hybridfree/eevblog-posts huggingface dataset:
A simple low drop linear power supply by MIC29752 - Page 1
Forum section: electronics / beginners

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: December 19, 2016, 09:00:53 am
content: Hello,Kindly take a look this attachment.I am trying to make a low drop/ current control regulator circuit.Online circuit is available.Need to be analyze more.LM358 is using for a buffer may be.Kindly explain more, what bottom IC is used in this design.Is it a low drop high current application?

author: mariush
author_rank: Super Contributor
timestamp: December 19, 2016, 09:18:45 am
content: The opamp ( LM358) is there to help both linear regulators (MIC29752) output the same voltage and work together so that in total they can deliver more current.Each one can do up to 7.5A , together as you can see from the picture they can do up to 15A.The 0.01 ohm resistors on the output of each regulator are also important components in making sure both regulators work and it's not just one of them doing most of the work.REad the datasheet for that regulator if you want to learn more:http://ww1.microchip.com/downloads/en/DeviceDoc/mic29150.pdf

author: Kleinstein
author_rank: Super Contributor
timestamp: December 19, 2016, 10:59:48 am
content: There is a small mistake in the circuit: there should be no direct connection of the two outputs. So R3 should only go to the upper regulator.

author: jeroen79
author_rank: Frequent Contributor
timestamp: December 19, 2016, 03:41:17 pm
content: Yes, remove the link between R3 and the output of the lower regulator.Then the opamp will keep the voltage over R4 and R5 the same so that each regulator will supply the same amount of current.

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: December 20, 2016, 12:47:27 am
content: Hello Sir Mariush,Thank you to keep your eyes in this post.QuoteYes it makes sense, did you see both output are connected its non-inverting point with R3?QuoteDefinitely first one, because its adj point controls the output voltage measuring the ratio of R1 and R2 with a constant.(according to datasheet)How about the feedback capacitor on LM358, does it work for frequency dependent impedance ?It seems like , LM358 is using for just keeping the bottom ICs output at constant.

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: December 20, 2016, 01:01:44 am
content: Hello sir Kleinstein,Thank you to your suggestion.I think, if you look the opamps inverting and non-inverting inputs, it should have some differences.If we remove lower portion of R3's wire, that means the input difference will be more, that will cause unbalance situation on bottom IC's output.R3 can make a difference(connected with both output) and taking another reference from same bottom output.

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: December 20, 2016, 01:05:08 am
content: Dear Sir Jeroen79,QuoteKindly explain it more.
A small computer based on an Atmega32 microcontroller - Page 1
Forum section: electronics / beginners

author: FlevasGR
author_rank: Regular Contributor
timestamp: December 30, 2015, 03:02:42 pm
content: Hello folks,recently i got the idea of building a small 8 bit computer w/ internet connectivity. It will be based on an Atmega32 with ethernet interface and expandable ram.The reason i want to do it is mostly for fun but also to learn few things. If you have any challenge you want to add check the github page:https://github.com/meletisf/AVR-PC

author: jpmkm
author_rank: Contributor
timestamp: December 30, 2015, 03:43:03 pm
content: Sounds like a very ambitious project. Are you going to have a local display or will you need to connect to it with a serial terminal? Are you going to try to fit all your code in to the 32KB of onboard flash?Good luck!

author: FlevasGR
author_rank: Regular Contributor
timestamp: December 30, 2015, 04:28:01 pm
content: Quote from: jpmkm on December 30, 2015, 03:43:03 pmFor now im going to use a nokia LCD display since i want something which just works. Also it's simpler to build a gui for the specific screen.Regarding the space i have no idea if i can fit everything in there... I might need to change chip for larger storage in the near future

author: dom0
author_rank: Super Contributor
timestamp: December 30, 2015, 04:34:40 pm
content: Things like these aren't fun without some kind of memory protection (virtual memory for example), which has been around in minicomputers since the 70s (remember the PDP-11?). That makes toying around with your own OS just so much more fun, that I wouldn't do it on an AVRfor this reason alone. The basically non-existant IO bus capabilites of AVRs add to it. Doing stuff with minicomputers and SPI is just no fun...

author: c4757p
author_rank: Super Contributor
timestamp: December 30, 2015, 04:37:48 pm
content: Quote from: jpmkm on December 30, 2015, 03:43:03 pmHave to, unless he goes with a (probably quite slow) bytecode interpreter in flash, as the AVR can only execute directly out of flash.
A soldering station  - Page 1
Forum section: electronics / beginners

author: thannara123
author_rank: Newbie
timestamp: August 23, 2014, 09:38:16 am
content: Please advice to buy a soldering station /iorn for laptop service .

author: con-f-use
author_rank: Unknown
timestamp: August 23, 2014, 10:14:04 am
content: For laptop repair, it's smd stuff, so hot air, small irons and tweezers are handy.If you are on the cheap: Aoyue 2703A+, else Weller (e.g. WXA 2), JBC (RMST) or Ersa (i-con Vario). Preheater and BGA rework stuff might be nice, too. But that depends on what you really want to tackle.
A Solution In Search Of A Problem... - Page 1
Forum section: electronics / beginners

author: TankaaKumawani
author_rank: Contributor
timestamp: September 10, 2014, 03:14:08 pm
content: ...I'm wondering how common this situation is among new electronics hobbyists.This comes up because I was discussing project ideas with various people and thinking about them myself. Most of the ideas I have, such as a 2-4W/ch subminiature tube or solid state desk amp, solar charger or assorted kits, feel a bit pointless or overly complicated. I have all of this education and test equipment...and it all just gathers dust.How do you feel about these problems? What should I (or others) try to do in this scenario?

author: sacherjj
author_rank: Frequent Contributor
timestamp: September 10, 2014, 03:22:55 pm
content: You are almost always going to be building something at first that is easy to buy and might not be as good as something you can buy. Building it can feel pointless. However, the knowledge gained by starting from a blank sheet and building something is not pointless.An example of this is a flashing LED on a micro. For all intents and purposes, it is pointless. What does it accomplish? It makes you learn the microcontroller toolchain, and uploading it to the micro, and running it. For an Arduino, this is a no brainer. For an equivalent AVR on a circuit you built, it is less so. The result is pointless, but the path to get there is not. Once you have done it once, then building another flashing LED with that style processor IS pointless. But it might not be for a second type that is different.If you try to jump into a problem that is so complex as to be not pointless, and you never success due to difficulty, I would argue that is the ultimate pointless.
a stable trigger on any waveform? - Page 1
Forum section: electronics / beginners

author: DazA1
author_rank: Contributor
timestamp: October 06, 2014, 03:38:29 pm
content: Is it possible to get an oscilloscope to trigger on any repeating waveform?I have had no problem setting my trigger until i started looking at the voltage output of a VFD driving a 3 phase induction motor.I could see the pwm switching when i stopped the scope but could not seem to get a stable trigger at all when running. I tried HF reject on the trigger setup and adjusted the hold off but the thing would not stay still. I had hoped to view one complete cycle so i could see how the pwm changes on start up.Any ideas?

author: Torrentula
author_rank: Regular Contributor
timestamp: October 06, 2014, 04:19:41 pm
content: If you're just interested in the startup behaviour you could just single capture it (then the scope will trigger off the first rising edge).

author: w2aew
author_rank: Super Contributor
timestamp: October 06, 2014, 07:20:37 pm
content: Quote from: DazA1 on October 06, 2014, 03:38:29 pmMaybe use DC coupling on the channel to remove the "wobble" of the baseline as a start (if that's possible given your operating voltages).You should be able to use DC coupling on the trigger, with the level you have shown, and the holdoff set to something between 12 to 20ms.Of course, if you're only interested in the startup behavior, then a single shot capture is the way to go (holdoff doesn't apply).

author: DazA1
author_rank: Contributor
timestamp: October 07, 2014, 06:04:25 pm
content: Ok next time i will try DC coupling on the channel and trigger.w2aew Like your youtube videos btw. Especially the transmission line termination video i learned a lot.I think i am right in saying that the phenomenon of vfd reflected voltage is similar. In the previous image i posted the pwm signals (at the vfd) that look perfectly normal but the fast rise times of the switching IGBT's cause problems when the motor cable length is above a certain length (300M in this case). I have read up on this and they say that an impedance mismatch between the long cable and the motor, this is rectified by installing reactors. See the images below and notice the high voltage peaks at the motor, higher than the voltage rating of the motor windings (400v rms).

author: DazA1
author_rank: Contributor
timestamp: October 07, 2014, 06:08:13 pm
content: And here is the plot of the csv file i saved.The black trace is at the vfd and the yellow is 300 Meters away at the motor.
A strange compensation network on pre-amp input - Page 1
Forum section: electronics / beginners

author: igor78
author_rank: Contributor
timestamp: January 15, 2025, 12:16:20 am
content: I'm working on freq counter pre-amp. Freq range is HF and maybe VHF.I want it to be like an active probe with JFET input. The idea is straightforward - the signal goes to JFET as a source follower and then immediately into an amplifier.Clearly this has been implemented many times over, so I'm studying prior art. I found a few similar schematics where the signal is fed through some sort of compensation network? I've highlighted it on the images.I'm guessing this is the frequency compensation to improve linearity? Does not seem to be relevant here.Or is it meant to form capacitive divider and matching resistive divider with JFET gate capacitance to source? Attenuation? Why do you need attenuation here? Component values do not match in the top picture then. 10pF/gate-capacitance is not like 39k/1M ΩDC blocking capacitor on the input 470nF in one case and 100nF in the second case would have SRF somewhere within 0-50MHz band for sure, are they compensating for the SRF of the input cap?I often see caps thrown at input. Are they operating them as low value inductors on the other side of SRF? Getting 100nF cap that work to VHF will be challenging.Two level limiting diodes would add to input capacitance, why it's not a concern?

author: Kleinstein
author_rank: Super Contributor
timestamp: January 15, 2025, 09:07:25 am
content: The resistor R1 is there for protection. The parallel capacitor helps with the gain at high frequencies, kind of compensating the 39K/1M divider at least somewhat. With a frequency counter the response is far less critical than with a scope, but it still helps to have an about flat response and one would definitely not want an large extra drop to high frequencies. The 10 pF may be on the low side, but one may not want too much to still have ESD protection.The input capacitor SRF should not be that bad. At the high frequency the capacitor starts with a very low impedance and the Q is limited with X7R or similar capacitors. So even in the resonance the impedance of the capacitor can still be low compared to the amplifier input. Having a lossy capacitor here helps.

author: PGPG
author_rank: Frequent Contributor
timestamp: January 15, 2025, 11:52:00 am
content: Quote from: Kleinstein on January 15, 2025, 09:07:25 amRather compensating 39k/(2x 1N4148 capacitance) divider.

author: PGPG
author_rank: Frequent Contributor
timestamp: January 15, 2025, 11:57:38 am
content: Quote from: igor78 on January 15, 2025, 12:16:20 amIf you need DC blocking you need capacitor there.It is not important if it works at its C slope ch-c part or L slope part. Important is that it isolates DC and has enough smaller impedance than following circuits.
A strange property of lcd display? - Page 1
Forum section: electronics / beginners

author: NullAndVoid
author_rank: Newbie
timestamp: November 12, 2016, 11:49:12 pm
content: So I was messing around with those lcd displays that come out of cheap calculators, radios etc. when I put the pins in contact with my desk lamp, the digits on the display would be visible. The lamp that sits on my desk gets rather hot so I thought that had to do with it, but I kept messing around and found out the display would only be 'powered' when the lamp was on.So I created the following setup:**See attachment**The red wire is connected to the metal shell of lamp and one end of the black wire is connected to the display, the other end is not connected to anything but without the black wire connected to the display ,it wont show any digits. (the reason its showing random things is that there is no micro controller to drive it)I came up with the following assumption as to why this is happening:When the lamp is powered on, it creates some sort of electrostatic charge, causing the display to be powered but I am obviously not 100% sure.So, why does the display act this way?P.S: Was not 100% sure what section to put this in so I put it here.

author: MK14
author_rank: Super Contributor
timestamp: November 13, 2016, 12:59:07 am
content: LCD's of (that/similar) type, only need a relatively low, voltage of about a volt or so to drive them (light the segments). At virtually zero current (which is why watches/clocks can drive similar LCD's for a year or even 10, before needing replacement of the (around 1.5V to 3V or so) often tiny, battery(s) ).Long leads, near electrical mains items, such as your lamp, can easily create (pick up) stray electric fields. Hence the LCD effects you have seen.

author: VK5RC
author_rank: Unknown
timestamp: November 13, 2016, 01:04:26 am
content: See what capacitor will conduct it and what inductor will block it? Is it mains frequency or switch mode spikes?

author: ataradov
author_rank: Super Contributor
timestamp: November 13, 2016, 01:13:06 am
content: You can enable segments by simply touching them with a length of wire (just a single wire). I did that many times. LCDs are just that awesomeBut note that LCDs are very critical to DC voltages. Applying DC voltage will drastically reduce the life of the LCD.
A summary of  "electronics-primers-course-material-and-book" - Page 1
Forum section: electronics / beginners

author: ez24
author_rank: Super Contributor
timestamp: July 24, 2018, 07:50:47 pm
content: A summary of "electronics-primers-course-material-and-book"https://www.eevblog.com/forum/other-blog-specific/a/msg1341170/#msg1341170
A tool to help me learn communication protocols - Page 1
Forum section: electronics / beginners

author: Etesla
author_rank: Regular Contributor
timestamp: June 26, 2019, 02:57:36 am
content: Hi all, I am interested in learning things about common communication protocols like I2C, SPI, 1Wire, and UART. A logic analyzer is what I use to debug stuff that uses these protocols, but I often wish that I had a tool that could send arbitrary messages with arbitrary setups (baud rate settings, parity bit settings, handshaking setting) for all of these common protocols.In case this is not specific enough, I'm imagining a tool that I control from a computer over USB. On the computer end I have some GUI where I can arbitrarily set the device to output, as an example, a 5V UART communication signal with 9600 baud, 1 parity bit, 8 data bits, sending the string "hello world" with 100 ms of dead time between each of the characters sent. Even an arbitrary function generator does not really work in this case because I want the tool to know the protocols for me and set all the timing and everything up automatically. Does such a tool exist, and if so, where could I find one? Thanks!

author: mdszy
author_rank: Unknown
timestamp: June 26, 2019, 02:59:03 am
content: Sounds like theBus Pirateis EXACTLY what you're looking for.It's not GUI, but serial controlled, but it's very simple to use.
a transformer in series with the cathode and the plate on a pentode? - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: January 24, 2020, 09:53:18 pm
content: I was messing around with cathode followers and I thought of this:[ Attachment Invalid Or Does Not Exist ]and would this work for an audio amplifier?I'm guessing that it would, but what would be better or worse here than using just 1 transformer on the plate?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 25, 2020, 11:45:03 am
content: If the windings are on the same core, or if the secondaries were wired in parallel, it's split cathode feedback, most famously used by McIntosh but many others have used it to varying degrees. A common example these days being, put the cathode on the 8 or 16Ω tap, typically getting 5 or 10% voltage feedback, thus limiting the output stage's gain to about as much (below 20 or 10), and whatever the difference is, that's the local feedback ratio and therefore the reduction in distortion and output impedance.As shown, the plate is a high impedance, so the bottom transformer generates all the voltage while the top transformer drops it all in reverse, doing nothing. Give or take what the two other grids are doing.Tubes with suppressor grids, aren't worth any gain through them unless specifically made to. There are special multi-control types, 6HZ6 for example, which have a little gain this way. They have low perveance: IIRC, 6HZ6 has as large a cathode as 6V6's, but has a tiny fraction of its power output capability! Even if you had a power tube with significant g3 gain, it's shown as positive feedback, which is liable to make an oscillator. Small amounts aren't automatically out, but it's unlikely to be helpful.Screen feedback gives a fractional triode mode ("ultralinear" at the classic 43% point; other tappings are possible), which reduces plate resistance, so will force some division between the transformers. The reduced transient screen voltage does reduce power output some (IIRC, the 43% figure is supposed to be a compromise between distortion and power capacity?), and large tappings (up to 100% triode mode) reduce the power output all the way to, well, that of a triode.Tim
A tutorial on the basics of "eye patterns" on an oscilloscope - Page 1
Forum section: electronics / beginners

author: w2aew
author_rank: Super Contributor
timestamp: April 19, 2014, 04:10:28 am
content: My latest video discusses the the basics of "eye patterns" on oscilloscopes - what they are, and what they're used for.

author: miguelvp
author_rank: Super Contributor
timestamp: April 19, 2014, 04:56:41 am
content: Very nice,Thank you!Edit: Although My scope (Rigol DS2072) doesn't have a persistence settingPlus I subscribed as well

author: w2aew
author_rank: Super Contributor
timestamp: April 19, 2014, 02:43:42 pm
content: Quote from: miguelvp on April 19, 2014, 04:56:41 amThanks for subscribing!

author: SeanB
author_rank: Super Contributor
timestamp: April 19, 2014, 02:51:14 pm
content: Yes, very useful in describing how they work.

author: electronics man
author_rank: Frequent Contributor
timestamp: April 19, 2014, 09:37:01 pm
content: Brilliant one another great video

author: vk6zgo
author_rank: Super Contributor
timestamp: April 20, 2014, 05:20:43 am
content: Thanks,Alan----again,a good straightforward explanation.I have adjusted stuff using eye patterns in the past,but just followed the manual ---it never looked that hard to figure out,but I wasn't doing it all the time,so it ended up in the "one day" category.Now I'm retired,& have the spare time,I've looked it up on Google,but most of the "explanations" were of the "Gee,I'm high tech!" school,more aimed at feeding the author's ego,than teaching anyrhing.

author: vk6zgo
author_rank: Super Contributor
timestamp: April 20, 2014, 06:38:26 am
content: Strangely enough,after saying that,I've just found a bunch of good articles on "eye" diagrams,including this bloke:-http://www.edn.com/design/test-and-measurement/4389368/Eye-Diagram-Basics-Reading-and-applying-eye-diagrams

author: han
author_rank: Frequent Contributor
timestamp: April 20, 2014, 08:33:51 am
content: In the high end oscilloscope there is an clock recovery option,I wander is there any easy way to make external clock recovery, since not every data line is synchronous or the sync clock is not easy to get..e.g:USB, SDH in telecommunication.
[duplicate, please delete] - Page 1
Forum section: electronics / beginners

author: werediver
author_rank: Contributor
timestamp: March 25, 2021, 03:26:23 pm
content: Sorry for posting a duplicate message (original), the forum said there was an error posting, so I did it again. OopsThe original text follows.I think about building a microphone with a (semi-) decent ECM cartridge (maybeAOM-5024L-HD-R) and a preamp-compressor (probablySSM2166orSSM2167) for use with a computer (a laptop).Both the ECM and the preamp require power, and I'm not sure a typical computer TRRS socket is designed to supply enough current (the mentioned ECM operates at about 500 uA, while SSM2166 declares 7.5 mA [2.3 mA for SSM2167] consumption). A USB socket must be somewhere nearby, but using it for power only would yield an ugly device.At this point I'm looking at a simple to use USB audio ADC / codec and virtually the only thing I found so far isTI PCM29xxfamily of products, most of which are 2 in / 2 out devices, which feels like an overkill.My main question is:Could you recommend a more minimalistic IC I can use for a single channel microphone?I'm also a bit concerned about whether SSM2166/SSM2167 will output good quality sound. If you don't think it will and can recommend a better preamp-limiter IC or circuit, I'd appreciate that too.Thank you for your time.
A  website/forum for PCB makers? Anyone in Toronto west into PCB making? - Page 1
Forum section: electronics / beginners

author: Merlysys
author_rank: Regular Contributor
timestamp: September 26, 2015, 05:33:34 pm
content: I want to start making PCBs, bought a kit (see below) but would like to get together with locals who make them so we can share in the cost/experience. I tried this a year ago but gave up due to confusing info. There seems to be more confusion on this topic than on any other topic, maybe due to numerous opinions.Is there a website/forum you would recommend? I could do a search but if anyone can recommend a site that would be best. I know there is a forum on this site but I am seeking a more specialized site.http://www.mgchemicals.com/images/product/416K.GIF
A weird knob on old MP3 players - Page 1
Forum section: electronics / beginners

author: ppTRN
author_rank: Regular Contributor
timestamp: November 23, 2022, 11:29:36 am
content: Hi everyone,does any of you know the name, or at least were to find this old mp3 selector knob? It might come very handy in one of my project but I had no luck finding it. Even something similar would do the job, but it seems they are disappered from the whole internet!EDIT: FOUND IT!https://it.aliexpress.com/item/4000697123862.html?spm=a2g0o.productlist.0.0.59d6179cH8aW06&algo_pvid=62639b0d-92e4-4d4d-9e9c-3629fced18fb&algo_exp_id=62639b0d-92e4-4d4d-9e9c-3629fced18fb-0&pdp_ext_f=%7B%22sku_id%22%3A%2210000006104988133%22%7D&pdp_npi=2%40dis%21EUR%211.15%210.98%21%21%21%21%21%402100bde116692036606003430ed1e8%2110000006104988133%21sea&curPageLogUid=VAq9VwMmsn45Thank you very much!

author: ledtester
author_rank: Super Contributor
timestamp: November 23, 2022, 12:03:44 pm
content: I found these searching for "thumbwheel joystick":https://www.directindustry.com/industrial-manufacturer/thumbwheel-joystick-155982.htmlThey're probably expensive.Other search terms that might prove to be fruitful:- thumbwheel- spring return (e.g. spring return potentiometer)- rotary- rocker (e.g. rocker switch)- momentary (e.g. momentary rocker switch)- potentiometer / joystick
A zooming lens for BenQ W1070 Projector - Page 1
Forum section: electronics / beginners

author: TRAPTRAP
author_rank: Regular Contributor
timestamp: December 08, 2015, 02:13:01 am
content: I have a BenQ W1070 video projector, and I am trying to magnify the screen to a larger size than what I have. The screen is currently 134 inches diagonally at a throw distance of 11 feet 9 inches. I've set the manual zoom to its highest, so that's as good as it will do.The goal is to get a screen that's about 177 inches diagonally, if not another 20-40 more, if I have to stretch this for any reason. However, I'm stuck with the distance of 11 feet 9 inches. That's as far back as it can go while staying in the center of the wall. If I could put it in the corner, I would have about 17 feet, and that would be enough, but the projector doesn't have any kind of horizontal keystone correction that could make up the difference.So I'm looking for something to magnify the lens itself so that the image will appear larger on the wall without the projector having to be crooked in the corner. I've researched this myself, but I wasn't finding a lot on replacing the lens for the BenQ. The results kept coming up about replacing the lamp, and ignoring my question. I did run into someone saying something about using a GOBO lens to magnify projector screens, but I don't know a lot about that. So my question is if anyone can think of any way to do this by either replacing the lens to one that throws a larger picture from a shorter distance than what I listed, or using something to magnify the picture the lens I already have is throwing. This projector is very clear and runs in HD, so I can risk degrading the image quality a little bit, and I'm willing to spend quite a bit on this, so pricing on whatever I need will be alright.Thank you for helping me out. I'll continue looking into this myself, but I've found the users on this website to be the most reliable on any forum I've seen or been on.

author: cyr
author_rank: Frequent Contributor
timestamp: December 08, 2015, 03:11:39 pm
content: Could you use a mirror to extend the effective throw distance (project at the back wall or ceiling and bounce the image towards the screen) ?

author: TRAPTRAP
author_rank: Regular Contributor
timestamp: December 09, 2015, 12:19:36 am
content: Well, that certainly sounds like an interesting technique, but how big of a mirror would I possibly need, or how small of one. If you could go into greater detail of how this would work, or exactly what the effects would be, then, sure I think this could be something that I could do, or at least try.I've continued looking into this myself, with not a lot of luck, I'm not sure exactly what to do with the lens itself, so I might need to use something like a mirror trick or something else to basically "fake" the bigger screen effect.
A14U diode replacement - Page 1
Forum section: electronics / beginners

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: August 23, 2015, 06:12:30 pm
content: Hi, (in the famous Dave voice)I am repairing an old multimeter that had a dead current measurement. I found a blown trace, and discovered a couple of protection diodes (in parallel in reverse directions to ground) were fried. I am trying to find suitable replacements, but I am not sure the right way to do so. The old diodes are marked A14U (data sheet herehttp://www.digitroncorp.com/Documents/Datasheets/A14A,-A14F,-A14U.aspx?ext=.pdf)In this type of application what are the key things I need to look for in a replacement? I assume the average forward current of 2.5A is important, and I am guessing the non-repetitive peak surge current comes into play. I just wondered if someone more experienced could walk me through the thought process for choosing a replacement. Of course just a part number would be helpful, but I would like to learn why I should use a particular part.The parts list for the meter just lists them as low leakage rectifiers (and a Data Precision part number). I tried searching for the part number and cross reference, etc., and did not get very far.In a circuit as I describe above the idea is that if there is that in the case of overload the diode breaks down and becomes reversed biased, thus shunting the current to ground (which is what lead to the trace on the board blowing,out, but the ADC, etc of the meter being preserved). Right?I believe the meter works fine, as I removed those diodes from the circuit in a controlled environment, and the current measurements worked again. One of the diode broke (very easily) when I removed it. The other I got out intact, but I think the one that broke may have been the one that blew.Thanks for any input.

author: SeanB
author_rank: Super Contributor
timestamp: August 23, 2015, 07:45:16 pm
content: Going to be hard to get them in that glass package, but you can see if you can shoehorn a 1N5404 in place of them, or a 3A bridge rectifier with the + and - terminals shorted.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: August 23, 2015, 08:55:48 pm
content: Quote from: SeanB on August 23, 2015, 07:45:16 pmThanks for the reply. I can probably make a larger diode fit if I have to (though this little Data Precision 245 is small), but I am also trying to learn why I would pick a particular replacement.Does the higher 200A peak forward surge current of the 1N5404 ( vs 30A in the original) cause a problem in this application ( two opposite polarity diodes in parallel to ground) ?Edit: I should add these diodes are right after the mode (volts, ohms, amps) selector, but before the shunt resistors used when measuring current. It looked like somebody pumped 110v AC into it when the meter was set to milliamperes. I got the meter for $9 delivered off eBay, which was a steal.Thanks.
A17 on micron DDR4 ICs - Page 1
Forum section: electronics / beginners

author: maws6502
author_rank: Newbie
timestamp: January 30, 2023, 05:24:59 am
content: Hi,Been lurking for like 7 years, finally decided to make an account hehe. I've been working on a DDR4 based design using an i.MX8M Nano UltraLite and I've been looking at the following part numbers for a 16Gbit x8 78 pin chip:MT40A2G8JC-062E and MT40A2G8SA-062ELinks:https://www.micron.com/products/dram/ddr4-sdram/part-catalog/mt40a2g8sa-062eandhttps://www.micron.com/products/dram/ddr4-sdram/part-catalog/mt40a2g8jc-062eIn the datasheet for these parts (which seem to differ only in terms of overall package size, with identical footprint), ball N7 is listed as "A17/NF/NC, NF/NC", and the table below states: " A17 connection is part-number specific; Contact vendor for more information."While I did write to the vendor, I was wondering if anyone knows if the mentioned parts of something similar (2 Gig x 8, 16GBit, 78 pin FBGA DDR4 being used in a single rank, dual chip x16 bus with fly-by routing of addr/clk/ctlr signals for 2 devices on the same side of the board) would know if the A17 pin is indeed safe to ignore, and if it isn't, where would I even connect this pin on the controller side, as I can find no reference to it in any of the i.MX8M Nano docs (Datasheet, Ref. Manual, Hardware Design Guide) or other documents (A TI document entitled "AM64x\AM243x DDR Board Design and Layout Guidelines" has proven very useful).Additionally, I'm probably just being pedantic, but I can find no reference that states that the above part number is a single-die part other than the fact that the datasheet refers to DDP and QDPs in a way that makes it seem like these aren't either DDP or QDP, and that I can find datasheets for actual DDPs that clearly mention that they are DDP). It's probably an SDP but it'll be nice to have some reassurance.This is the first time I've touched DRAM, so apologies if I sound a little clueless!Thanks!
A4989 stepper driver with 50V? - Page 1
Forum section: electronics / beginners

author: nour
author_rank: Frequent Contributor
timestamp: September 16, 2016, 04:40:27 pm
content: Hi, I have the A4989 chip and I want to build this driver herehttp://wiki.germanreprap.com/en/handbuch/powerloluhttps://github.com/fluidfred/powerloluThis chip suppose to be rated up to 50V, but I have read somewhere that the A4989 is sensitive and even 48V is very much for it.In the datasheet they have mentioned that it can handle up to 50V and in the Github page also mentioned it can run from 12V to 50V.I want to run the the motors with 48V,I know that it is good practice not to run things near their max rated voltage,Have anyone tried this chip before up to that voltage without any problems?
A7600 burned component - Page 1
Forum section: electronics / beginners

author: snaker
author_rank: Newbie
timestamp: March 16, 2021, 06:17:57 pm
content: Hello,its nice to be part of this great community! I am trying to identify a component on a A7600 lenovo tablet.I have attached a picture and its the component that has the 5v6 on it.I dont have the schematics for this tablet but i assume that this is a diode rated at 5.6v .Its place is right after the 5v in on the usb charging port.Can someone please confirm it by the looks of it?Thanks.

author: mvs
author_rank: Frequent Contributor
timestamp: March 16, 2021, 09:23:41 pm
content: It should be a 5.6V unidirectional TVS diode / zener diode.

author: snaker
author_rank: Newbie
timestamp: March 16, 2021, 09:48:12 pm
content: Thanks a lot for the reply! Does it matter if i use zener or tvs for replacement?Edit: As i read the the underlying effect is the same for both.Thanks and have a great day.

author: mvs
author_rank: Frequent Contributor
timestamp: March 17, 2021, 12:44:29 pm
content: TVS diodes are actually zener diodes, but optimized for transient voltage suppression.If you do not find such small TVS diode, you can use zener diode. It would be advisable to check its actual breakdown voltage before you solder it to pcb. Perhaps a diode with next nominal voltage 6.2V would be better here.You can also leave it out. The tablet will be then less protected, but if you use only original charger it might be ok.

author: snaker
author_rank: Newbie
timestamp: March 17, 2021, 08:22:33 pm
content: Thanks a lot for all the information! I really appreciate your time for helping me out.
Abaqus vs Ansys vs Comsol - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: November 12, 2017, 05:45:30 am
content: What FEA software should I learn? I spend day and half reading opinions and its like going in circle,I still have no idea whitch should I choose.I give you some info about my requirements and you give me recommendation based on that.1. I dont care how much it cost2. I hate programing,I dont want to do any programming,no stupid scripts or any of that torture,I just want to use good GUI.3. I want highly polished,mature and profesional product.4. I want something that is highly popular,with big community and lots of youtube tutorials.5. I will use it mainly for acoustics,particulary high frequencie in air like 20-100KHz and in small,complex, spaces,for example,standing waves inside smartphone,or ultrasonic horn etc.If the certain software is superior in acoustics,that is big attraction point for me,I want superior acoustic simulation ability.6. Secondary uses will be airflow in tubes,thermal cooling,electromagnetic simulation of PCBs and radar phased arrays7. I love Solidworks,I want Solidworks like FEA equivalent.I love solidworks becose its easy to learn,intuitive,polished,popular,profesional and powerfull.I want the same,especialy easy to learn from my FEA.Solidworks is easiest to learn software in its class,that is big profesional powerfull CAD.Likewise I want easiest to learn big profesional FEA.I want the software to be like FEA brother of Solidworks.EDIT: I want to also mention that I absolutely love the documentation and tutorials build into Solidworks! For most part I dont even need book or watch youtube,the tutorials inside are already so good and there is so many of them,I just love it! Its absolute godsend from perspective of noob,its so easy to learn,I would like my FEA software to be the same,I really dunno,Ansys or Abaqus,whitch one is like Solidworks?
ABB REM620 Nominal Current and Modbus communication - Page 1
Forum section: electronics / beginners

author: Voulez
author_rank: Newbie
timestamp: April 15, 2025, 09:36:45 am
content: Hello everyone,I have question about nominal current configuration for ABB REM620 protection relay. I can't find where I can configure nominal current (PCM600) because for phase current measurements units are "xIn". Also I am using modbus protocol for communication with my PCS7.Thanks in advance,
ABB SEN Plus  - Page 1
Forum section: electronics / beginners

author: Voulez
author_rank: Newbie
timestamp: May 23, 2025, 07:19:45 am
content: Hello everyone,Has anyone worked with ABB SEN Plus low-voltage switchgear? I can't find any manuals for the switchgear or its components. I'd like to know what they use for diagnostics—something like Siemens' Simocode—and whether there is support for the PROFINET protocol for communication?

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: May 26, 2025, 11:02:58 am
content: Here you may find some information.https://library.e.abb.com/public/2ab046dcf20a4d50a56e6bd622d4738b/9AKK107680A4083_Brochure%20SEN_Plus_REV%20B%20EN%202024.pdf?x-sign=4o2WcCJ4ClrNDC6111c2trU7JqczTijbtm%2FOm5TCIFI1T83UWYmme7wOl5ICBaBP
About DDR4 CLK Signal Termination - Page 1
Forum section: electronics / beginners

author: ESR30
author_rank: Newbie
timestamp: August 15, 2022, 02:17:28 pm
content: Hi.I would like to know how to terminate the DDR4 CLK signal.The general design of DIMMs is to use the VDD plane as the signal return, so the termination is also connected to the VDD.However, if the GND plane is used as the signal return, should the termination be connected to GND?Or should it be connected to the VDD as in the case of DIMMs?Thanks.

author: m k
author_rank: Super Contributor
timestamp: August 20, 2022, 01:18:40 pm
content: Less noisier is obviously better so low side by intuition.But since intuition is what it is I'd go with the manufacturer.Time is also a bit difficult to inject in regular intuition, specially when it is very short.Ideal concepts like GND may also be very different when observed time window becomes short enough.
About power supplies - Page 1
Forum section: electronics / beginners

author: thememo
author_rank: Newbie
timestamp: January 27, 2017, 01:28:04 am
content: Hello , i am studying electronics engineering and this is my 1st year, as i beginner i want to ask one question about power supplies...This question may be funny to youAlso this is my homework but don't worry i don't ask what is that ... how is work... etc.My lab Prof wants a report about ' what is the difference between power supplies with details' . Actually i am about to finish this report i explain at great length: number of channels, maximum power& voltage&current limits, noise effect, resolution , programmable capabilities etc. But i am confused about one subject - Why we need different level outputs? If we compare Rigol DP832A and DP821A power supplies , one of them gives 30V/3A x2 and second of them gives 60V/1A & 8V/10A . I think it can not be the only reason to choose to have high current or high voltage, am i right? What is the reason of this difference ? Also if we use op-amp , we may need two voltage level like +12 and -12, how can give this voltages to op-amp with Rigol DP821A because it's max voltage level is 8. Obviously i confused about this issue and i don't find sufficient information. Thanks for all reply...

author: helius
author_rank: Super Contributor
timestamp: January 27, 2017, 03:54:33 am
content: Quote from: thememo on January 27, 2017, 01:28:04 amIt pretty muchisthe only reason. It appeals to users who want the option of higher voltage, and higher current, without buying two separate power supply units. You could test a 60V VFD at the same time as a 10A battery charger, for example.QuoteYou can use a single output of the supply with a "virtual ground" circuit to power an opamp.

author: jeroen79
author_rank: Frequent Contributor
timestamp: January 27, 2017, 08:35:04 am
content: There are different power supplies for the same reason that there are different cars.Opamps often don't perform well near their supply voltages. If it has to work near circuit ground this can be a problem.By connecting the negative supply to a lower voltage you get around this.

author: bitseeker
author_rank: Super Contributor
timestamp: January 28, 2017, 04:59:35 am
content: Two reasons: requirements and resolution.1. Requirements: If you have a circuit that requires 50V, then an 8V power supply isn't going to work. Similarly, if you have a circuit that requires 10A, but your power supply can only provide 2A, then it isn't going to work.2. Resolution: Digitally controlled power supplies use a DAC to set the output voltage and current. A DAC has a limited resolution (e.g., 1024 steps for a 10-bit DAC). The wider the range that must be supported by the power supply, the larger change each step of the DAC has on the output and, hence, less resolution (e.g., 1024V power supply controlled by a 10-bit DAC yields a very coarse resolution of 1V per step).These reasons (along with cost) are also why every power supply isn't 1000V and 1000A. You choose the range to fit the requirements and resolution for the task.
About Sample & Hold circuit - Page 1
Forum section: electronics / beginners

author: gagagazi
author_rank: Newbie
timestamp: August 28, 2023, 11:55:24 pm
content: I am trying to study a Sample&Hold Citcuit， as shown in Fig.1, Vosc- and Vosc+ are the signals (opposite signals) that control J3~J6 generated by the pluse generator respectively, and the in Fig.2, my understanding It is when J4 and J5 are closed at the same time, the voltage of point VM+ should be the input voltage V+, but I don't know why, when I simulated in LTspice, the voltage of VM+ is almost the same as the signal Vosc- (as shown on the left side of Fig.1), I don't know what caused this, is there any solution? Thank you so much.

author: gagagazi
author_rank: Newbie
timestamp: August 28, 2023, 11:56:00 pm
content: fig.1

author: gagagazi
author_rank: Newbie
timestamp: August 28, 2023, 11:58:09 pm
content: Fig.2

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: August 29, 2023, 02:23:26 am
content: It is probably because VM+ isn't connected anywhere.In the original schematic one end of R1 is at virtual ground (through the op amp), which would make the right side of Ssamp1 be at 0V when the switch is open. This doesn't happen in your simulation, so you probably just get a capactively coupled version of the gate signal out. The solution is probably to add the rest of the op amp circuit.

author: gnuarm
author_rank: Super Contributor
timestamp: August 29, 2023, 02:36:48 am
content: Quote from: EggertEnjoyer123 on August 29, 2023, 02:23:26 amThe end of R1 you say is at a virtual ground is not, because the inputs of the op amp are wired oppositely to what I would expect. Op amps generally use negative feedback. But, it makes sense to assume this is just a typo.

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: August 29, 2023, 03:32:10 am
content: Quote from: gnuarm on August 29, 2023, 02:36:48 amOh, I didn't even notice that. But you're right, it's probably a typo.
About TDS744A - Page 1
Forum section: electronics / beginners

author: Ilker
author_rank: Newbie
timestamp: October 05, 2020, 10:12:59 pm
content: Hello guys, I have purchased TDS744A from ebay with everything it cost about $430 dollars. I am planning to use this scope to improve my understanding about electronics, and use it for coming up project.I have done most of the test on the scope and it pass most of the test but the Processor fails. Everything else and channels looks like they are working condition. Now I start thinking that if i pay too much for this and if i should return it because of this Processor failure. It seems "dsp68klnMemTest" is the reason it fails. how hard to fix this sort of problem on these kind of scopes? I would appreciate your suggestions.I also open up the unit and i see there is so much dust build up. I am planning to clean the unit and redo the tests again. I have seen some capacitors which are not tantalum ones on the first board. If you suggest me to keep this scope , do you think i have to replace this capacitors ? if yes what kind of capacitors i should use?

author: james_s
author_rank: Super Contributor
timestamp: October 06, 2020, 12:09:57 am
content: These are great scopes if you have the space for them. The most common fault on the older ones is leaky surface mount electrolytic capacitors, they are on almost all of the boards. you should turn it off and closely inspect everything, do not run the scope until you have replaced these capacitors if any of them are showing signs of leakage. The electrolyte is corrosive and voltage will greatly accelerate the corrosion of traces and component leads, it makes a big mess that is a lot of work to fix.
About the polarity of capacitor  - Page 1
Forum section: electronics / beginners

author: rxxbxyhxxb
author_rank: Contributor
timestamp: May 28, 2014, 06:39:42 pm
content: Hi guys,I haven't understood how to use the polarity capacitors.There are 2 voltage double circuits.I can understand this form.For this form, the current flows in the direction of the arrow through the polarity capacitor when the positive half cycle. Does it damage the capacitor?I'm a little unclear in this circuit analysis.

author: c4757p
author_rank: Super Contributor
timestamp: May 28, 2014, 06:53:48 pm
content: If you lift the negative end of a polarized capacitor, current will flow "backwards" through it, but it is still biased forwards as long as the positive end can rise too. This is because the current through a capacitor is determined by the change in voltage, not the absolute voltage.'Now - thereisone potential problem. If the circuit starts up while the voltage coming in is positive, itwillbe briefly reversed until the waveform switches and the circuit stabilizes at its correct operating point. That's generally fine with aluminum electrolytics, as the wet construction allows them to "repair" brief reverse-polarization damage when switched back around the right way. Don't do it with a tantalum, though...

author: dajt
author_rank: Contributor
timestamp: May 28, 2014, 09:55:01 pm
content: Coincidence - I saw that circuit earlier this week and had exactly the question. Then I forgot about it.

author: rxxbxyhxxb
author_rank: Contributor
timestamp: May 29, 2014, 06:58:16 am
content: Quote from: c4757p on May 28, 2014, 06:53:48 pmThank you very much.
About to graduate, questions - Page 1
Forum section: electronics / beginners

author: etstudent
author_rank: Regular Contributor
timestamp: November 27, 2012, 11:52:52 pm
content: I am finally at the end of my ET program! 1 more exam, should be done by the weekend. Anyway I'm going to continue my education and go for my AAS degree in electrical/mechanical systems and maintenance. My question is I need to find something while I'm doing more school. Do you think I will be able to find something that pays on the low end like around 15 or 16 an hour with a ET career diploma? Thanks for any help.

author: EEVblog
author_rank: Unknown
timestamp: November 28, 2012, 12:00:17 am
content: Knowing the country and city you are in help a bitDave.

author: etstudent
author_rank: Regular Contributor
timestamp: November 28, 2012, 12:29:08 am
content: Quote from: EEVblog on November 28, 2012, 12:00:17 amOh sorry I thought I included that, its NJ.

author: SeanB
author_rank: Super Contributor
timestamp: November 28, 2012, 04:54:45 am
content: Put it in your profile.........