hybridfree/eevblog-posts huggingface dataset:
nissan control units need help  - Page 1
Forum section: electronics / beginners

author: Theshop13
author_rank: Newbie
timestamp: January 09, 2024, 02:24:00 pm
content: hi all so im really new to all this and own an auto repair shop i purchased and andromeda research labs eeprom writer and am dealing with multiple rigs involved in a flood and am having a problem identifyng the id num for the chip im trying to work on any help would be great

author: coromonadalix
author_rank: Super Contributor
timestamp: January 09, 2024, 03:19:50 pm
content: well give us something to work with? we have nothing, no numbers / photos etc ...

author: Theshop13
author_rank: Newbie
timestamp: January 10, 2024, 07:06:23 pm
content: thats the problem i can barelyl see any number ill upoad a photo

author: MarkS
author_rank: Unknown
timestamp: January 10, 2024, 07:12:05 pm
content: If they're flood damaged, what can you possibly hope to achieve by rewriting the EEPROM?If the control unit is water damaged, rewriting the EEPROMs will solve nothing. The only thing I can see coming from this is to modify the VINs, thereby obtaining a clean title.This sounds fishy, especially with the lack of details.

author: Theshop13
author_rank: Newbie
timestamp: January 10, 2024, 07:15:12 pm
content: im trying to write the vin off one computer to anoter my ecm was fried im sending photos now

author: Theshop13
author_rank: Newbie
timestamp: January 10, 2024, 07:26:03 pm
content: so this particular ecu was fried becasue someone shorted the alternator wire directly to the ecm case killing it so im takeing the other one from a junk yard and have to over write the original vin with the one out of my truck because the can bus system wont let it start untill it sees matching vin number in all control unitsso to the person thinkin im doing something shady i have attached photos of the damaged truck and its vin as well as a recipt from the salvage yard i purchased the ecm from and my addresss and phone number so please dont treat everyone like a dirt bagim very new to this and the closest place to have a service like this done to me is by mail 3 days away and very expensive i just need some help walking me through some of this and somone to help me id the chips themselves

author: Theshop13
author_rank: Newbie
timestamp: January 10, 2024, 09:02:08 pm
content: by the way if i didnt say it before im using andromeda research labs complete setup i have their laptop all of their connectors and their programmer
Nixie cathode poison techniques... - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: December 13, 2016, 01:22:43 pm
content: My order fromwww.tayloredge.comarrived, so I can finally generate 170V and have a nixie to play with. Mr. Taylor was very cool.It has a dimming feature that is running at 100 Hz and does a duty cycle of 1% to 100%. You can go down to 50% or even 30% without losing a huge amount of brightness. I can see how you could use this to do an animation of moving from one digit to another if you wanted to like some of the YouTube videos I've seen of running nixie clocks.My question has to do with how to prevent cathode poisoning. I've seen the method where it cycles around to get to the digit, but I'm not feeling that so much. I know that could be done in the middle of the night, and I like that better, but I have another question: How long does it take to prevent the buildup on an unused digit? I think I'd prefer to keep the main digit displayed and rotate through the unused ones very quickly at 1 to 2 milliseconds each. Or perhaps while transitioning between two numbers, light an unused for 1 to 2 mS. How much do the unused digits need to be active per day roughly, any guesses? Any other thoughts?

author: woodchips
author_rank: Frequent Contributor
timestamp: December 14, 2016, 10:35:01 am
content: My understanding is that a clock showing hours and minutes isn't any sort of problem, the digits change sufficiently frequently. The problem comes if your clock shows date and year, then you will get problems with these digits. I have not come across and reference to the technique of rapidly multiplexing the unchanging digits as being useful.

author: jazer
author_rank: Contributor
timestamp: January 16, 2017, 09:04:07 am
content: Simple NE-2s get damaged easily enough if fed DC (flickery in months or less and dead soon after), so I think nixies might have trouble, and not just for years etc. digits.Any consensus on the best modern chips to drive nixies? Old drivers are hard to come by and lots of discretes aren't appetizing.
Nixie Clock - Page 1
Forum section: electronics / beginners

author: Aztlanpz
author_rank: Regular Contributor
timestamp: July 15, 2017, 12:22:05 am
content: Will this work?

author: skillz21
author_rank: Frequent Contributor
timestamp: July 15, 2017, 02:17:57 am
content: Try this:

author: Aztlanpz
author_rank: Regular Contributor
timestamp: July 15, 2017, 10:34:26 am
content: Anyone know if my design is functional?Thank you

author: Rbastler
author_rank: Frequent Contributor
timestamp: July 15, 2017, 11:10:26 am
content: No, you'll need pulldown resistors fro the base of the transistors.Early designs of my nixie clock didn't have them and therefore the other segments where glowing slightly, while not active.

author: Aztlanpz
author_rank: Regular Contributor
timestamp: July 15, 2017, 11:24:23 am
content: what value does the pull down resistor be.Thank you

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 15, 2017, 05:54:54 pm
content: Quote from: Aztlanpz on July 15, 2017, 10:34:26 amI think it would probably work but I wouldn't necessarily advise it. (There are lots of MPSA42 designs for cathode drivers that look a bit like yours).If you haven't already read...https://threeneurons.wordpress.com/nixie-power-supply/... read the bit about off-segment glow.Depending on the size of your tubes you might like a design that keeps your on element at ground but your floating elements around 60V.Personally I like HV5812 (and similar) drivers or you could get K155ID1 from ebay... or use Dave's approach... lots of options.What nixies do you have?

author: Aztlanpz
author_rank: Regular Contributor
timestamp: July 15, 2017, 06:19:28 pm
content: I have the IN-14 nixies

author: Rbastler
author_rank: Frequent Contributor
timestamp: July 15, 2017, 06:57:11 pm
content: Quote from: Aztlanpz on July 15, 2017, 11:24:23 amI used 15kOhm. But the final design has russian SN74141. I found a russian ebay seller, that sells the quite cheap. Using them makes everything easier and more compact.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 15, 2017, 07:13:04 pm
content: Quote from: Aztlanpz on July 15, 2017, 06:19:28 pmNiceMight be worth looking athttp://www.pvelectronics.co.uk/the kits available there are documented in the assembly instructions complete with schematics... might give you a few ideas and if you decide to opt for a Pete kit he is always super helpful. (I have no commercial connection with pvelectronics but have had tube buying advice from Pete before)
Nixie clock and 74141 - Page 1
Forum section: electronics / beginners

author: kamtar
author_rank: Regular Contributor
timestamp: April 13, 2014, 03:10:17 pm
content: Hello,Im trying to make a nixie clock as gift so I woud be happy if it could work few years without problems. I have around lots of old russians 74141 so it would be nice to use them but as i heard they wasnt very reliable (static electricity?). Its there any way how to use them with realibity (something like protection circuit?) or should i drive it with a mpsa42 transistors?sorry for my english
Nixie Tubes! - Page 1
Forum section: electronics / beginners

author: Lance
author_rank: Frequent Contributor
timestamp: May 25, 2011, 03:25:52 am
content: So an internet acquaintance of mine found 15 of them in the back of a truck in a junkyard. He happens to be in Australia. He's been messing around with them and for all but one which is a bit "whimpy" as he described it they all apparently work. I ran a quick shipping estimate and it's looking like it will cost about 100-110 Australian to ship them over. I want them, but damn! That's a lot for shipping. Anyone have any ideas? Is it worth it to spend that much on tubes like that?

author: Simon
author_rank: Unknown
timestamp: May 25, 2011, 06:50:31 am
content: it depends on what they are worth to you, I'm not use what 100 Aus dollars buys you in Australia

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 25, 2011, 08:03:42 am
content: Standard sized nixies are plentiful and cheap - 2-5 bucks. I can't imagine how you came up with a shipping cost that high as they don't weigh much , unless the tubes are still sitting in a piece of boatanchor test equipment...

author: Lance
author_rank: Frequent Contributor
timestamp: May 25, 2011, 09:24:34 am
content: That's what the fedex site spat out at me when I put in .6 for the weight in kgs. I didn't think they were that cheap. From what I've learned I thought that they were somewhat tricky to come by because they weren't produced anymore.

author: johnboxall
author_rank: Unknown
timestamp: May 25, 2011, 09:25:48 am
content: Quote from: Simon on May 25, 2011, 06:50:31 am100 litres of milkOne Australian dollar is currently worth around US$1.05 (woohoo!) or 75 Euro cents.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 25, 2011, 11:14:57 am
content: Quote from: Lance on May 25, 2011, 09:24:34 amThat's what you get when you ask people like Fedex,DHL etc. as a random 1-off customer - look at normal national Post Office services. Most offer tracking etc. nowadays

author: Lance
author_rank: Frequent Contributor
timestamp: May 25, 2011, 06:40:55 pm
content: Quote from: mikeselectricstuff on May 25, 2011, 11:14:57 amOkay then, I'll look into that.
Nixie tubes and eagle cad. - Page 1
Forum section: electronics / beginners

author: neo
author_rank: Super Contributor
timestamp: April 23, 2017, 02:32:30 pm
content: How to design a pcb for nixie tubes in eagle? I can't figure out a way to get the angle right.

author: rob77
author_rank: Super Contributor
timestamp: April 23, 2017, 03:45:56 pm
content: Quote from: neo on April 23, 2017, 02:32:30 pmwhat angle ??do it as anything else... create your component - draw the footprint as per datasheet, draw your symbol, create the component library for your nixie tube... and then do it as any other PCB using that component. there are tons of tutorials how to create your own component library in eagle (pro tip: google is your friend)

author: neo
author_rank: Super Contributor
timestamp: April 23, 2017, 03:50:42 pm
content: each pin is in a circle at 30 degree angles from each other.

author: neo
author_rank: Super Contributor
timestamp: April 23, 2017, 03:53:21 pm
content: like this. I have no clue how to do this in eagle.

author: neo
author_rank: Super Contributor
timestamp: April 23, 2017, 04:06:08 pm
content: Best i can figure out is to make a circle of the right diameter put pads on 4 sides then copy and rotate so i have found a solution.

author: Monkeh
author_rank: Super Contributor
timestamp: April 23, 2017, 04:30:33 pm
content: You should read the manual, specifically the section on coordinates, where it mentions polar coordinates.

author: boffin
author_rank: Unknown
timestamp: April 23, 2017, 06:22:54 pm
content: With Eagle (free) you're quite limited to total board dimensions. You might want to look into KiCad if you need more than a couple of Nixies.

author: neo
author_rank: Super Contributor
timestamp: April 23, 2017, 06:53:16 pm
content: Quote from: boffin on April 23, 2017, 06:22:54 pmThank you for pointing that out but eagle will be fine because the pcb will be a one off so if the fab house makes 3 identical boards as the minimum(which they do) i can use each one to hold 2.
NMOSFET input protection circuit - Page 1
Forum section: electronics / beginners

author: Teun
author_rank: Regular Contributor
timestamp: February 04, 2021, 01:26:12 pm
content: I found this circuit being used on a 150W DC-DC converter:Is D1 nessesary? And if so, why?

author: mvs
author_rank: Frequent Contributor
timestamp: February 04, 2021, 01:38:15 pm
content: MOSFET gate-source voltage is usually limited to 20V, so D1 is probably 12V to 15V zener diode.

author: Teun
author_rank: Regular Contributor
timestamp: February 04, 2021, 01:51:08 pm
content: Ok that would make sense. But the max input of the converter is 90V. I only have a 60V power supply, and at 60V the voltage at the gate is 21V. It seems to be rising linear to that point. So could it be a MOSFET with a higher Vgs then?If so it would have been easier to just adjust the voltage divider right?

author: fourtytwo42
author_rank: Super Contributor
timestamp: February 04, 2021, 01:56:40 pm
content: This looks like a fragment of a larger circuit and as such it doesn't seem to do anything by itself, what's the load ?

author: Teun
author_rank: Regular Contributor
timestamp: February 04, 2021, 02:14:24 pm
content: It's the input protection of a 150W DC-DC converter. So for this the load would be a CM inductor and then the transformer etc.Here is the typical application for the controller used:

author: mvs
author_rank: Frequent Contributor
timestamp: February 04, 2021, 02:31:57 pm
content: Quote from: Teun on February 04, 2021, 01:51:08 pmThere is no reason to drive most MOSFETs with such high voltage, even if they do have 30V Vgs max.Perhaps it was a mistake at production and 1N4148 was used instead of zener... Who knows?Do you know the part number of used MOSFET?Quote from: TeunDivider should be chosen so that MOSFET is fully open (e.g. Vgs=10V) at min input voltage.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: February 08, 2021, 02:00:26 pm
content: This diode probably limits the locking voltage at reverse polarity.
Stop audio backfeeding using diode(?) - Page 1
Forum section: electronics / beginners

author: Daan32
author_rank: Newbie
timestamp: April 30, 2020, 06:27:57 pm
content: Hi,I'm making a little 'amp box' where i'm connecting multiple inputs together internally, but how can I stop any audio backfeeding into the sources when multiple sources are connected and only one of them is playing? Backfeeding wouldn't be too good for the sources, right?I already tried using a diode, but that didn't work. However, I also don't know what diode to use so the one I used was just a random one from a old PCBSo how could I do this?Thanks in advance!

author: oPossum
author_rank: Super Contributor
timestamp: April 30, 2020, 06:39:58 pm
content: An inverting op-amp mixer. It has some magical properties. The summing node is essentially at ground potential so what comes in one input does not go out the others. It also has consistent input impedance (determined by R1) no matter how many inputs are used. It can also have different gain on the various inputs if needed.

author: Daan32
author_rank: Newbie
timestamp: April 30, 2020, 06:49:16 pm
content: Ok so R1 should be resistors of equal value (10K Ohm?) And What value should R2 be? and also what kind of diode is that, and the Ground is connected together with the ground of all the inputs, right?

author: klr5205
author_rank: Regular Contributor
timestamp: April 30, 2020, 07:22:40 pm
content: The triangular symbol is an op amp.You get to choose the resistor values, but something around 100k for R2 would be a common choice.R1 is chosen to give the gain you want for a given input. They could all be the same - or not! You could put pots in the R1 positions to control the volume of each channel separately.The formula for an inverting summing amplifer is Vout = -R2((Sum of all inputs)/R1)) , assuming R1 is the same value for all inputs.Plenty of examples around if you do a search on op amp summing amplifier circuits. Or audio mixers. Potato potato.

author: Daan32
author_rank: Newbie
timestamp: April 30, 2020, 07:55:24 pm
content: yeah sorry I didn't really know what to search for, but thanks, this will do!

author: TimFox
author_rank: Super Contributor
timestamp: April 30, 2020, 08:13:12 pm
content: In this adder circuit, make sure that any gain control you use does not reduce the resistance from the summing point (virtual ground) to actual ground to a small value. For example, do not use a potentiometer connected directly to the summing point where the connection is grounded at one end of travel. This would cause the noise and dc output to increase out of control. For gain tweaking, a variable resistance can go in series with the input resistance or feedback resistance, or the wiper of a pot can drive the left end of a input resistor.
No beep voltcraft VC 870 - Page 1
Forum section: electronics / beginners

author: tomcourtney
author_rank: Newbie
timestamp: February 23, 2020, 02:49:46 am
content: Bought the vc 870 some years ago with a view I would learn how to use it. Looked for some online training YouTube etc but seem to have a problem.There is no beep on continuity or elsewhere and the laser temp unit is reading everything between 500 and 80 deg C. All else seems ok.User manual assumes you know what you are doing.... is there a setting to change? Is there a menu system and if so how do you scroll it? Could it be the 500ma fuseOr is it knackered?Sorry I'm a complete idiot where electrics is concerned but I need to learn the basics as I have a boat.

author: JFJ
author_rank: Regular Contributor
timestamp: February 23, 2020, 04:42:03 pm
content: After setting the meter's selector switch to Ω, does pressing the 'Select' button bring up the continuity bleeper symbolon the display?If so, but there's no sound when the probes are shorted together, does your meter produce any sounds in other modes? For example, there should be an audible alarm if a test lead is plugged into one the current measurement sockets (10A or mAµA) while the selector switch is set for a voltage measurement.
No Buzzer on Keysight U2741A - Page 1
Forum section: electronics / beginners

author: eddy2u
author_rank: Newbie
timestamp: January 27, 2023, 03:52:59 pm
content: I just bought a Keysight U2741A on ebay and apparently there is no way to get it to buzz in continuity mode.Was wondering if there was a way to program a trigger in lab Vu to make sound on my PC?
No clean flux is a lie - Page 1
Forum section: electronics / beginners

author: bobbydazzler
author_rank: Regular Contributor
timestamp: May 16, 2021, 05:09:00 pm
content: About 2 months after it was soldered up.

author: boB
author_rank: Frequent Contributor
timestamp: May 16, 2021, 05:16:29 pm
content: You sure that you "deactivated" it by heating it up everywhere ?I'm not sure exactly what part of the board you are thinking about ?What I have seen when active flux (clean or no-clean) is that when it has not been heated up everywhere, it can conduct.Some flux like rosin can leave a residue but doesn't necessarily have to be cleaned up.There was this stuff called "Flux Off" (I think ?) that worked pretty well but if active flux gets underneath a part, it can even corrode and conduct.I know that actual washing flux can be a real pain in the arse to set up and do correctly.Curious what your PCB is doing.

author: coppice
author_rank: Super Contributor
timestamp: May 16, 2021, 05:22:51 pm
content: When they claim that you don't have to clean off the flux, its rather like claiming you don't have to clean your home. While true, there may be negative consequences.Even if the no clean flux doesn't result in long term corrosion, you can find many high impedance designs where it fails due to surface leakage. This may be leakage through the flux itself, or by the flux promoting moisture buildup on the surface of the board. A clean board needs to be in close to 100% humidity for much moisture to settle on the surface, but a dirty or fluxy board can become moist at quite low humidity levels.As usual in engineering, one size does not fit all.

author: ataradov
author_rank: Super Contributor
timestamp: May 16, 2021, 05:32:48 pm
content: I see no damage. If you are talking about the mess sticking to the board, then this is not what is understood under "no clean",. It does not mean it will evaporate somehow. It means it will not corrode the board in 2 months.And yes, no clean only applies to the fully activated flux, which is highly unlikely while hand soldering. So clean any type of flux.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 16, 2021, 11:42:11 pm
content: "No Clean" means that the stuff is impossible to get off your PCB.If you want a clean PCB, then use flux that easily dissolves in water or IPA.
No current voltage divider - Page 1
Forum section: electronics / beginners

author: Steven Douglas
author_rank: Newbie
timestamp: March 08, 2015, 05:33:46 pm
content: So first off I'm using a 12 volt power supply, going to be a battery. I'm using a 555 timer to drive a oscillation circuit for a HV drive. I want to use a voltage divider to power a 6 volt transistor, off of the out pin on the 555. But also at the same time i do not want to have current flowing across the second resistor to ground, it just seems to be a waste of power. Does anyone have any idea how to overcome this, but still keep a good signal going to the transistor?I would like to just use the one transistor for the switching it is a TIP42c I have had it hooked up through a 1k resistor to the base from the out pin and it works fine but once i have made my device I want it to last as long as possible, so im trying to meet the ratings required rather than going overboard. I thought of using a voltage regulator but I also thought by using one it would cut out the signal and just give me a constant DC voltage.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 08, 2015, 06:19:42 pm
content: Strange story, i cannot make not much of it. You do not want to waste power in a resistor to ground, but use a TIP42C, that, per definition, has a lot of losses?Perhaps a schematic could help.

author: retrolefty
author_rank: Super Contributor
timestamp: March 08, 2015, 06:40:07 pm
content: Short of providing a schematic drawing, any feedback you get will be pretty speculative.

author: gdewitte
author_rank: Unknown
timestamp: March 08, 2015, 07:52:21 pm
content: +1 for a schematic. Per Ohm's Law, a resistor with zero current through it has no voltage across it. While you can minimize the current in a voltage divider by using high-value resistors, you need some current for it to work.

author: Anand
author_rank: Contributor
timestamp: March 08, 2015, 09:41:51 pm
content: I think you're looking for a 6V regulator (search for an adjustable regulator, with an ADJ pin), connected from the battery (Vin pin) to the MOSFET (Vout pin) and enabled (EN pin) from the output of the 555.
No external trigger on oscilloscope!!!! - Page 1
Forum section: electronics / beginners

author: ticktock3t
author_rank: Contributor
timestamp: December 15, 2012, 02:21:21 am
content: A while back I purchased an HP54602b oscilloscope(with gpib module) for $100. It was nice at the time when I was just playing around with electronics but lately i've been working on a radio circuit. I connected my rigol dg1022 function generator to channel 1 and tried to connect the function generators output sync to channel 4 on my oscilloscope. However, I soon realized that my oscilloscope didn't have a trigger option for external trigger. The best I can do is to set the oscilloscope to use channel 4 as the trigger but it doesn't help much. Is there anyway I can get around this problem and still use an external trigger on my oscilloscope?

author: w2aew
author_rank: Super Contributor
timestamp: December 15, 2012, 03:43:52 am
content: Quote from: ticktock3t on December 15, 2012, 02:21:21 amMany/most scopes don't have a separate input for external trigger when they have four input channels. In these cases, you simply use one of the four channels as the trigger if needed.Why do you say that this "doesn't help much"?

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 15, 2012, 04:25:08 am
content: 1M$ question... do you terminate your synch signal with 50ohm terminator?

author: aghp
author_rank: Regular Contributor
timestamp: December 15, 2012, 12:19:38 pm
content: Quote from: ticktock3t on December 15, 2012, 02:21:21 amYou can use all channels as "external trigger" but...This oscilloscope have not any advantage if there is separate "Ext trig" input(s) exept if you need all 4 main channels and then external trig. So manufacturer have not added "Ext trig" becouse it do not give nearly anything in this scope.Now need very tightly remember that this oscilloscope is "150 MHz" oscilloscopeonly in repetitive mode.In HP datasheet it is classified as 0-2MHz // 0-1MHz "one shot" oscilloscope.This oscilloscope is made basically for repetitive signals where also naturally of course trig is "repetitive" and maybe mostly every capture is derived from signal under test.If use short single pulse for trig... oscilloscope do single realtime sweep. If there is "Ext trig" what it change. Nearly just nothing... it is still 20MSa/s // 10MSa/s single shot. You can use what ever main channel as "ext trig" input.If you do something like external trig starts every capture... these captures are as "single shot" captures using 20MSa/s maximum and of course all channels can use for trig as ext trig.It havemaximum20MSa/s and this is only using fast horizontal speeds. This oscilloscope have 2k / 4k sampling buffer. (with 20MSa/s it is full in every 0.2ms.)What are you trying with this measurement... you tell:"........ but lately i've been working on a radio circuit".This rise this question.. what kind of measurement setup (and parameters) you try with this generator, sync/trig and working with radio circuit using this "1 or 2MHz real time" oscilloscope.Do you try break fundamentals?
No idea which high voltage power supply to choose. Veterans help! - Page 1
Forum section: electronics / beginners

author: phizics
author_rank: Newbie
timestamp: August 20, 2016, 08:50:50 pm
content: So, I've started working on a fusor (simple particle accelerator / fusion machine), and for it I need a high voltage DC power supply. High voltage would mean up from 20 kV. The current which I need, I assume, will dicate the price range in which I am buying heavily. I am looking for a PSU that can give 0-10E-6 A up to something that nets 0-10E-3 A.I have done a few hours worth of digging but I never know what to choose.Do you have any suggestions on what I should buy from personal experience? Or maybe some tips on what to look out for when picking? My price range is fairly low, and I do not know how realistic it is, but I'd like to go up to 300 euro (340 dollars, tax included). If my price isn't realistic, which one is?I may need to provide additional information on my project for you to figure out what I need. If that's the case, I did not provide that information because I did not realise it was important. Please do tell me about it, and I will supply you it.Thank you all for your help in advance.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: August 21, 2016, 02:59:19 am
content: I've been out of this area for a while now, but I still remember one thing: don't buy CAEN if you can avoid it. Their kit never works right.
No Need for a super high bandwidth, super high accuracy In Amp - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: May 20, 2020, 08:05:57 pm
content: Hi,We wish to compare two voltages and see which is highest, and get a rough measurement of the difference. We came up with the attached circuit.Its cheaper than an In Amp….eg we could just use an MCP6002 dual opamp. Though we aren’t sure. We can’t find In Amps with this ease of functionality. Do you know of one off hand?LTspice sim and pdf schem attached

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 20, 2020, 11:26:41 pm
content: It can work. Are you sure you need to amplify that voltage difference?But wouldn't it be easier to do a straight measure of both voltages? Switch ADC input from first to second voltage in order?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 20, 2020, 11:43:43 pm
content: What sort of accuracy do you need?The biggest inaccuracies are likely from the offset voltage of the opamp used.This can be greatly reduced if you can use for example a 30V power supply (which most opamps can handle) combined with a 2:1 voltage divider on the 48V and 52V power rails.Then after the opamp you can use a 30V to 5V ratio divider to bring the output in range of your ADC.Now you have a division ratio of approx 23 and then amplify the difference 8x, which also amplifies the opamp's offset 8x. If you can avoid the amplification, you also reduce amplification of the offset error.The classical differential amplifier with 4 resistors of equal size already gets you there, because the maximum voltage on the opamp inputs would then be half of the maximum of your power supply. I.E: 52V/2=26V, which is well within range of an opamp with a 30V power supply. You may want to add some protection for when the power supply of the opamp fails, filtering etc.Instead of using a passive divider on the output, you can also easily clamp the opamp output to within your ADC range. (Series resistor and (diodes to GND and +5V).
No power out from PCB - Page 1
Forum section: electronics / beginners

author: Ouagadougou
author_rank: Newbie
timestamp: January 12, 2022, 08:33:30 am
content: Hi there, first timer here. I’ve taken on a job of repairing a wine cooler, and have confirmed the PCB to be the problem. Power comes in, most components are getting power, but the final relay before the output to the compressor is not closing. With the relay not closing my first thought was it was faulty but I removed the relay and it tests fine on a 12V battery.Any other suggestions? Any parts on here that stand out as worth checking?Thanks!

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 12, 2022, 09:01:38 am
content: can you take a bottom picture? same picture quality as above.

author: Ouagadougou
author_rank: Newbie
timestamp: January 12, 2022, 09:26:20 am
content: Sorry about that, here ya go. The blank spots are where I removed a diode and relay for testing. Both tested fine, but I haven’t soldered them back in yet.

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 12, 2022, 07:43:04 pm
content: what i normally do is take two pictures. then in a image editing software. on a phone. overlay the copper side or switch from two picture.draw sketch of the circuit. i think there is a temperature knob somewhere. or a controller

author: rpiloverbd
author_rank: Regular Contributor
timestamp: January 13, 2022, 12:59:50 pm
content: So, it is confirmed that the relay is not getting power while in the board. Have you performed a continuity test of the PCB? Found any broken trace?
NO RESPONSE FROM GPS SCREEN - Page 1
Forum section: electronics / beginners

author: TOMSTROMS
author_rank: Newbie
timestamp: December 30, 2013, 11:05:10 pm
content: Hello eev people. My names Mike Im an electrician but dont know a lot about electronics.. Ive got this gps model mio c310. Im trying to be cheap and fix it up. Tha battery was crap so I got one on ebay. Looked at youtube to figure out how to replace and replaced it. Battery works fine now but the damn screen wont respond. Wondering if anyone knows what to do next other than buying a new gps. Ive spent money on the battery and would like to get this gps working. Its an old model so I assume parts are cheap. Any ideas? New any of the following.. Screen, main board, chip. Firmware problem? Ive tried a hard and soft reset to no avail. Also their is a strange look to the screen, like some sort of sepration inside, it works seems to boot up but it dosent look uniform, maybe that helps to know. Catch ya next time, just kidding.. Later

author: Rerouter
author_rank: Super Contributor
timestamp: December 30, 2013, 11:19:15 pm
content: plug it into your computer and make sure t has actually booted,Other than that, if all you have done is swap the battery, look for what else you could have bumped,

author: Psi
author_rank: Super Contributor
timestamp: December 30, 2013, 11:39:32 pm
content: Quote from: TOMSTROMS on December 30, 2013, 11:05:10 pmMaybe the touchscreen has separated from the LCD in some areas

author: Stonent
author_rank: Super Contributor
timestamp: December 30, 2013, 11:45:58 pm
content: Any chance of a video?

author: TOMSTROMS
author_rank: Newbie
timestamp: January 04, 2014, 07:21:44 pm
content: Ive since hooked this device up to my computer. Ive reinstalled the software from the oem cd and not much has changed. Their is simply no response from the lcd.. I have done some more snooping and have learned that on top of the screen is placed a screen digitizer that seemingly transfers touch data to be processed. I have checked connections and they seem to be fine. Also before i replaced the battery I did notice a screen glitch kind of like a loose conection inside when the device was complete before dissasembly, maybe a chip going bad, dont know. These things are going for under 25 bucks on ebay, but i still kinda wanna fix this one, maybe I should just salvage my new battery and get a different one on ebay. Thanks to all who previously responded to this post for trying to help.
No thermal pad for GBJ2510 mains bridge? - Page 1
Forum section: electronics / beginners

author: Faringdon
author_rank: Super Contributor
timestamp: July 19, 2022, 03:48:40 pm
content: Hi,We have an engineer who wants to put a thermal pad between the GBJ2510 and a heatsink in a 240VAC PSU mains bridgeGBJ2510https://www.farnell.com/datasheets/2705147.pdfThe datasheet says 2500Vrms isolation, so can you confirm , no thermal pad is needed.

author: Gyro
author_rank: Super Contributor
timestamp: July 19, 2022, 04:35:25 pm
content: Make sure you have enough lead clearance from the heatsink - the datasheet shows (P) minimum 2.5mm. You may need insulation for that (you haven't specified product type, Class I / Class II etc.

author: langwadt
author_rank: Super Contributor
timestamp: July 19, 2022, 07:11:06 pm
content: you have an engineer working for you in the closet you had to rent because soldering wasn't allowed in your rented room?

author: JustMeHere
author_rank: Frequent Contributor
timestamp: July 19, 2022, 09:25:11 pm
content: You may not need the thermal pad for electrical isolation, but it's a good idea to use that or paste to attach the heatsink. This is because you will get better thermal conductivity because there is better contact.
NO to NC conversion - need help - Page 1
Forum section: electronics / beginners

author: ScotY
author_rank: Newbie
timestamp: November 14, 2018, 05:27:40 pm
content: Hello guys,I'm new here and, while I have a fascination with electronics, I do struggle a LOT.I have a wireless CNC tool height setter gizmo and would like to repurpose it. As it came, it has a battery operated plunger sensor/switch/transmitter that is NO. When a tool comes down and contacts the sensor pad, it closes the switch and sends a signal to the receiver unit. The receiver unit is NO and closes when a signal is received. I want to use the transmitter with a NC touchprobe. My CNC controller wants a NC signal. So, both the transmitter and receiver need some sort of circuitry to convert the NO to NC. Can someone help me figure out how to do this? The TX circuitry must be as compact as possible, the RX circuitry doesn't matter so much.Thanks in advance and I hope I have provided enough information to explain.Scot

author: helius
author_rank: Super Contributor
timestamp: November 14, 2018, 05:41:53 pm
content: You can't really "convert NO to NC" as there is no information about electrical potential. The circuit connected to the switch may be AC to drive a relay, or 5VDC to power a TTL device, or something else. If everything is just run from 5V, it can be as simple as a single PNP transistor as a voltage inverter.

author: FriedMule
author_rank: Frequent Contributor
timestamp: November 14, 2018, 06:02:03 pm
content: First listen to helius and all other, before listening to me, I am properly less knowledgeable then you but my suggestion would be to use a relay that are NC so that when your circuit sends a NC the extra relay goes NO and opposite. (Warning may not work!!)

author: ScotY
author_rank: Newbie
timestamp: November 14, 2018, 06:31:21 pm
content: I had found this thread which gave me the idea:https://www.eevblog.com/forum/beginners/converting-a-normally-open-pushbutton-to-normally-closed/I didn’t mention earlier but the transmitter runs off 2 AA batteries. The receiver can run off 5-24vdc but I will probably use 5v. While the above mentioned thread sounds like it might work for me, I am not sure and the voltages used in his example are different from mine.
No undervolt option in Intel Extreme Tuning Utility for Dell inspiron 3583 - Page 1
Forum section: electronics / beginners

author: robsims
author_rank: Frequent Contributor
timestamp: June 17, 2020, 02:08:39 pm
content: Hi, I have some questionsI have a Dell Inspiron 3583 with Intel Core i3-8145U CPU @2.10 GHZ 2.30GHZ, running Windows 10.I want to undervolt my CPU and therefore i installed Intel Extreme Tuning Utility. In IXTU the option to undervolt is disabled(no possibility to undervolt) so i can not undervolt my CPU. Do i have to enable something, to have the possibility to undervolt my CPU, or is it that Intel doesn't allow these CPU's to be undervolted.Throttlestop also doesn't work on my laptop. Is there another free program so i can undervolt my CPU

author: robsims
author_rank: Frequent Contributor
timestamp: June 17, 2020, 03:06:58 pm
content: I posted my questions on the general computing page

author: magic
author_rank: Super Contributor
timestamp: June 17, 2020, 07:55:24 pm
content: Don't do that, it's a mess if people start responding randomly in two different threads.

author: robsims
author_rank: Frequent Contributor
timestamp: June 18, 2020, 02:48:02 am
content: I know, i tried, but i can not delete this post
NOAA humidity calculator question - Page 1
Forum section: electronics / beginners

author: 3roomlab
author_rank: Frequent Contributor
timestamp: July 06, 2019, 08:48:31 pm
content: so I was doing sanity check about humidity and temperatureusing this sitehttps://www.ready.noaa.gov/READYmoistcal.phpin the lower part of the displayabs humidity is what it is, grams of water in 1m3 of airbut what is "mixing ration" value g/kg ?

author: Nerull
author_rank: Frequent Contributor
timestamp: July 06, 2019, 08:51:46 pm
content: Its a typo for mixing ratio, though chemistry would call it mass ratio.It's the mass of water per kg of air.
Nodal Analysis with Voltage Sources - Page 1
Forum section: electronics / beginners

author: JOJOElectro29
author_rank: Contributor
timestamp: May 07, 2025, 11:17:09 am
content: Hi, I'm stuck here. I'm confused with how to apply nodal analysis here.

author: ledtester
author_rank: Super Contributor
timestamp: May 07, 2025, 01:44:56 pm
content: It would help to know exactly where you are stuck.Can you write down the nodal equations if the circuit if the "2v" and "4i" sources weren't in the circuit, i.e. replaced with wires?

author: JOJOElectro29
author_rank: Contributor
timestamp: May 07, 2025, 02:16:10 pm
content: I used two supernodes but it doesn't seem to be working. as you can see my v is wrong.

author: ledtester
author_rank: Super Contributor
timestamp: May 07, 2025, 02:57:56 pm
content: The "2v" source is a dependent current source. It means the current between C and GND is 2*v where v is the voltage across the 2S resistor.Similarly, the "4i" source is a dependent voltage source so the voltage between nodes C and D is 4*i where i is the current through the 1S resistor.So it seems the "2v" current source needs to be included in the KCL equation for supernodes 1 and 2.I'm not versed in the supernode method so I would just assign variables for all of the voltages and currents. Then for each node KCL says the sum of all the currents going into a node sum to zero and for each loop KVL says the voltage around the loop is zero. Then solve the resulting set of equations.Have you learned about superposition?

author: JOJOElectro29
author_rank: Contributor
timestamp: May 08, 2025, 04:38:28 am
content: I got my answer closer this time, any errors? Would like to get the exact number if possible. Yes I have learnt superposition, but for this Example I'm supposed to use supernode to solve it.

author: iMo
author_rank: Super Contributor
timestamp: May 08, 2025, 06:36:39 am
content: A hint: always draw nice visible "dots" where the two or more wires join in your schematics..

author: ledtester
author_rank: Super Contributor
timestamp: May 08, 2025, 03:43:47 pm
content: All of the values are multiples of 1/9. Your discriminate is 21 so maybe you made an arithmetic error there?Here is what I came up with... the variables are i, v, i_ab, i_bc, v_dKCL at supernode 1V: i - i_ab + 2*v_d - 2 - 2*v = 0KCL at supernode 4i: -i -2*v_d + 2*v + i_bc = 0KCL at B: i_ab + 2 - i_bc = 0KVL around the outside: v - i_bc - 4*i - i = 0KVL around A, GND and D: v_d - i + 1 = 0Relationship between v and i_ab: v + i_ab/2 = 0These are six equations and you only need 5 of them -- you can get rid of KCL at B, for instance.Going over tohttps://live.sympy.organd entering the equations:Code:i, iab, ibc, vd, v = symbols("i iab ibc vd v")eq1 = i - iab + 2*vd - 2 - 2*veq2 = -i - 2*vd + 2*v + ibceq3 = iab + 2 - ibceq4 = v - ibc - 4*i - ieq5 = vd - i + 1eq6 = v + iab/2solve([eq1, eq2, eq3, eq4, eq5, eq6], [i, v, iab, ibc, vd])yields:Code:{i: 4/3, iab: -52/9, ibc: -34/9, v: 26/9, vd: 1/3}
Nodal Analysis - Page 1
Forum section: electronics / beginners

author: Oldman79
author_rank: Contributor
timestamp: February 28, 2020, 04:11:04 am
content: Hi GuysI am trying to practice some nodal analysis but my math is not agreeing with the LTSpice I am using to check my work.Attached is my workings if anyone can see what I am getting wrong it would be appreciated.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: February 28, 2020, 05:36:56 am
content: The errors are with the "Node c KCL" and "Node d KCL" equations.Look at the calculations for currents through R2 and R6. Can you see the problem?

author: Oldman79
author_rank: Contributor
timestamp: February 28, 2020, 07:49:03 am
content: Ahh I see, thank you
Node analysis /Mesh analysis questions ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 25, 2019, 03:39:52 am
content: What's the next level up from NA/MA for DC analysis where you could say, if you have so many nodes, loops, resistors, diodes and BJTs...you could fill in all the values and get currents/voltages ?If you have a big 10 or 20 BJT circuit, does anyone sit down any write out however many N/M equations there would be? I have a 8 BJT PSU, and I don't know where to start, it's a tangle just to unravel the paths.Or is there a much quicker way you learn later, and in an exam you can quickly solve 10 or 20 BJT circuits ?

author: fourierpwn
author_rank: Regular Contributor
timestamp: July 25, 2019, 04:26:29 am
content: Quote from: lordvader88 on July 25, 2019, 03:39:52 amYa, it's called simulationsAs far as "what's the next level up...". There isn't really anything in terms of manual analysis. This is why we turn to EDA software where quickly slapping together the circuit and running some simulations is far superior than anything pen and paper can return.The PSU problem you speak of, is this a hobby project or do you have a teacher who is a sadist and is making you run through hoops just to ensure that you understand the theory?

author: lordvader88
author_rank: Frequent Contributor
timestamp: July 25, 2019, 05:06:24 am
content: No I just gave it a try on a PSU I made. I bet whoever designed it never had an electronic calculator either, let alone a matrix solver.Ok, as builders, there's nothing wrong with cheating and measuring a few voltages and currents to cut down on the number of eqn's.
Node voltage and actual current path when output is grounded ? - Page 1
Forum section: electronics / beginners

author: MathWizard
author_rank: Super Contributor
timestamp: May 04, 2023, 12:15:12 pm
content: When I've been finding things like Y or T parameters, I've been doing node analysis on the shorted output node, and getting the right answer until yesterday (at least for simple cases). And I see it done by prof's in pdf's too, like on page 3.https://d13mk4zmvuctmz.cloudfront.net/assets/main/study-material/notes/electrical-engineering_engineering_network-analysis_two-port-network_notes.pdfNormally you would setup up at least 1 less equation than total node #, and not setup the equation for the reference node. When I setup the shorted output node eqn, I don't include everything else that actually enters/leaves the reference node.So if you make a circuit like below, similar to a small signal model BJT with a feedback path between base-collector, and short the output, I would say the current from R2 still enters physical node c, and the correct amount goes into B1, and the rest takes the output V2 path. And if I replace the perfect wire with any amount of small resistance, you get a slightly smaller output current.So in this pdf below about BJT's and their capacitance, calling i_out the actual current that goes to the collector pin.....won't their simplified circuit give the wrong i_out ? The actual, dependent current source current, will still be the same. But how can say the current through Cu, would not enter the collector region, and then partly out the collector to AC ground ??see page 14 or pic belowhttps://pages.hmc.edu/mspencer/e151/sp21/notes/16.pdf

author: MathWizard
author_rank: Super Contributor
timestamp: May 07, 2023, 10:25:01 pm
content: I've gone through a bunch of 2-port problems with dependent sources, in a pdf for review, and got them all right.So for the BJT , in the top of their equation, how can they not be missing a -sCu term ??i_out= i_b[(gm-sCu)/(gpi+s(Cpi+Cu))]

author: MathWizard
author_rank: Super Contributor
timestamp: May 09, 2023, 09:47:59 pm
content: So I am right, it's just they ignore it for the frequency and typical gm the model is meant to work at.
NodeMCU 0.9 vs 1.0 targets w/Arduino - major differences in compiled code? - Page 1
Forum section: electronics / beginners

author: mortrek
author_rank: Contributor
timestamp: October 14, 2020, 05:35:36 pm
content: I have a fairly simple Arduino IDE project where I accidentally compiled for NodeMCU 0.9 (ESP-12) and it was actually a NodeMCU 1.0 (ESP-12E). The 0.9 version worked, but was occasionally unstable and would throw an exception/lock up a few times a day. Since changing it to NodeMCU 1.0, it has worked flawlessly.I'm curious as to why? All the info I've found says that the 12 and the 12E are almost identical except for a few extra IOs. Based on my results, there has to be more to it than that, right? Maybe a difference between NodeMCU versions, unrelated to the ESP8266 module itself?I'm using the ESP8266 Arduino library 2.7.4 with Arduino 1.8.12. I'm not doing anything fancy with it, mainly just connecting to wifi, serving webpages, and controlling some digital output pins.edit: I cannot seem to find the original ESP-12 datasheet, so I can't even make comparisons between the two that way...Also boards.txt is almost identical between the two. Running diff shows the only significant difference is that the 0.9 uses qio, 1.0 uses dio for flash mode.

author: bizkits
author_rank: Contributor
timestamp: October 14, 2020, 06:12:58 pm
content: Could it be in the newer version, they fixed some memory issues or optimized some of the codes?