How to Measure Capacitance without Desoldering Capacitors from a PCB
Our today's video is about capacitance measurements. Not just regular capacitance measurements but measurements without desoldering capacitors from a PCB.
During the past several years different internet marketplaces are offering various devices that can measure capacitance and other parameters of capacitors without desoldering them from a PCB.
There are many discussions on different forums, some people buy them, some people don't, some share experiences. Personally, I am interested in two questions. First of all, the manufacturer lists never include well-known brands like FLUKE, APPA, UNI-T, MASTECH, etc., are never present in manufacturer lists. So, none of the trusted brands produce such devices. And the second question is strictly technical, it's based on elementary knowledge of school physics. At school we were taught that if two capacitors are connected in parallel, their equivalent capacitance will be equal to the sum of their individual capacitance. If in series, then we have a more complicated formula. We have to deal with inverted values, so 1/C = 1/C1 + 1/C2.
Here we have a PCB and we want to measure capacitance of this capacitor. Its contacts are right here. When we connect a multimeter, or another device that measures capacitance, to those contacts, we will obtain a value of the actual capacitance only if one single element, this capacitor, is soldered between those two points. There is not one element on the PCB, there are more than a hundred. Therefore, capacitance between those two points will be equal to some equivalent value, which is not that easy to calculate. This is why, even theoretically, based on the knowledge of school physics, it's not possible to measure capacitance of an element without desoldering it from a PCB. But enough of theory, let's move on to practice.
We will conduct a number of measurements on this PCB. As you can see, it has many different components: electrolytic capacitors, SMD capacitors, inductors, resistors, microchips, light-emitting diodes - a whole package. We will conduct measurements in several steps. I have already completed the first step - I have written down all of the nominal capacitance values in the points where measurements will be taken. There's one exception: there is no capacitor in point 5, as it has been previously removed. Out of curiosity, we will measure capacitance in this point as well. In the second step I will measure capacitance in those points without desoldering the capacitors. In the third step I will desolder all capacitors, measure their capacitance in a normal way and record the values. We will compare them and find a result.
In this video I have shown you that measuring capacitance without desoldering capacitors from a PCB is a myth.
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I came here to learn how to measure caps without desoldering…..still waiting
With an 100khz esr meter outputting less than 0.5v(to not switch on surrounding active components), you can test the esr. For 10uf and higher, even with a 2ohm resistor across the cap; if the reading is higher than 1ohm, the cap is suspect.
I'm a total novice, just developing an interest in electronics, I was wondering why my results measuring capacitors in a PCB were so weird, and this video taught me why. thank you very much.
I have done repairs for 40 years + do you know how many people have told me I do not have to remove the part to measure its value? More then I can count. I will just send them right to this video in future. Great video! Just great.
Thank you! We are glad that we helped you!
@@ToolBoomVideo Your assertion that no other method works for testing capacitors may very well be accurate, however, your omission of any other method in your demonstration does not help in proving that assertion. It actually was a waste of my time.
Great video thanks. I'm getting back into the electronics hobby and found this helpful.
I'm just getting started learning about circuits and tests. I appreciate your advice and proof, You saved me $60.
Excellent tutorial. That's what I suspected all along but now you've proven it. Great job.
At the start I thought you had discovered a multimeter to accurately measure capacitance in circuit. This went against all that I know so I am pleased that your tests prove my assumption right. A very good test.
The title was missleading
Yes, false advertisement
Very well done the measurement of the capacitor. I think I will buy such a measurement device. Thank you for your nice adversment
thanks so much mr boom just bought a new meter like yours had no idea what to do im going try it now with your help brill thanks we all need to work together with help xxxx
Thanks for the information!
This video makes me feel uneasy. Liked!
Thanks, I watched several before yours and yours was the most understandable.
Thank you, we are very glad that you liked it
Thank you sooooooo much for this video fantastic explanation to the point. Question how would you measure ceramic SMD caps on the PCB and a fluxe 87V RMS multimeter will it do the job. if you can make a video of the ceramic SMD capacitors test many thanks in advance.
Keysignt U1733C Handheld LCR Meter also measures ESR, so yes, these meters are made by well-known instrument companies. Keysight is comparable to Tektronix, Fluke, etc. any day.
I have seen people clip on to a capacitor on board claiming to be an accurate test. I am learning about this stuff little by little and my knowledge base on available equipment is extremely limited so please bare with me here. Would a tester with a specific clip type work for on board reading IF the clips caused a temporary circuit interruption? Thus effectively removing the capacitor from the board while it is still attached.
Hi! Okay can I ask how do you measure a capacitor in circuit on a non pcb board ? I have just built a speaker system where one speaker is fine the other the tweeter and mid range has no sound. The crossover is dedicated to the tweeter and mid, the woofer has its own. I have checked all, the drivers with a multimeter, they are fine, drivers hooked up directly to wiring of the binding posts, all good. Once hooked up to the crossover, nothing. The crossover is identical to the one in the speaker that works, have checked, have checked, it looks fine, everything fares out. I am left with is there something wrong with the crossover ? Hence I want to check the caps ( high end caps ) they are of course soldered in place and glued to the ply board. How can I measure each cap to see if one is dead ( long shot as they are new ) Another question if there is a dead cap in place would that stop the current flow, hence no sound or would it go through and mess with the sound ? Sorry for the long story, I am fed up trying to sort it out, I need help... thanks Alain
If you suspect that you have a defective power supplies and you only have a few capacitors....then just "recap" the unit. If the unit works...then problem solved...if it still does not work then double check your work to make sure you've replaced the caps properly ( verify value and polarity. If everything is OK then go on to further diagnosis!
Do you have the circuit diagram of the front end of that UNi-T capacitance section of that meter. I have one and it measures about half capacitance and inductance for everything. Haven't figured out the fault yet. I seems to have a 7555 driving oscillations which is OK but think the fault is elsewhere.
Cool video shot, thanks for sharing it with us, well done :)
Well, let me say that I was on the hunt for an in circuit ESR Capacitance tester. Not any more. I thought maybe the technology had improved in some way. Interestingly, B&K sells one of these. A company that was usually well respected. Its obvious that the best way to find a suspected problem capacitor is to understand the operation of the circuit it is installed in. Then, once you narrow down the basic area, you can surmise which component may be causing the problem. It would seem that good analytical and technical troubleshooting skills are still a must.
ESR can tell you if a capacitor is out of spec. It won't give you accuracy, but will help you troubleshoot.
the capacitor when it is bad is bulged.when shorted not bulged.esr is accrurate enough
ESR meter is an invaluable tool. Doesn’t have to be perfectly accurate. It’s well accurate enough.
@@cotto887 lol, not always. Not that often.
@@kilgoretrout4461 Did you try it out. Does it work in circuit to hunt down bad caps? If it works I'll buy one.
It is better to use an ESR meter? Does a fluke 115 work in a similar way or it is better?
To tell people not to buy an ESR meter is plain bad advice. When a capacitor goes bad it is WAY out of spec (you don't need super accurate measurements)and most often the reason why a circuit failed. For quick troubleshooting an ESR meter is priceless.
Most of the times electrolytic caps looses about 20-30% of capacitance with increased ESR, and for most applications even cheap chinese transistor-tester tool is enough.
Exactly right, an ESR meter is essential to troubleshooting. And you cant measure capacitance in circuit. Yoyr measuring more than just the capacitor. Often these caps are in parallel so, your measuring two caps etc..
@@clems6989 So what's the alternative? Alot of PCBs have hundreds of caps. You can't exactly de-solder each one as there's too many and you make a mess of it. So how can you check for bad caps in circuit? Not really concerned with the measurement but just which one is dead or malfunctioning. You can have a good reading but the cap could be dead. So any alternatives?
@@jonfreeman9682 Thats where an ESR meter comes in. It can measure in circuit. And if the Electrolytic cap goes bad, the esr will increase (a lot.)
@@clems6989 Okay I'll order one to give it a shot. I'm trying to fix a TV and there's hundreds maybe thousands of caps and it's not practical to de-solder each one. An in circuit tester would be helpful. Don't care about measuring capacitance but just wanna know which one is dead and needs replacement. Thanks.
Thank you sir..I was about to buy ESR but now I changed my mind.
Hello! We are glad that our video helped you! Subscribe to our channel, there will be many interesting videos and reviews!
It is possible do measure capacitors on the PCB. You just have to cut the traces near the capacitor or desolder and remove every other components from the board. Notice that for the second capacitor, you don't have to put all components back, just remove the first and put the second in its place. However, I don't know if it works for flux capacitors.
Hello! Thanks for the great and detailed comment!
I got an ESR capacitor analyser
Just finishing an hnc in electrical engineering and been told to always remove from board to test capacitor. one quick question on capacitor 6 where there was a 35% variation in the reading would you consider that capacitor as faulty. what would you say is an acceptable tolerance? thanks for the video.
Hello! In this video, we wanted to demonstrate how the multimeter readings differ when measuring the capacitor's capacitance on board, and when measuring the same capacitor, soldered from the board. Measurements showed that the capacity of one of the capacitors was significantly different from the nominal. Obviously, it was damaged. Since the video was made a few years ago, we no longer have those board and capacitors, as well as technical documentation. Therefore, we can’t re-examine or verify it.
the tolerance for electroletic cap is 20 percent that cap is faulty
Thank you! What a great video!
We can't measure capacitance inside circuit but we can measure ESR in circuit with MESR-100 which is good enough to troubleshoot any circuit dead because of a capacitor
but with a mesr100 you get an accurate measurement that tells you that the capacitor is bad.
@@cotto887 What do you mean "but" you are almost saying what he said. is that a question without a question mark? You might be able to find bad caps with the mesr100 but it is still best to take them out of circuit to double check. A capacitor needs to be checked with the correct frequency depending on it's value. the mesr100 uses 100khz which is good enough to give you a rough idea for most caps. but if there are more than one capacitor in parallel you need to take that into consideration. Try borrowing one and checking esr values when you put different voltage and different values in parallel. If the circuit needs to see an esr of a certain value them you may want to experiment with capacitor combinations to get a really good value. Some of the cheaper caps from asia might not have the esr you are expecting to see but sometimes you might be able to improve the esr value by mixing 2 new caps in parallel to make up the replacement part..
That's all I wanna know. Is the cap bad or not. So this tool works to find bad caps?
@@jonfreeman9682 Yes exactly
@@irfanmkws Okay thanks. I'm gunna order one to test it out. It's just not practical to de-solder hundreds of caps to test each one.
i think that you should test with ESR and then see? why didn’t you test it with ESR ? thank you for your time and effort 👍
If you wish to test a capacitor without removing from the PCB maybe it would be better to test with a device intended to test a capacitor in place. I don't think this multimeter is intended to test in place.
So what device would that be?
ESR meter?
Can the method be used to measure whether or not a capacitor is connected to the circuit on both leads, ignoring what its actual value is?
It is *not* the capacitance which usually degrades. It is the Equivalent Series Resistance.
Yes
OK! I like the video and everything is 85% correct except when you mentioned the word ESR along with capacitance measurements. Oh, and the part of big name companies. 1st ESR (Equivalent Series Resistance) I don't see the word capacitance in ESR anywhere? ESR measures Equivalent (Series) Resistance and can measure this (in a circuit)However there are situations when it can't, This is all fact even without going to Tech (school) as you put it. 2nd: big names. Agilent/Keysight, BK Precision, Instek These are all big names some bigger than other and some are about as big as it gets, I'm leaving many out. However, some of the big brands are adding the functionality to their LCR meters Making them LCR/ESR meters. Again your pretty spot on, when it comes to capacitance in a circuit. Now let us go back to that same school you were talking about. I'm sure you will remember something about capacitance values along with what happens when the value of a capacitor starts to drop, No matter why, time, voltage or damage. Remember what happens? As capacitance value drops (resistance value increases) WHAAAT? So, you mean to tell me somehow if you could measure the resistance of a CAP (in a circuit) he'll I don't know maybe with something low like 100Khz or less, that you could tell if a CAP was good or bad. Just by, if the resistance was within spec? And not even check the capacitance? Well, yes I believe that is what I'm saying, "it's called an ESR meter". They have been around for a long time now. I know this post is older, sometimes I can't help myself! While reading remember I am (not) claiming his entire video is wrong just a little one sided is all! Thanks for reading. Hope you enjoyed whether you agree or not, sorry for any spelling errors am in a hurry!
I've purchased UT-139B the other day and I like it a lot. Where can I buy compatible mini aligator clip probes, like these in the video but with a bit longer cable?
www.banggood.com/SMD-Inductor-Test-Meter-Clip-Probe-for-Resistor-Capacitor-Multimeter-p-912618.html www.banggood.com/6Pcs-Multimeter-Lead-Wire-Kit-SMD-IC-Hook-Test-Clip-Probes-Cable-p-930562.html
amazon
Is it possible to lift just one leg of the capacitor out of circuit then test? Or would that also give you false readings?
ESR meters use a 100 KHz sine wave, as to not activate other components when tested "in circuit". And is still a valuable tool for testing them. However a capacitance tester is also a good tool also. But does not measure "leakage", which requires another tester, especially for electrolytic capacitors. So, it's not easy to determine if a capacitor is actually good or bad.
You are right, therefore, certain rules for measuring components must be followed.
Geeze.. I'm still @@ mind boggled, I'm clearly outta my league. Thanks for the video
Hello! We're glad you liked our videos. Stay tuned!
To test Caps in Circuit I use Diode Mode. If any electrolytic stay shorted then I’ll remove it and test it. Usually easy to find the fault. However I am learning myself.
Can you explain how this works.
@@jonfreeman9682 if the cap your testing takes charge, swap the leads and do it again. When you swap the leads the cap will discharge showing a short for a spit second and recharge. Swap them again the same thing will happen. Like my comment said I’m no expert but this got me for a while.
@@jj74qformerlyjailbreak3 That sounds like it might work. So I use the diode test to charge it up then switch the leads to see if it sparks to short it out. This proves the cap is holding its charge. A bad cap would not hold its charge so it doesn't spark. Ok I'll give it a try. Thanks for the tip.
@@jj74qformerlyjailbreak3 That's really all I'm after to find the bad cap. There may be under performing caps that still hold a charge but may not be up to spec but I think most caps either work or don't and the circuit should be designed well enough that there's tolerance for caps a little out of spec. So the goal is to find the really bad caps that don't work at all.
@@jonfreeman9682 sometimes it’s best to replace all electrolytic caps. Even this method only takes you so far.
Oh!!! Very good idea. Very Tnx!!
I’m working on a synthesizer that doesn’t work. This thing has easily more than a hundred electrolytic capacitors, which don’t look damaged or swollen - are you suggesting that I remove every single one from the PCB, when I could use an ESR meter and get “maybe not the most accurate” measurements, which will get me a rough idea of which capacitor, is causing the problem?
I'm not saying you should remove all of them, but yeah, good ESR should be a go-no-go test to replace or not replace a cap w/o having to spend a load of time removing/installing caps.
Good vedio Sir thank u
I find it hard to believe that those caps are off that far I use a deck top multi meter tha has a capacitance test in it and have never had a different reading in or out of curcit. A good meter will induce a very low current for testing and will not upset other things in the curcit as other meters will
Just an observation why are you not measuring the capacitors with its correct polarity meaning black wire to negative and red wire to positive? Does the Uni-T UT139C measure electrolytic capacitors that way?
In this case the polarity does not affect the measurement result.
This is a great video that helps me save a lot of time that I would have wasted testing in circuit. Thanks. This video verified what I thought
Thank you! We are happy to be of service to you!
With an 100khz esr meter outputting less than 0.5v(to not switch on surrounding active components), you can test the esr. For electrolytics, 10uf and higher, even with a 2ohm resistor across the cap; if the reading is higher than 1ohm, the cap is suspect.
Excellent
I'm not so much interested in checking capacitance, is it possible to just check if a capacitor is OK? I currently have a project with over 100 caps that I need to check/replace and it would save a lot of time.
That's what I'm trying to figure out. There are hundreds if not thousands of caps. How can you test without de-solder everything?
Thanks dude, but I think you should discharge caps before measuring them by shorting their legs with any metal object like a jumper cable for a coupla seconds.
Actually if you noticed the board was not powered or energized for quite some time, in that case there would not be the Beed to discharge the capacitor.
What about if you're checking for shorts? It's possible to check in circuit accuratly enough?
Measurements using this method are quite accurate.
If you get a very low capacitance reading in circuit like you did with #6 then you know the capacitor is bad because the rest of the circuit can only add capacitance not subtract it.
Rod Bhar Capacitances diminish in series.
@@gordthor5351 At the cap's terminals, the reading will AT LEAST be the value of the capacitor. Anything connected to the terminals be in parallel, if it has a return path to the other terminal. You CAN read a lower value, if you're using an old-style bridge type tester.
I first thought it was a video showing how to measure capacitance without desoldering caps...
Victor Lee hi
That's what I thought. What a jerk.
He wasted my time
I was thinking, his poor wife has to listen to him talk like that 24/7. "As you can see, I'm firmly planted in my chair with my soda pop, consistently chilled to 7 ice cubes. And the value of its contents is 6.8 ounces. I now have an adjustment as I just took a sip"
An esr meter sends a wave, normally 100 kHz through from measuring point to meas. point., how accurate it is I don t know, cause I haven t received my DE 5000 yet, thank you.
The best instrument for testing capacitors is a curve tracer !!
Hi, plz suggest me which Meters is good and best to use True RMS , Fluke is very very expensive, I need next player in market .
We suggest that you pick up a True RMS multimeter from UNI-T, which offers reasonably good performance while being considerably cheaper than FLUKE products. You can find and compare UNI-T True RMS multimeters in our store: toolboom.com/en/catalogue/test-and-measuring-equipment/multimeters/?brand=uni-t&properties=3300
My LCR meter does a great job of measuring capacitors in-circuit. However, I primarily use it for non SMD components as for I don't work with them. But I get the same result with the meter when I measure capacitors in or out of circuit. So, they do work. And for the record, ALL the major brands make an LCR meter. A standard multimeter will NOT work.
@@Leilektsoglou It was so cheap, I really had nothing to lose. To my suprise, it measured caps in-circuit and measured down to 2pF!
@@Leilektsoglou I'm positive. If it says 18 on the cap, it measures 18 pF or so. If it says 22 on the cap, it measures 22 pF or so. It somehow even takes the capacitance of the probes out of the equation. I don't have a link to show it to you, you'll just have to trust me on that. For a $20 LCR meter, I was shocked and overly pleased. It also does inductors over 20 H which is large. I mean, don't expect a meter that cost over $100 but for what it does and the results I get, it's been worth every penny in my opinion.
@@LeilektsoglouAnd believe me, nowhere in the specs does it say you can test capacitors in-circuit or test them down to 2pF, it just does. I would buy it just for those 2 things alone if that's all it did. And I would pay a LOT more for it. It sounds too good to be true but, I'm not lying.
@@nonsuch Does it measure ESR aswell? And you mean theseone from Ali??
multimeter just applies 12v under room temperature to read value but real life a power capacitor turns out different in circuit under high volt current, temperature like imduction stove....aging deformation is best guess to replace capacitor
Omg I expected trick that let us measure it... To determine if capacitor is damaged, w/o desoldering, we can measure ESR with appropiate device.
@Mason Troy Whoa! It took me 1 second to realise you two are fucking scammers!
So after 6 years have you found a way to do it yet? Please share.
Hola ToolBoom saludos desde Costa Rica....por favor has el video en Español,un fuerte abrazo y nuevamente saludos.
The uni-t 139c is not very accurate for measuring capacitence nor is any other DMM in my experience. Perhaps in the ranges 1-1000 micro farad it's okay. But below or above that range, a DMM becomes slow and/or inaccurate. I measured only yesterday a 4700 uf capacitor with the uni-t 139c. It gave a reading of 4300 uf compared to a honeytek A6013L meter which gave 4680 uf reading. Which on do you think is correct? As for measuring a capacitor in circuit it is hardly worth debating. Of course you can't measure a capacitor in circuit with a DMM. The circuit affects the reading. However, with an oscilloscope and function generator and a bit of math you can! But it's probably easier just desoldering the part and measuring it.
Note the video is about explaining the method, the idea. It's not about this particular multimeter/brand/accuracy problems, guy said this one works ok for him, if someone has better one, needs better accuracy, what stops they to just use it. Even if Unit is not best one for building space rockets, it's clearly quite enough to detect a capacitor which is clearly broken, in everyday simple hobby projects, maybe old hifi, or guitar drive pedal, you don't have to own a Fluke nor some specialized capacitor test tools for that
@@wolo I don't think you understood my reply. I'm saying that almost all digital multimeters are bad at measuring capacitors. Especially relative to how great they generally are at measuring voltage and resistance. Can't speak for fluke because I don't own one but for accurate measurements of capacitors you would need an LCR meter or a meter dedicated specifically to capacitors. In addition to that an ESR meter is needed as well. Just because a capacitor measures to spec in capacitance doesn't mean it can't be failing in ESR. Edit.. Just rewatched the video. At the end of the video where he says to trust the DMM over an LCR Meter or an ESR meter is just false. You can't measure ESR in circuit the same as with capacitance so you have to remove the part from circuit to measure it. For the record I own a 8 different DMM's All of them are not accurate for capacitance except my siglent SDM3055 which is an expensive bench meter.
@@danishdart What I meant in short - that such capacitor specialized testers are owned mainly by advanced and professionals, and such knows these tricks already, but normal everyday enthusiasts with some of knowledge and some of tools usually don't own them. I can count 20 or 30 of my people, who has various class multimeters, at least minimum soldering skills, and was able to bring at least one broken device of any kind back to life, as far I know them. And I'm pretty sure, maybe 2 or 3 of them I can suspect possesion of such device like specialized capacitor esr meter etc. It's just not very common tool on hobby level. I personally, use the known aliexpress diy transistor tester tool/toy kit, but it won't be surprise to me if that thing measures them even worse, but tbh never compared results of mine to anything
Good luck sir 🎉
i noticed you never discharged any capacitor before you tested it on the PCB. just saying.
He may have done it during the cutaway at 6:12. Although he never mentioned anything about it, so it's impossible to tell.
because you did not descharge the caps . thats why the readings where not accurate
Just a guess, but I am guessing you do not own an ESR. Would have been a better video had you checked all of them including where one did not exist with an ESR. Especially the last one which appears, based on Capacitance reading out of circuit, to be a bad cap. Show the same in circuit test with ESR and out of circuit test with ESR, then conclude. I do not currently own an ESR and I am for sure a nooby. Was that circuit board bad, not working? Perhaps only not working because you removed a cap? Did you replace that last cap and the missing cap and put it back in service?
one of my capacitors measures OL on pcb, but when i desolder it and measure it, it is ok.. around 100uF ... i am trying to find out what is wrong with a monitor that won't turn on.. this is some tough shit for me.. i don't know what to do..
Hello! Try replacing this capacitor with a new one. If your monitor doesn't work, the cause of the malfunction doesn't relate to this capacitor.
@@ToolBoomVideo Maybe if he's lucky, but that's time consuming and poor repair advice. Anyone doing that for all the E-Caps on a board will go out of business doing repair, and possibly blow a new cap. An ESR meter will check for BAD capacitors on PCB (one doesn't need to measure CAPACITANCE to find BAD caps. Also check diodes and transistor junctions in the power supply section.
I agree.
This is why they invented the ESR meter...
There was nothing to invent. Circuit analysis has always considered equivalent series resistance when needed. It always has been a simple impedance measurement in the old days when electronics and especially RF circuits did not need to go into the SHF spectrum. However nowdays its very important in circuit design
So is the reading on no.6 capacitor bad enough that it needs to be replaced?
Most likely, this indicates that the capacitor is old or on the verge of working capacity. Therefore, it is better to replace it.
Title is a little misleading. I thought you were going to show a way to do it instead of showing why not to do it.
How to find smd capacitor voltage Value??
Hello! Smd capacitor voltage Value You can find in the device datasheet.
cool !!
I thought as much but having it confirmed is good so I don't waste money on my next meter.
What is the model number of the multimeter u were using in the test
Hello! UNI-T UT139C (UTM1139C): toolboom.com/en/digital-multimeter-uni-t-ut139c/
@@ToolBoomVideo thanks bro
Just use an ESR meter and you can find good or bad caps in circuit.
ESR's cannot work, thats what the video is about. That's why major multimeter makers don't sell ESR's. Watch the WHOLE video.
@@twoshedsjackson6478 I use an ESR meter all the time. Works great when measuring a capacitor's equivalent series resistance in the circuit. If your capacitor is damaged, it will show you very quickly. I use an ESR meter to make the job of finding bad caps much easier than taking each one out and testing them individually... Of course, if there is physical bulging or leaking, no meter required. Just replace the cap.
@@twoshedsjackson6478 - ESR helps troubleshoot because it shows quickly if a capacitor is out of spec. It won't give you accurate capacitance.
@@twoshedsjackson6478 in video he was measuring capacitance, nnot ESR. This is a huge difference.
@@losthor1zon You don't measure capacitance with an ESR meter.
....seems to be true...good video...
Thanks!
👍👍👍
So you desoldered a lot of good caps and now the leads are so short they can't be resoldered back to the board? I couldn't anyway, my eyes and dexterity ware waning.
We did this for demonstration purposes. However, if you try very hard, then it is quite possible. :)
Cannot measure capitacince on pcb so what gives
Misleading title.
Don't you have to first discharge the capacitor by connecting a resistor across the leads?
Good point, you're right - it's worth discharging the capacitors before testing. In our case, they were obviously discharged.
If I saw a technical presentation that abbreviated Hertz as Htz, I would wonder if the presenter had any formal, practical or academic familiarity with the topic. Same here, seeing uF (microfarads) abbreviated Mk"phi".
Hello. We apologize for this inaccuracy. The fact is that on paper "мкФ" are written in Cyrillic, which also means μF. (And "мФ"= "mF")
But electricity will follow the path of least resistance, just because you put the probes on the capacitor doesn't mean your test will on run through the capacitor of there is another path of less resistance electricity will flow that way or there may be other components in parallel or series it's not accurate test
I've just learned today that a capacitor can test good on multimeter and also very expensive capacitor testers but the capacitor in actuality is bad. I was trying to test some capacitors in my CB this morning without taking them out and most of the time I got no reading but never any accurate reading with a multimeter. That got me digging into the subject a little. MR Carlson on youtube has a brand new invention that does very well on testing capacitors and is making plans and schematics available at his paetreon channel.
if you need to measure ESR get an ESR meter
Title mislead me.
yep agreed
Not really. It proves that it cannot be done. This has saved you thousands of hours of stupidity.
Yeah, video title should have been "Proof that you cannot accurately measure capacitors in circuit" or something similar to that.
Interesting but what is that infuriating background noise?
2:11 WHY did you set a circuit board on a static paper
Hello! Thank you for your comment. However, in our case, this does not significantly affect the measurement result.
How about using an in circuit measurement tool to compare ? Watched the video which was misleading
For in-circuit measurements, you may want to consider BOKAR ST-5-S smart tweezers, which are a combination of a digital multimeter with a high precision SMD probe. Look it up here: toolboom.com/en/rlc-meter-bokar-smart-tweezers-st-5-s/
Oh yeah
Summing up the video: Measuring capacitance without desoldering capacitors from a PCB is not possible even with "special", non-official instruments. Explained in the movie why.
the multimeter is 13usd on ebay!
You could cut a fairly large piece of unnecessary video footage, stringing together a much more bearable video to watch
First of all, excellent demonstration. Secondly, I didn't even know such magical on-board measurement devices even existed, yet alone people could fall for it. I'm a beginner, but the theoretical reason you pointed out why such devices can't possibly work is something I learned very early: after being introduced to Ohm's law, it was demonstrated how resistors connected in series or in parallel can be simplified into a single equivalent resistance, and effectively they look like a single one from an external point of view (either a power supply or a measurement tool). Later it was further clarified how and why the different formulas are used, by leveraging on Kirchoff's laws, and it became very clear that it stems from how voltage and current are distributed by the different nature of the connection (series or parallel). While messing around with a couple of resistors on a breadboard to get a feel of how to test things with the multimeter, I was puzzled why I was reading a different resistance on a specific resistor which was perfectly fine when measured alone, then realized that other resistors were connected to it in parallel: it was a very "Ohhhh, now I see, silly me" moment for me :D Obviously the same holds true for any other passive component: capacitors and inductors can be treated as equivalent capacitances or equivalent inductances. Sometimes we have huge brainfarts moment (especially when you are starting to learn a new skill), I do aswell, but it baffles me how someone could buy such magical devices, and makes me question if they are able to use a plain old multimeter in the first place
Hello! Thank you for such a great review. Totally agree with you. :)
You say it can't be done when I've seen it done. Not perfect readings but more then good enough to find bad caps.
Hello! Our video is aimed to show that it is incorrect to measure the component parameters on a PCB without desoldering them.
my point is however incorrect it is using an esr tells you if cap is bad or not without taking the cap off the board. also you used a cap meter which we already know doesn't work. you should have used an esr and prove they don't work that way. your test was not relevant.
Steven Watson I was thinking the same thing. It would have been a more accurate example had he also used an ESR tester.
@@jimcabana9309 Great minds think alike ; )
@@stevenw4549 Exactly. This issue is: is the cap good or bad, which ESR will usually tell you. Electrolytics go large when they go.
Title is misleading, yes! Micro-Farad is by no means abbreviated " Mkphi"! it is µF!
It's in russian i think. If it was chinese you will see their language, so... it's not about abbreviation
You should use one of instruments that declare to be useful in such measuring.
very sure way to measure is to remove capacitor from circuit to get the correct capacitance.
you are not using right LCR METER mate .. that why you are not getting result
So he is saying it works, you only have to divide the measured value by 2.5 ;)
Hello! Please describe in more detail what you mean?
@@ToolBoomVideo exactly as he says. It isn't French
If you do this make sure your employer doesn’t see you or you’re fired.
tl;dr: No. You're welcome!
Very misleading title. A more accurate title would be "Why it's necessary to desolder capacitors in order to get an accurate reading."
I disagree. The title accurately examines the QUESTION asked in the title. Not misleading at all.