pm
content: 20 bucks is peanuts for something that may be useful to your company.

author: David Hess
author_rank: Super Contributor
timestamp: August 03, 2023, 12:08:27 am
content: If you do not have a convenient frequency source already, then are inexpensive DDS ASICs.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 03, 2023, 10:51:45 am
content: and tax deductable!

author: MathWizard
author_rank: Super Contributor
timestamp: August 07, 2023, 12:05:17 am
content: How accurate does it have to be, is it just 1 project or mass production ? At those speeds, what about just a 7555 timer, or a 2 BJT multi-virbrator, or CD4000 series multi-vibrator ?
Cheap/free alternate for Proteus  - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 20, 2018, 09:56:30 pm
content: Hi,I want to do some basic experiments regarding electronics, like working with Resistors, Capacitors, using Transistors, Logic ICs etcProteus is wonderful software but its too expensive, I was looking for if someone has good experience with some cheap or free software.That would be plus if it could do more than I wished above.Thanks.

author: ataradov
author_rank: Super Contributor
timestamp: August 20, 2018, 10:07:32 pm
content: LTSpice. It is not exactly the same thing, but may be useful, check it out.

author: hugo
author_rank: Regular Contributor
timestamp: August 20, 2018, 11:50:33 pm
content: "Falstad" an online circuit simulator, you'll learn enough to be "dangerous":https://www.falstad.com/circuit/

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 21, 2018, 03:08:50 pm
content: I found different alternatives here, if any body has experience and can rate some.thanks
cheapo chinese component tester issue? - Page 1
Forum section: electronics / beginners

author: p.larner
author_rank: Frequent Contributor
timestamp: January 06, 2024, 09:53:59 pm
content: i have one of the cheap chinese component testers with the 2 row lcd readout,if i measure an inductor,one that looks like a 2w resistor it reads fine ie 1uh,if i try and measure my roller coaster inductor it just reads as a resistor no matter where the roller is adjusted to along the coil,is it faulty?.

author: wasedadoc
author_rank: Super Contributor
timestamp: January 06, 2024, 09:57:18 pm
content: There are only 3 possible faulty items:1. The roller coaster inductor.2. The measuring device.3. The user.

author: Jwillis
author_rank: Super Contributor
timestamp: January 06, 2024, 10:44:13 pm
content: It's the automatic function of the tester. Those testers usually work at 1Khz which may be far to low to create any reactance for the tester to detect. Not sure if I'm wording that right. Butit does have something to do with the test frequency on very low value inductors. This can happen on more expensive testers unless set from auto to manual and/or increase the frequency of the test higher than 1Khz.
Cheapo ebay ESR meters - Page 1
Forum section: electronics / beginners

author: slowpoke
author_rank: Contributor
timestamp: October 20, 2014, 07:59:06 am
content: Hello folks.I'm in need of esr meter so been snooping around ebay and found there are plenty of those caseless esr meters.Are they any good ? I have watched some videos that pit them against "proper" esr meters and they did well.However in none of the videos i watched they've been tested in circuit.So my questions are:1. Are they worth it ? (10-20 quid) Can something better be had for this kind of money ? (Dont think so, but one can hope, right ?)2. Will they work in circuit ?3. Can they do big caps ? (Amp filters and such)

author: cpt.charlie
author_rank: Contributor
timestamp: October 21, 2014, 11:01:04 pm
content: Normally you can't measure a capacitor in circuit (unreliable measurements), BTW all these cheap meters are a copy of the avr transistortester, there is an interesting thread about it:https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/And yes, for 20$ these toys are worthy, but make sure the caps are discharged before measuring something, this design has no input protection..Cheers.
Chebyshev Transfer function (odd order) - Page 1
Forum section: electronics / beginners

author: Dmeads
author_rank: Regular Contributor
timestamp: September 13, 2020, 09:33:24 pm
content: Hullo!I working on Chebyshev filter for the first time using this link:http://www.simonbramble.co.uk/techarticles/active_filters/active_filter_design.htmIm working through the design of the 5th order HP Cheby (1dB ripple passband) with fc = 1 KHz.I am trying to figure out the denominator for the normalized transfer function. Since the filter is 5th order, it has two 2nd order stages cascaded with a 1st order stage. The first order polynomial is where i am having trouble.The pole tables say that the real pole for a LP cheby with 1db ripple 5th order is -0.28http://www.simonbramble.co.uk/techarticles/active_filters/active_filter_pole_locations.pdfGiven the Transfer function for a single pole normalized (Resistors/caps set to 1) HP RC filter: 1/(1 + 1/s)if we replace the 1 in the denominator with the real pole from the table: -0.28 + 1/s = 0then invert: -3.5714 + s = 0and divide all terms by -3.5714 to normalize: 1 - 0.28s = 0is (1 - 0.28s) the third polynomial in the denominator for the normalized transfer function (in additon to the two second order polynomials I already found were correct)?Thanks,-Dom

author: Dmeads
author_rank: Regular Contributor
timestamp: September 13, 2020, 10:28:05 pm
content: actuall if the pole is at s = -1/(R*C),then the 1st order polynomial would be (s + 0.28).than answers my question never mind

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 13, 2020, 11:38:11 pm
content: Yeah that.I don't worry so much about the polynomials, as they're a solved problem, and there are calculators to transform their solutions into the approximate RLC values I need (that, because of factors not accounted for, often need further tweaking anyway). I'm satisfied with knowing the underlying mechanics: poles on a circle/ellipse/etc. for the various conditions, or some variation on that for other purposes (there are many other possible optimization goals; some even just arise from what's convenient in a given topology).But I will add in regards to that, you can get a 3-pole single stage pretty easily. The values are screwed up, it's not simply putting an RC in front of a 2-pole stage; but they can still be calculated, and have enough freedom to allow for most (all?) Q factors a stage might need.http://sim.okawa-denshi.jp/en/Fkeisan.htmNote that the response still depends on source impedance, so it may be desirable after all to put a buffer in front, which still ends up needing 3 op-amps; but this is better than the 4 that would be needed for a buffered 1/2-pole chain. Heh, also not that it saves much in practical terms, given that amps come in duals and quads, but this can be helpful in stereo/multichannel systems.Tim
Check for High frequency oscillation? Distortion Pedal - Page 1
Forum section: electronics / beginners

author: Marchalis
author_rank: Newbie
timestamp: June 15, 2025, 05:01:50 am
content: Hi,I've been busy designing my own version of a distortion pedal, and have been using audio software to check and fix any high frequency noise/oscillation Spikes.But it has left me wondering if I need an oscilloscope to check beyond 20kHz.I noticed that when there was a problem, it usually spiked in a few areas from 5-15kHz. It's all looking flat with a smooth noise floor when pushed.I'm using tl072 Op Amps, if that somehow makes a difference....Thanks for any advice

author: BillyO
author_rank: Super Contributor
timestamp: June 15, 2025, 05:20:36 am
content: An oscilloscope would be the instrument of choice for this. As well, a modern scope will provide functionality, like frequency response analysis and FFT analysis, that will greatly enhance your interests in audio/guitar/music electronics.I can strongly recommend the Siglent SDS804X-HD. You will get years of useful information from it about your projects.
check of circuit diagram - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: January 21, 2020, 12:49:40 pm
content: hi i am thinking of building this for fun and expand my knowledge of smps but i think i found a error I've highlighted the problem cap i think it should be an x2 cap probably 275v 0.47uF but unless im reading this wrong 1kv 0.47n unless its a big disk cap the nearest i have is 1.6k 4n7 but kv seems a bit on the huge side ?

author: glinjik
author_rank: Regular Contributor
timestamp: January 21, 2020, 03:53:42 pm
content: ok think I've sussed it out myself 1kv is the part code 1.4n is the value its the blue type disc caps bit confusing on the diagram live and learn

author: Vovk_Z
author_rank: Super Contributor
timestamp: January 21, 2020, 04:12:19 pm
content: No, not X2. I think there isn't errror. It's snubber circuit, rated voltage is 1 kV or more, 4700 pF capacity.You can check youself at some FSDM311 related application notes.

author: Gyro
author_rank: Super Contributor
timestamp: January 21, 2020, 04:30:06 pm
content: Quote from: glinjik on January 21, 2020, 03:53:42 pmThe 104 code is 100nF, not 1.4nF (it stands for 10 followed by 4 zeros pF).For 4n7 you want a code of 472 (47 and 2 zeros pF).

author: glinjik
author_rank: Regular Contributor
timestamp: January 21, 2020, 07:12:33 pm
content: another question at L1 10uhn is this supposed to be 10uh?

author: Gyro
author_rank: Super Contributor
timestamp: January 21, 2020, 07:28:20 pm
content: It looks like it, Henry is upper-case by the way... 10uH.

author: glinjik
author_rank: Regular Contributor
timestamp: January 22, 2020, 04:29:52 am
content: thank you i WilL tRy tO RemembEr tO uSe caSes CoRectLy

author: glinjik
author_rank: Regular Contributor
timestamp: January 22, 2020, 11:16:18 am
content: Hi can someone tell me if I've got this filter correct not the values just the wiring

author: Vovk_Z
author_rank: Super Contributor
timestamp: January 22, 2020, 11:50:21 am
content: No, it is not correct. And I don't see a reason to design your own filter (they are not a secret now, but I'm not sure how it is in Russian Federation now).

author: glinjik
author_rank: Regular Contributor
timestamp: January 22, 2020, 12:21:39 pm
content: i won't answer that smart comment, this is an electrical forum not a place for cheap political digs

author: glinjik
author_rank: Regular Contributor
timestamp: January 22, 2020, 05:55:46 pm
content: Well i decided to add a choke to the circuit after a bit of reading i came up with this i plugged it in for the first time and no bang put the fluke across the bridge rectifier 116vdc scary stuff a transformer at 12v is one thing this is new territory i hope the choke is correct it's the same choke and caps that were feeding the transformer in the pc ATX so no need to calculate the choke or caps is that cheating a bit?
Check out this commutator (brushed pm dc winch motor) - Page 1
Forum section: electronics / beginners

author: electromateria
author_rank: Regular Contributor
timestamp: June 28, 2022, 04:59:41 am
content: I bought a crusty winch for $20 and tore it down and cleaned / restored it.I found the commutator kind of cool because I've never seen one like it.Is there any advantage to this placement compared to a more conventional one?

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2022, 07:49:05 am
content: Quote from: electromateria on June 28, 2022, 04:59:41 amThe brushes are on the end instead of sides which may be more convenient.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 28, 2022, 07:57:39 am
content: I've seen this arrangement in starter motors for cars. The main advantage is probably ease of assembly. If you've ever taken apart the back flange of a small DC motor and tried to put it back together you probably know how finicky it can be to push both brushes outwards while trying to push them over the commutator.From an electrical point of view it probably is a bad thing. It decreases timing accuracy of the commutation and the big difference in surface speed over the brushes causes uneven wear.

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2022, 01:22:56 pm
content: The AC motors in O-gauge Lionel trains use this configuration. I assume that a narrower but longer motor is a better form factor to put inside of a model train engine.

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 28, 2022, 01:44:29 pm
content: Looking closely, the commutator seems to have brushes on both axis - both the face and also the circumference?Edit - N/M I see that is simply the binding posts for the braided brush leads...

author: Gyro
author_rank: Super Contributor
timestamp: June 28, 2022, 03:25:09 pm
content: Quote from: Doctorandus_P on June 28, 2022, 07:57:39 amEven more finicky on a starter motor, there arefourbrushes to wrangle simultanously.P.S. It's surprising how little of the winding space is being used in the rotor, normally the passages are packed. Presumably they're getting away with finer gauge wire for intermittent use - maybe they've actually used de-rated starter motor hardware.
CHECKING A 6S BMS - Page 1
Forum section: electronics / beginners

author: silly sausage
author_rank: Regular Contributor
timestamp: January 15, 2025, 10:58:39 pm
content: Hello,a few months ago repacked my clansman prc-320 rad battery with lion colbalt 18650 cells, left it on rx as a test, long story short tthe bms did not cut off so runed he cells,i have a new bms and set of cells,is there any way to test thee low voltage cut off?,all i have is two 0-30v lab psu's,i dont want to kill the new cells,cheers tony.

author: m k
author_rank: Super Contributor
timestamp: January 24, 2025, 05:50:45 pm
content: You can mimic cells with resistors.

author: silly sausage
author_rank: Regular Contributor
timestamp: January 26, 2025, 03:10:29 am
content: what value resistors do i use?.

author: m k
author_rank: Super Contributor
timestamp: January 26, 2025, 04:53:42 pm
content: The value where voltage over single resistor is a bit under cut-off.
Checking capacitors in circuit - Page 1
Forum section: electronics / beginners

author: Crikey12000
author_rank: Newbie
timestamp: September 15, 2014, 04:23:29 am
content: I understand that to get absolutely correct readings, a capacitor must be taken out of circuit.Currently I'm more interested in just "dead or not dead" without removing from the board [testing a 5-6 year old motherboard]My method is to set my old analogue multimeter to Ohms, probe the points of the capacitor on the bottom of the board, and see if resistance goes to 0 and increases.If a cap goes to 0 and stays, it that is it? (officially shorted/dead) Or could it be affected by other circuitry

author: mariush
author_rank: Super Contributor
timestamp: September 15, 2014, 07:27:58 am
content: You can't.On motherboards, capacitors will often be connected in parallel with other capacitors. Not necessarily other electrolytic capacitors, often the electrolytic capacitors are also in parallel with ceramic capacitors of various capacitances (usually 10nF, 100nF , ~470nF etc, to reduce EMI, for decoupling etc)The meter will measure the result of all those capacitors, not just that one you want, so the results will not be accurate. Unless you can SEE the traces the capacitor is soldered to, and what's around the capacitor to be sure nothing will affect measurement, it's safer to desolder a lead (or both) and test the capacitor.

author: David Hess
author_rank: Super Contributor
timestamp: September 17, 2014, 04:37:49 am
content: Quote from: Crikey12000 on September 15, 2014, 04:23:29 amAluminum electrolytic capacitors usually fail open. Solid tantalum capacitors usually fail short.If you have some idea of the ripple current through the capacitor from the design, then a ripple voltage measurement while operating may be better than an in-circuit ESR measurement.
Checking connections and for bridges on SMT devices on adapter boards. - Page 1
Forum section: electronics / beginners

author: JoeN
author_rank: Frequent Contributor
timestamp: April 06, 2015, 10:37:12 pm
content: For soldering fine pitch SMT devices such as QFPs and QFNs to SMT adapter boards, which I use quite extensively, I have developed the following approach and I wanted to ask if this makes sense, and also if it is safe.It seems to me that the two big faults you can run into are pins that seem soldered but are actually detached and bridged pins. I look at the pins under a microscope, but I have missed very fine bridges before even under the scope, usually ones that are riding high at the top of the pins. And the microscope is not nearly as useful for QFN devices anyway. So I have adopted this method in addition to visual inspection.To check for bridged pins, after soldering the device all I do is check pin x against pin x+1 for each "side" of the device with a continuity tester, taking into account sometimes there are banks of pins for ground or VCC that are bridged on purpose. If a pin is bridged with it's neighbor the continuity tester sees this. A pin cannot be easily bridged with any other pin other than its neighbor so I only have to go down each side once for adjoining pins.To check for detached pins I have found that on pretty much every IC I have ever seen, every pin has some resistance to the ground pin. The resistance is never infinite. So I put it on the resistance measurement and check from each pin to ground. An open circuit indicates the pin needs to be touched up.So obviously for both these tests I am putting a bit of current through the IC. It's being done with a very modern multimeter - Agilent 34410A. Is that universally safe to do? Is there a better way to test this out?And I know I get a benefit here using the adapter board, it has built-in test points that a normal PCB doesn't have. I like taking advantage of that.By adapter, I mean adapters like this one, though not always this many pins:

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 07, 2015, 05:23:41 am
content: ICs with protection diodes will almost always tolerate 10mA into/out of the pins, just fine (i.e., diode-checking with respect to GND or VCC, whatever VCC domain that might happen to be). A resistance measurement (on the lowest ohms range) or diode check is usually fractional mA, and voltage limited to 2V or so.Tim

author: JoeN
author_rank: Frequent Contributor
timestamp: April 07, 2015, 05:28:08 am
content: Quote from: T3sl4co1l on April 07, 2015, 05:23:41 amLowest ohms range? What is that?My multimeter decides that for me. Maybe I should grab the spec sheet and see if it has a value for most current used in a resistance measurement...
Checking for TTL high signal with a scope? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: December 07, 2012, 07:57:06 pm
content: How would I check for a TTL high signal on a test pin using my 7854 Tek scope? Or do I need something digital? If so, what is the minimum requirement? Thanks.

author: SeanB
author_rank: Super Contributor
timestamp: December 07, 2012, 08:08:12 pm
content: DC coupled, 1V/div and see if the high level is over 3.5V. Low should be under 0.8V and the transition between should be fast, with no slow edges longer than around 2uS. A little ringing on the edges is normal or an artefact of the scope probe ground lead. W2AEW did a nice video on this recently, showing real TTL signals on his scope.

author: Chris Wilson
author_rank: Super Contributor
timestamp: December 07, 2012, 09:00:39 pm
content: Thanks Sean, can't find Alan's video, and I like to think I watch them all, don't suppose you know what it was called do you? Would like to watch that, cheers.

author: w2aew
author_rank: Super Contributor
timestamp: December 07, 2012, 09:44:32 pm
content: Quote from: Chris Wilson on December 07, 2012, 09:00:39 pmChris - here's the thread I posted it in...https://www.eevblog.com/forum/beginners/new-video-oscilloscope-probe-ground-lead-length's-affect-on-signal-integrity/
Checking rechargable batteries  - Page 1
Forum section: electronics / beginners

author: GoatZero
author_rank: Regular Contributor
timestamp: October 18, 2013, 05:30:16 am
content: 5 years ago i didnt know anything about electricity or electronics, now i do5 years ago my UPS batteries died so i teared it down to replace themToday the batteries i replaced seem to have died once again however i think something is wrong1 week ago i still could get around 10 minutes of energy and suddenly i dont even get 1 second,now i own a multimetter and an osciloscope and i was wondering about if is theres a way to check how good or bad is the battery is by using these tools

author: Psi
author_rank: Super Contributor
timestamp: October 18, 2013, 06:47:35 am
content: what is a "no break"

author: GoatZero
author_rank: Regular Contributor
timestamp: October 18, 2013, 06:53:56 am
content: Quote from: Psi on October 18, 2013, 06:47:35 amlol sorry in my country we call them no break in english its actually Uninterruptible power supply UPS, it uses 2 Lead acid batteries

author: Stonent
author_rank: Super Contributor
timestamp: October 18, 2013, 08:54:31 am
content: What country is that? Your flag looks black to me.

author: tszaboo
author_rank: Super Contributor
timestamp: October 18, 2013, 12:11:05 pm
content: Quote from: GoatZero on October 18, 2013, 06:53:56 amThis is not the first time, seriousy, where are you from?Charge the betteries with a lab psu, CC/CV mode with 0.1C for 10 hours. Measure voltage. Connect a load to it, measure current and voltage. Calculate capacity.
Checking super capacitor ratings - Page 1
Forum section: electronics / beginners

author: Wiggys.shop
author_rank: Newbie
timestamp: January 31, 2017, 02:25:37 pm
content: So I got a set of 6 new Maxwell capacitors and wanted to check the capacitance of them. I used the following procedure.https://youtu.be/DbPiQKTJntUI came up with 400 F instead of 500 F. I did the same test at a higher current of 5.1 amps and between 13 to 15 volts and got 497 F. I am guessing im not checking them correctly but I'm not sure what my mistake is.Thank you for the help.
checking voltage - Page 1
Forum section: electronics / beginners

author: slaghammer
author_rank: Newbie
timestamp: June 06, 2015, 06:26:38 pm
content: You say. If in doubt check voltage. I understand that all meters are different so if a part in a circuit is supposed to be 4v at whatplus and minus point would you call it bad.Thanks. Leo

author: SL4P
author_rank: Super Contributor
timestamp: June 06, 2015, 10:16:15 pm
content: +/- 5%max, then start to askwhy... unless the supply is marked as being better than 5%

author: picandmix
author_rank: Frequent Contributor
timestamp: June 07, 2015, 09:00:48 am
content: If you are concerned about the accuracy of your meter, then get one of the cheap 5v volt reference diodes like a LM4040 or one of the many similar devices to see how good it really is.Some meters do have internal adjusters to you can recalibrate for that particular range.
Chemical engineering student looking to develop skills in electrical engineering - Page 1
Forum section: electronics / beginners

author: georgeos
author_rank: Newbie
timestamp: August 23, 2015, 11:56:15 pm
content: Hi so as my title suggests I'm a chemical engineering student and I am wondering how to get started in the electronics space. I've been watching Dave for a few years now and I wish I could build play around with electronics in the same way he does, it has always fascinated me. He really has inspired me! Obviously I already know a fair bit of maths, and I come from an engineering background, albeit a different one. There isn't much a chemical engineer can do in terms of home projects (other than brewing beer!) but there is so much that can be done with electronics, and I love to tinker!So what's the best way to learn a lot of the theory and get started? Where is a good place to get started? Is it simply a case of picking up a textbook and learning from there, or going to the "Electronics primers, course material and books" section on the forum? Or is there something better I can do to really get into this field from where I am, a very loosely related engineering field?Thanks!

author: IanB
author_rank: Super Contributor
timestamp: August 24, 2015, 12:27:20 am
content: Hi from a fellow chemical engineer! I always had a bit of an interest in electronics since I was a child, but I never got deep into it. These days I have rekindled my interest a bit, mainly as an observer. However, I found the best way to learn things was to read online and then do experiments. The core of electronics is physics, which as a student engineer you should have no trouble with. On top of the core physics is the practical knowledge of components, what they do, how they are characterized, and how you assemble them to do useful things. This is just like chemical engineering (core physics, plus practical knowledge of equipment like pumps, compressors, heat exchangers, reactors, distillation columns etc, what they do, how they are characterized, how you assemble them to do useful things).These days there is so much information on line there is little need to buy books. To get started just brush up on your basic circuit theory (Ohm's law, DC network analysis, AC network analysis, etc.) then start studying example circuits they you may find online and trying to understand how they work. That will introduce you to non-linear components like transistors of various kinds, what parameters are used to describe them, and how they are modeled in the small signal and large signal domains.There are YouTube videos, for example by user w2aew from this forum, which provide very clear and lucid explanations of many aspects of electronic theory and practice. His videos come highly recommended.In short, just browse the forum, make note of things to research, use search engines, ask questions, and find some experiments to do. You can easily get started experimenting with just a few basic components, a breadboard and a cheap multimeter. To make anything permanent you will find a need for a soldering iron, but don't spend money until you come across something you actually need.
Cheapest VGA Controller for micro. - Page 1
Forum section: electronics / beginners

author: HardBoot
author_rank: Regular Contributor
timestamp: January 03, 2013, 08:45:54 am
content: So I want to play with programming a simple OS on a PIC32, and I'd like to drive my CRT rather than just have a serial terminal.I'd like to drive VESA 640x480@75 Hz, that's a 32MHz pixel clock... I know the little buggers are pretty quick but can they push that kinda bandwidth? I'd have a PIC32 act as a "dedicated GPU", just a dummy framebuffer, no logic beyond receiving data to spit out.I think it'll be fast enough, but I don't know if it's fast enough to have time to spare to receive data to the framebuffer, an async design will help, but it's hard to be sure.Those 128K 512K 80MHz MIPS PICs are pretty neat things, but the cost of two... kinda makes me wonder if there's a single chip solution. I want to make $15 desktop computer that can do as much as... a really old computer.I could fit 2-bit greyscale into 128KB of RAM, although 3-bit RGB would be great(super tight squeeze)... only problem is the addressing time would be higher.

author: kripton2035
author_rank: Super Contributor
timestamp: January 03, 2013, 08:58:28 am
content: I'm aware of this one :http://shop.4dsystems.com.au/vga-embedded-vga-graphics-modules/295-9005.htmlregards,

author: Jovian
author_rank: Contributor
timestamp: January 03, 2013, 11:55:31 am
content: Try a book called "Programming 32-bit Microcontrollers in C - Exploring the PIC32" by Lucio Di Jasio. It has an implementation (including full source code and schematics) for interfacing a PIC32 to a VGA monitor.Regards,Jovian.

author: mianchen
author_rank: Regular Contributor
timestamp: January 03, 2013, 05:11:55 pm
content: http://geoffg.net/maximite.htmlmight be useful to your endeavour.

author: Skimask
author_rank: Super Contributor
timestamp: January 03, 2013, 11:50:45 pm
content: Or the MAX7456.Check Sparkfun for a breakout board.

author: HardBoot
author_rank: Regular Contributor
timestamp: January 04, 2013, 01:02:55 am
content: Quote from: Jovian on January 03, 2013, 11:55:31 amThanks, I was looking for a good book.It's looking like a CPLD+SRAM is cheaper and the PIC32 acting as CPU can provide the clock... although if I did that I'd probably want to go all the way and make a universal VGA/DVI/HDMI device, ascii+graphic.

author: kripton2035
author_rank: Super Contributor
timestamp: January 04, 2013, 10:50:32 am
content: Quote from: Skimask on January 03, 2013, 11:50:45 pmthis one is nice but to overlay characters on a video signalnot really to act as a display card IMHO.
China PCB manufacturing for 0402, DFN and BGA. - Page 1
Forum section: electronics / beginners

author: johm
author_rank: Contributor
timestamp: June 25, 2016, 02:36:11 pm
content: Hello! I am facing a very small / high density design (22mm x 38mm) and have some questions:- Has anyone ever had trouble ordering a cheap PCB to china with 0402(in), DFN footprints or even modest BGA's such ashttp://www.digikey.es/product-detail/en/ams/AS1130-BWLT/AS1130-BWLTCT-ND/3028667?- Did you request ENIG, or HASL is good enough (budget sensitive project)?By default, Altium design rules for smart-prototyping.com define 6/6 mil track/space buy don't speak about solder mask sliver. Which is the main problem I'm encountering with fine pitch devices. I have to reduce the solder mask sliver parameter to 3 mil to avoid design rule errors.Any insight will be highly appreciated, thank you.

author: uncle_bob
author_rank: Unknown
timestamp: June 25, 2016, 04:02:24 pm
content: HiWhat you have is a 0.5 mm pitch BGA. That is not what most people would call "modest" in terms of layout rules. There are no fixed absolutes for any of this. It's all a matter of what your assembly process will let you get away with. That of course *assumes* you don't have standards flowed down to you that require IPC standards.When we do that sort of part, we do it with ENIG and often are forced to 4/4 rules. The bigger issue than the traces is generally the via sizes and things like via in pad. The part you have shown is indeed a small pad count so that may let you get away without as much crazy stuff in that area. The cost for the smaller vias and the tighter trace width / spacing seems to go up in lock step. If you go for one, you get the other as well.Bob

author: ovnr
author_rank: Frequent Contributor
timestamp: June 25, 2016, 04:11:31 pm
content: 0402: Works well enough for hobbyist use on chinese HASL boards. You may encounter tombstoning issues..5mm BGAs: Eeh. Your biggest issue will be fanout - you cannot,cannotdo via-in-pad on a 0.5mm pitch BGA without plugged vias, and AFAIK no cheap chinese board fabs do it. Not that I suggest unplugged via-in-pad for BGAs at all, but a 1mm BGA has more margin. You will also really want ENIG if you don't have fanout issues. For prototype work, HASL will probably work - but be prepared to do some rework.DFN is fine. 0.4mm DFN is probably going to be a bitch; otherwise, I have good experience with 0.5mm DFN and QFN on cheap HASL boards.Solder mask sliver: You will generally find that the chinese fabs will leave no slivers between fine pitch pads; all pads will be NSMD. This does result in more bridging, but careful pad and stencil design will help a lot.
Chinese 24v tweezer iron - Page 1
Forum section: electronics / beginners

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: July 01, 2019, 05:12:28 am
content: A friend, who is slowly adding to his skills by learning some basic electronics, recently bought a cheap tweezer soldering iron. He assumed that it could be connected to a cheap psu or his Weller base, but I had to inform him that this was not the case. The lead has a 7-pin 'aviation' plug fitted, and seems to be wired as two separate irons with element and thermistor. The connection PCB inside each arm is identical to that of a cheap single 'Yihua' iron. I cannot find any PSU with this plug fitted, or any info as to what it is intended to be connected to. Of course it would be 'easy' to knock up a unit or split the lead to connect to a Yihau dual output PSU with two 4-pin plugs, but that would be my task so I haven't offered yet !Has anyone seen a unit that is intended for this tool?BT

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 01, 2019, 05:43:23 am
content: Probably thishttps://m.ebay.com.my/itm/GORDAK-902-ESD-SMD-Soldering-Tweezer-Repair-Rework-Station/112154060597?hash=item1a1ce72735:g:ApMAAOSwPCVX7zEbThat pin has sensor wiring i guess for close loop feedback power control, so for diy psu he will need to study more or make feedback circuit. Or simply provide limited psu/pwm supply to avoid heater coil overheat or burn up... he probably can get cheaper buying this which is i also waiting for it to arrive.. should save working bench space with the small/portable psu unit.https://m.ebay.com.my/itm/Mini-Proffessional-Portable-YIHUA-Hot-Tweezers-Soldering-Station-For-Repairing/283507221967?hash=item420258e5cf:g:LJoAAOSwDdlc98sOThe tweezer type has 2 heater coils, so do the sensors i guess, so double the wiring should differ from normal soldering iron, ymmv,

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: July 01, 2019, 12:04:30 pm
content: Thanks Mechatrommer. The 'Gordak' unit is the intended PSU for my friend's new iron, although it seems the unit comes with the tweezers, obviously, and he must have purchased only a replacement iron. You are correct- the iron has 2 elements and 2 thermocouples and is, in effect, two irons needing a dual controller.It looks like another job for me...Incidentally- the second link shows an iron identical to his but with a plastic style 'sleeve' added over the pivot. It includes a MPU controlled PSU, probably with SMPS and is not a bench mounted unit but seems to dangle from the mains lead.Regards, BT.
Chinese chip information - Page 1
Forum section: electronics / beginners

author: zaan
author_rank: Newbie
timestamp: March 30, 2021, 04:47:04 pm
content: Hi allI am searching for the MPN or the MF of the chip I attached.Brand/MF: Marking "AV"Print Line 1: NSiP8Print Line 2: 941W1Print Line 3: X015A2Background informationThe module you can see is an add-in board of a microinverter. Microinverters typically use an RF/WIFI transmission or Powerline Communication, but we needed RS485 Modbus RTU by wire, so our manufacturer designed this module which seemed to be connected to the pads where the ESP32 used to be.The 14. pin is connected to the input of the "HVD82" (SN65) Ti RS485 Transceiver. So our thought was that it is another microcontroller that has some protocol translation on it.Research until nowI looked up every brand on lcsc.com and mouser.com starting with the letter A, which was not successful.The "AV" marking looks familiar to me.Does anyone know the brand?

author: thm_w
author_rank: Super Contributor
timestamp: March 30, 2021, 09:03:25 pm
content: Google NSIP8941 and you'll find the datasheet:https://file.elecfans.com/web1/M00/CB/D4/pIYBAF-Q5NaAFKYUAEZmuVzOCsc160.pdfNovosense3Tx 1Rx isolating IC with a built in transformer.

author: zaan
author_rank: Newbie
timestamp: March 31, 2021, 09:09:00 am
content: Thank you so much!!!I only tried the whole MPN, should have tried the segments of it.
Chinese micro-usb connectors on ebay - Page 1
Forum section: electronics / beginners

author: csheldon
author_rank: Contributor
timestamp: January 19, 2019, 10:08:12 pm
content: Hi all,I am looking into creating a project that uses micro usb connector onboard.I want to order my micro-usb from ebay.1)https://www.ebay.com/itm/20Pcs-Female-Micro-USB-Type-B-5-Pin-SMD-Soldering-Socket-PCB-Jack-Connector-Tool/202355232159?hash=item2f1d4fcd9f:g:5bwAAOSwo8pbNxbx:rk:1:pf:02)https://www.ebay.com/itm/10Pcs-Micro-USB-Type-B-Female-2Legs-5Pin-SMT-PCB-Solder-Socket-Connector/181376269980?hash=item2a3ade3e9c:g:nsQAAOSwz7JZgY-t3)https://www.ebay.com/itm/Lot-20x-Micro-USB-Type-B-Female-5-pin-SMT-Placement-SMT-DIP-Socket-Connector-DIY/153241727116?hash=item23adeb308c:g:cEcAAOSwmBhb2stR:rk:3:pf:0These "full smd" (under link1) are not so robust, and durable on pcb as those at link 2 and 3 and I cannot find any datasheets for these specific ones, and as they are all really different among many other manufacturers, my question is did anyone ever had a chance to work with ANY of these, and if it did, can you please reccomend what footprint are you using?Please help a noob in trouble,Thank you all!

author: mvs
author_rank: Frequent Contributor
timestamp: January 20, 2019, 09:17:50 am
content: It is a major problem with components sold on ebay. Sellers do not offer often dasheets or drawings of their components. You can try to design a universal pattern with larger pads and holes or buy components in advance and measure them with a calliper.Take a look at lcsc.com. They do have a lot of this chinease connectors with photos and datasheets. Perhaps you can find same models like you want to buy on ebay.

author: josip
author_rank: Regular Contributor
timestamp: January 20, 2019, 09:23:13 am
content: I used 1st one, with big side pads, so they can't break easily. Didn't know for 2nd version, I will order it right now. 3rd, I don't like.
Chinese Power Banks  - Page 1
Forum section: electronics / beginners

author: Ranger14
author_rank: Regular Contributor
timestamp: December 11, 2016, 05:13:12 pm
content: I am looking to grab a couple Chinese power banks kits off ebay and was hoping someone had some experience with some and can post the results and which one it was ??

author: Audioguru
author_rank: Super Contributor
timestamp: December 11, 2016, 05:20:40 pm
content: A lithium battery is very dangerous. Why buy a cheap no-name-brand Chinese kit designed by a person who probably knows nothing about the dangers?

author: DanielField
author_rank: Newbie
timestamp: December 13, 2016, 04:01:38 pm
content: You'd need to make sure it is safe. They can explode from overcharging if they are poorly made.I recommend paying a bit extra just to be safe.

author: retrolefty
author_rank: Super Contributor
timestamp: December 13, 2016, 05:20:35 pm
content: Here is one I just received this week. Works OK so far. Seems to include charger module and I assume proper protection features. Pretty handy 12VDC portable source.http://www.ebay.com/itm/322207932919?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Chinese TLE2426 Equivalent? - Page 1
Forum section: electronics / beginners

author: sajattack
author_rank: Contributor
timestamp: May 26, 2019, 09:18:20 pm
content: In the day of the 3 cent micro, surely there's something cheaper than a $3-4 GND reference. I tried looking on LCSC and they had multiple voltage references, but the only virtual ground reference they have is TLE2426. I know there are ways of making one out of other components, but I already have a board with a TO-92-3 footprint on it. Hope someone can point me in the right direction. Cheers.
Chip amp - Page 1
Forum section: electronics / beginners

author: Bene
author_rank: Newbie
timestamp: August 11, 2012, 06:51:23 am
content: Saw an amp online using the TDA7850 chip amp I also have been wanting to give making a PCB a try just for the experience so no I have a project. Well here is my issue I will be running a 200W 6.5" Sub in my center console so I was thinking not over kill but decent power ability. So looking at this chip and seeing that it was 2 ohm stable I figured I'd try the parallel bridged configuration but I ran into a snag I need to phase shift 180 Deg before I hit 2 of the 4 amps with out loss. my first thought was an op amp in the preamp stage with a feedback leg to the negative input but I only know of one low voltage op and that is the lm384, and it has a fixed gain so I don't think I can just phase shift with out gain .or am I wrong. My other thought was maybe a common source/common collector I believe i remember in class that is a gain of 1 and 180 deg phase shift.Also I am wondering if I am making this harder than it is. To run in parellel is easy enough but I can't swap polarities at the input of the chip since there is one input ground an 4 inputs (Can I?) So if I can't do that can I run the amps with positive to negative of channel 2 and negative of channel 2 to speaker and positive of channel 1 to speaker rather than tieing the grounds together and useing the phase shift to obtain the 2X potential.Any suggestion and maybe what components are required if any and if I have my head in the right spot.

author: Simon
author_rank: Unknown
timestamp: August 11, 2012, 06:56:46 am
content: I think you need the signal source and amp to not have a common ground, then feed the ground of the signal into one input and the positive of the signal into the other output. that way each half has opposite polarity. You can use an opamp with a gain of 1 to invert a signal, remember almost anything is possible with am op amp if you know how. If you look at the datasheet for the power amp chip you will probavbly find examples for bridge connection mode.

author: T4P
author_rank: Super Contributor
timestamp: August 11, 2012, 07:05:23 am
content: 2ohm stable doesn't mean 2ohm BTL it means 8 ohms BTLSorry to burst your bubble, but that chipamp is going to dissipate about 100W of heat at full power

author: Simon
author_rank: Unknown
timestamp: August 11, 2012, 07:08:05 am
content: Quote from: T4P on August 11, 2012, 07:05:23 amno it means 4 ohms, your putting two outputs in series so you need double the series resistance load. Yes power dissipation will be high. Personally I'd have a shot at a class D amp (not that I've ever made one)

author: T4P
author_rank: Super Contributor
timestamp: August 11, 2012, 09:16:27 am
content: Unless he only wants 100W then okay.But still lots of distortionJust buy Class D off the shelf, it's not worth it to design your own SMPS also as high wattages means high voltage also200W into 4ohms means minimum 50V requirement200W into 2 ohms means .... 25V
chip identification - Page 1
Forum section: electronics / beginners

author: Hornnumb2
author_rank: Regular Contributor
timestamp: June 30, 2020, 06:18:35 pm
content: I am trying to change the vin on a gm radio and believe the chip I have pictured is the eprom. I am using the TL866 II Plus to read but not sure what model number is of the chip. Help.

author: Hornnumb2
author_rank: Regular Contributor
timestamp: June 30, 2020, 08:16:42 pm
content: Here are the other 8pins on the board.

author: helius
author_rank: Super Contributor
timestamp: June 30, 2020, 08:39:39 pm
content: chip #1 is an Infineon power switch.chip #2 is a Microchip 24C08 or 24C16 (not sure) with a customer part number (09400464I/SN)chip #3 is an ON Semi p-mosfet.chip #4 is a Rohm power switch.Do you know how many bits the memory is supposed to have?

author: Hornnumb2
author_rank: Regular Contributor
timestamp: June 30, 2020, 09:09:44 pm
content: Thanks so much, I don't know the size of it. Should I be able to select any manufacture?

author: Hornnumb2
author_rank: Regular Contributor
timestamp: June 30, 2020, 09:49:54 pm
content: I did find just 24C08 under microchip

author: Hornnumb2
author_rank: Regular Contributor
timestamp: July 01, 2020, 04:27:55 am
content: How did you decifer those so easily?

author: james_s
author_rank: Super Contributor
timestamp: July 01, 2020, 04:49:40 am
content: The TL866 software can read the ID from a chip and tell you what it is.

author: Hornnumb2
author_rank: Regular Contributor
timestamp: July 01, 2020, 02:42:25 pm
content: Can you tell me how to do that?

author: james_s
author_rank: Super Contributor
timestamp: July 01, 2020, 08:22:40 pm
content: Connect the chip to the programmer, select something similar to what you suspect it is and click the ID button.

author: Hornnumb2
author_rank: Regular Contributor
timestamp: July 02, 2020, 12:36:48 am
content: Thanks James
Chip identification - Page 1
Forum section: electronics / beginners

author: Snake-man
author_rank: Newbie
timestamp: March 06, 2022, 11:47:12 am
content: I have an 8-foot chip that I need to identify in order to connect to a 431 programmer.This is probably a binary chip. Series 24 or 25 ..Attached are pictures of 3 chips I would be happy to help urgently.Which one is the programming chip?Thanks!!

author: Snake-man
author_rank: Newbie
timestamp: March 06, 2022, 11:48:26 am
content: This is more

author: gamalot
author_rank: Super Contributor
timestamp: March 06, 2022, 01:02:58 pm
content: 1. TJA1040https://www.nxp.com/docs/en/data-sheet/TJA1040.pdf2. TLE7259https://www.infineon.com/dgdl/Infineon-TLE7259-3-DS-v01_00-EN.pdf?fileId=5546d46259d9a4bf015a3d11e9bd5e8a3. MFI341S2313 I didn't find the datasheet ...

author: Snake-man
author_rank: Newbie
timestamp: March 06, 2022, 01:28:47 pm
content: How do I detect them in a 431 programmer like asprogramer for example?

author: gamalot
author_rank: Super Contributor
timestamp: March 06, 2022, 02:23:28 pm
content: I don't know anything about the 431 programmer, but since you mention the 24 or 25 series, I'm guessing you're looking for an EEPROM chip. It seems to me that none of the chips in your pictures look like the one you're looking for.

author: Ian.M
author_rank: Super Contributor
timestamp: March 06, 2022, 02:39:23 pm
content: None of them are any sort of Flash, EEPROM or other non-volatile memory, so none of them can or should be connected to a CH341A serial memory programmer.Still no datasheet for #3, but i did find areferenceto it:QuoteIts listed elsewhere as a "decryption chip" so certainly isn't serial memory even though it has an I2C bus.