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#135 - Measure Capacitor ESR with an Oscilloscope and Function Generator
WEBVTT Kind: captions Language: en
00:00:00.650 or in this video we're going to measure 00:00:03.05000:00:03.060 the equivalent series resistance of a 00:00:05.78000:00:05.790 capacitor using an oscilloscope and a 00:00:08.62900:00:08.639 function generator 00:00:09.58900:00:09.599 this also is called ESR ESR is really 00:00:13.52000:00:13.530 kind of a measure of effectively the 00:00:15.58000:00:15.590 resistance that looks like it's in 00:00:18.20000:00:18.210 series with the capacitor itself now 00:00:21.10900:00:21.119 ideally that doesn't exist but for 00:00:23.66000:00:23.670 inexpensive capacitors used at high 00:00:25.60900:00:25.619 temperatures with high ripple currents 00:00:28.07000:00:28.080 and things like that many times the 00:00:31.09900:00:31.109 capacitors a pin can begin to dry out 00:00:33.17000:00:33.180 and when that happens the resistance 00:00:37.27000:00:37.280 effectively increases which causes 00:00:40.10000:00:40.110 heating which kind of accelerates the 00:00:41.95900:00:41.969 whole process and the capacitor 00:00:43.34000:00:43.350 ultimately fails it's a pretty common 00:00:44.93000:00:44.940 failure mode so we can model that ESR 00:00:47.95900:00:47.969 kind of like this simple diagram here 00:00:50.36000:00:50.370 and reality it's a little more complex 00:00:52.40000:00:52.410 than that but for our purposes this will 00:00:54.31900:00:54.329 do the way we're going to measure the 00:00:57.43000:00:57.440 ESR is to essentially put an EC signal 00:01:00.97900:01:00.989 through the capacitor we're going to 00:01:02.59900:01:02.609 pick a frequency that's high enough that 00:01:04.16000:01:04.170 the capacitor would ideally look like 00:01:06.08000:01:06.090 nearly a short less than 1 ohm of 00:01:07.91000:01:07.920 resistance or capacitive reactance so if 00:01:10.91000:01:10.920 there is any voltage drop across the 00:01:12.56000:01:12.570 capacitor it's going to be due to the 00:01:15.67900:01:15.689 ESR and not due to the capacitive 00:01:17.99000:01:18.000 reactance ideally okay so we're going to 00:01:21.02000:01:21.030 use a function generator now most 00:01:22.58000:01:22.590 function generators can be modeled kind 00:01:24.85900:01:24.869 of in this way where you've got an ideal 00:01:26.92900:01:26.939 voltage source in this case a square 00:01:28.60900:01:28.619 wave followed by a 50 ohm output 00:01:31.19000:01:31.200 resistor so it gives them a 50 mm output 00:01:34.24900:01:34.259 impedance now it's going to be important 00:01:36.31900:01:36.329 to know what the output impedance is or 00:01:38.39000:01:38.400 at least to verify that yours is 50 ohms 00:01:40.39900:01:40.409 or something else before you go do the 00:01:42.83000:01:42.840 measurement but because we're going to 00:01:44.63000:01:44.640 use this later on when we go to 00:01:46.01000:01:46.020 calculate things when we set up the 00:01:48.80000:01:48.810 function generator we're going to use a 00:01:50.03000:01:50.040 frequency I like you know somewhere 00:01:52.03900:01:52.049 between 100 and 300 kilohertz because at 00:01:55.73000:01:55.740 that frequency the electrolytic 00:01:57.56000:01:57.570 capacitors that were typically 00:01:58.81900:01:58.829 interested in will have a capacitive 00:02:01.58000:02:01.590 reactance less than 1 ohm if we pick 200 00:02:05.63000:02:05.640 kilohertz you know you're looking at 00:02:07.03900:02:07.049 typically 10 micro farad or larger 00:02:08.74900:02:08.759 capacitors the reactance is going to be 00:02:10.94000:02:10.950 low so a good capacitor is going to look 00:02:13.19000:02:13.200 like 00:02:13.97000:02:13.980 and it's not going to generate any 00:02:15.22900:02:15.239 voltage across it when you connect it up 00:02:16.88000:02:16.890 to the function generator but this 00:02:19.30900:02:19.319 frequency is also low enough that we can 00:02:21.25900:02:21.269 kind of ignore any transmission line 00:02:23.47900:02:23.489 effects reflections and that kind of 00:02:25.49000:02:25.500 thing we don't have to properly 00:02:26.60000:02:26.610 terminate the lines and such so that's a 00:02:29.14900:02:29.159 pretty good compromise I'm going to use 00:02:31.72900:02:31.739 a volt peak-to-peak because that's 00:02:33.05000:02:33.060 pretty good for out of circuit testing 00:02:34.64000:02:34.650 if you really want to try doing in 00:02:36.55900:02:36.569 circuit testing you probably want to go 00:02:38.00000:02:38.010 to two to three hundred milli volts 00:02:39.86000:02:39.870 peak-to-peak maximum but I don't really 00:02:42.50000:02:42.510 recommend in circuit testing so let's 00:02:45.28900:02:45.299 take a look at how we're going to set 00:02:47.80900:02:47.819 this measurement up okay in order to set 00:02:50.50900:02:50.519 this up first thing we're going to do is 00:02:52.22000:02:52.230 set the amplitude of our function 00:02:54.37900:02:54.389 generator we'll just connect it right up 00:02:56.27000:02:56.280 to the scope you can use a probe or you 00:02:58.12900:02:58.139 can go right into the high input 00:02:59.69000:02:59.700 impedance input of the scope again we're 00:03:02.14900:03:02.159 using a low enough frequency that we 00:03:03.50000:03:03.510 don't have to worry about putting a 50 00:03:06.02000:03:06.030 ohm termination there so what you want 00:03:08.75000:03:08.760 to do is set it up for about 200 00:03:10.25000:03:10.260 kilohertz and the voltage to vary 00:03:12.53000:03:12.540 between ground and your peak to peak 00:03:14.27000:03:14.280 voltage say 1 volt peak-to-peak and then 00:03:16.49000:03:16.500 back down again you don't want to go 00:03:18.31900:03:18.329 below ground and reverse bias the our 00:03:20.47900:03:20.489 capacitor under test so we do that first 00:03:23.11900:03:23.129 the next thing we can do is simply put a 00:03:26.72000:03:26.730 resistor now soothly put our capacitor 00:03:28.90900:03:28.919 under test right across the output of 00:03:31.46000:03:31.470 the function generator and we'll do that 00:03:32.93000:03:32.940 right at the front of the input of the 00:03:34.81900:03:34.829 scope and I'll show you how we'll do 00:03:35.96000:03:35.970 that now ideally the capacitor should 00:03:39.40900:03:39.419 have no equivalent series resistance and 00:03:42.11000:03:42.120 the capacitive reactance should be well 00:03:44.71900:03:44.729 under 1 ohm so that as soon as you 00:03:46.58000:03:46.590 connect that capacitor up the output as 00:03:48.61900:03:48.629 seen on the scope should go to nearly 00:03:50.08900:03:50.099 nothing okay now what will happen is if 00:03:53.71900:03:53.729 a capacitor has some equivalent series 00:03:57.11000:03:57.120 resistance that's measurable a couple of 00:03:58.78900:03:58.799 ohms or more the capacitor might look 00:04:01.64000:04:01.650 like a short but the ESR component will 00:04:03.94900:04:03.959 not and a voltage will be generated 00:04:05.99000:04:06.000 across that and by measuring that 00:04:07.90900:04:07.919 voltage with the scope compare and then 00:04:09.86000:04:09.870 it's a simple voltage divider 00:04:11.80000:04:11.810 calculation to you know extract what 00:04:15.11000:04:15.120 that equivalent series resistance is but 00:04:18.43900:04:18.449 the reality is is that often times as 00:04:20.39000:04:20.400 these capacitors dry out and the ESR 00:04:22.55000:04:22.560 goes up the capacitance also goes down 00:04:26.65000:04:26.660 you know the capacitors will be reduced 00:04:28.48000:04:28.490 in value so what will happen is this 00:04:30.82000:04:30.830 capacitor might get low enough they will 00:04:33.37000:04:33.380 start to see the RC charging time 00:04:36.07000:04:36.080 constant you know instead of you know a 00:04:39.28000:04:39.290 nice low impedance and you can see a 00:04:41.53000:04:41.540 combination of that I'll show you what 00:04:42.73000:04:42.740 that would look like in a moment now 00:04:45.70000:04:45.710 many ESR meters including the one that I 00:04:47.77000:04:47.780 built a few years ago and did a video on 00:04:49.78000:04:49.790 I'll put a link to that by the way down 00:04:51.76000:04:51.770 below will measure the response of that 00:04:56.35000:04:56.360 RC exponential as well as the ESR but at 00:05:00.25000:05:00.260 the end of the day that's okay because 00:05:02.11000:05:02.120 in either case the capacitor is bad and 00:05:05.59000:05:05.600 you're going to want to replace it so 00:05:07.93000:05:07.940 here's what we're going to do we're 00:05:09.13000:05:09.140 going to have our function generator 00:05:10.45000:05:10.460 we'll start off by measuring just the 00:05:12.01000:05:12.020 voltage without a capacitor connected to 00:05:14.26000:05:14.270 it but then when we connect our 00:05:15.94000:05:15.950 capacitor up we're going to see one of 00:05:17.35000:05:17.360 two things we're either going to see 00:05:18.94000:05:18.950 just a reduced square wave on the scope 00:05:21.94000:05:21.950 and then the voltage there is really the 00:05:24.73000:05:24.740 voltage across the resistance the 00:05:26.65000:05:26.660 equivalent series resistance because the 00:05:28.90000:05:28.910 capacitor looks like a short at those 00:05:30.46000:05:30.470 frequencies but often times what you'll 00:05:32.74000:05:32.750 see is a combination of the effects 00:05:34.21000:05:34.220 you'll see a step change that's due to 00:05:37.21000:05:37.220 the ESR but you'll also see an 00:05:39.22000:05:39.230 exponential rise in an exponential fall 00:05:41.41000:05:41.420 on either end of the step change that 00:05:45.16000:05:45.170 indicates that you essentially have got 00:05:47.35000:05:47.360 a much lower value of capacitance and 00:05:49.84000:05:49.850 you're seeing essentially the RC time 00:05:51.73000:05:51.740 constant of this combined resistance and 00:05:54.73000:05:54.740 the capacitance but in either case you 00:05:57.37000:05:57.380 know what this is showing you is you're 00:05:59.02000:05:59.030 going to be generating some voltage or 00:06:00.64000:06:00.650 dropping some voltage across this 00:06:02.41000:06:02.420 capacitor what ideally it should look 00:06:04.54000:06:04.550 like a short and you shouldn't develop 00:06:05.98000:06:05.990 anything so this is the arrangement 00:06:08.35000:06:08.360 we'll use to make the measurements this 00:06:10.63000:06:10.640 the end of this coax here runs back to 00:06:12.52000:06:12.530 my function generator is back over my 00:06:14.47000:06:14.480 shoulder I'm just going into a little 00:06:16.75000:06:16.760 BNCT one end that I'm going to couple 00:06:19.93000:06:19.940 right into the scope input the other end 00:06:22.27000:06:22.280 connected up to a set of Miniclip leads 00:06:25.09000:06:25.100 that we use to connect to our capacitor 00:06:27.46000:06:27.470 under test 00:06:28.06000:06:28.070 so without anything connected here if we 00:06:30.94000:06:30.950 just hook this up to the input of the 00:06:32.74000:06:32.750 scope I can see the response of my 00:06:37.03000:06:37.040 function generator I'm at 200 millivolts 00:06:39.82000:06:39.830 of division 00:06:40.45000:06:40.460 so that's five divisions that I've got 00:06:42.46000:06:42.470 one volt peak-to-peak now if I 00:06:44.44000:06:44.450 momentarily couple the scope to ground I 00:06:46.48000:06:46.490 can see that's where ground is so this 00:06:49.57000:06:49.580 voltage is varying from ground up to a 00:06:51.85000:06:51.860 volt and then back down the ground so 00:06:54.67000:06:54.680 again we're not reverse biasing it so 00:06:56.83000:06:56.840 that's the proper setup to get ready to 00:07:00.13000:07:00.140 make the ESR measurements all right 00:07:02.92000:07:02.930 starting off with a good capacitor so 00:07:04.93000:07:04.940 you know what you want to see is we're 00:07:07.12000:07:07.130 just going to take this 220 micro farad 00:07:09.67000:07:09.680 capacitor note that this is the 00:07:12.01000:07:12.020 indication here for where the negative 00:07:14.14000:07:14.150 lead is so we'll connect the black gram 00:07:17.53000:07:17.540 a black mini grabber lead up to that and 00:07:21.72000:07:21.730 then we'll take the the other lead and 00:07:24.34000:07:24.350 hook it up to the other end and watch 00:07:26.05000:07:26.060 what happens on the scope screen so we 00:07:28.81000:07:28.820 effectively you know nearly completely 00:07:31.06000:07:31.070 squashed that signal we're going to see 00:07:33.13000:07:33.140 the average value of it and that's 00:07:34.39000:07:34.400 normal 00:07:35.02000:07:35.030 we're also going to see a couple of 00:07:37.21000:07:37.220 little blips right at the edge 00:07:38.74000:07:38.750 transitions and if we look carefully if 00:07:40.69000:07:40.700 I turn the intensity up I'm able to see 00:07:42.94000:07:42.950 those little blips here and here and 00:07:44.68000:07:44.690 here 00:07:45.10000:07:45.110 now that's normal what we're looking at 00:07:47.62000:07:47.630 is the you know the fact that we're not 00:07:50.62000:07:50.630 terminating this this coax properly 00:07:52.90000:07:52.910 there's a little bit of reflection 00:07:54.43000:07:54.440 coming back off of these leads a little 00:07:56.89000:07:56.900 bit of inductance in series with the 00:07:58.51000:07:58.520 capacitor so you're going to get that no 00:08:01.03000:08:01.040 big deal but ideally what we've seen is 00:08:03.49000:08:03.500 that we've taken the top and brought it 00:08:04.93000:08:04.940 down the bottom brought it up those two 00:08:07.12000:08:07.130 are effectively at the same level if 00:08:09.49000:08:09.500 there was some effective series 00:08:11.56000:08:11.570 resistance there we would have a 00:08:13.93000:08:13.940 difference between the high and the low 00:08:16.15000:08:16.160 level so this is what a good capacitor 00:08:18.82000:08:18.830 looks like so let's take a look at even 00:08:22.06000:08:22.070 a little bit closer in here what we can 00:08:23.53000:08:23.540 do is change the scope to be AC coupled 00:08:26.61000:08:26.620 all right we'll move our position up and 00:08:29.65000:08:29.660 then turn up our volts per tor turn down 00:08:32.80000:08:32.810 the volts per division to get a little 00:08:34.30000:08:34.310 bit more magnification on this and now 00:08:36.70000:08:36.710 you can actually see a little bit of the 00:08:39.34000:08:39.350 kind of the step change due to those 00:08:42.88000:08:42.890 inductance components that we talked 00:08:44.32000:08:44.330 about I can see a very small change like 00:08:47.08000:08:47.090 if we go to even smaller I can see a 00:08:48.94000:08:48.950 very small change here I'm at 10 00:08:50.56000:08:50.570 millivolts a division 00:08:52.21000:08:52.220 okay so we can see a very small voltage 00:08:55.12000:08:55.130 change here in fact if we put a couple 00:08:57.10000:08:57.110 of voltage cursors on here we go take a 00:08:59.08000:08:59.090 look 00:08:59.38000:08:59.390 now I'm measuring about three millivolts 00:09:01.75000:09:01.760 so we've taken that one volt 00:09:03.31000:09:03.320 peak-to-peak square wave and reduce it 00:09:06.04000:09:06.050 down to three millivolts that's pretty 00:09:08.23000:09:08.240 insignificant this is a pretty darn 00:09:10.33000:09:10.340 close to a short so we're looking at 00:09:12.76000:09:12.770 well under 1 ohm of equivalent series 00:09:15.37000:09:15.380 resistance with this good capacitor so 00:09:18.28000:09:18.290 let's go look at one that's not so good 00:09:19.72000:09:19.730 this is actually a good capacitor brand 00:09:23.02000:09:23.030 new it's just a lot physically a lot 00:09:25.93000:09:25.940 smaller and typically as the capacitor 00:09:28.24000:09:28.250 gets smaller for the same value they're 00:09:31.21000:09:31.220 going to have an equivalent resistance 00:09:33.49000:09:33.500 and you can see that here on the screen 00:09:35.11000:09:35.120 that this one is dropping about eight 00:09:37.66000:09:37.670 millivolts nine millivolts from that one 00:09:40.60000:09:40.610 volt peak-to-peak signal so while it's 00:09:43.00000:09:43.010 not a bad capacitor the capacitance is 00:09:44.92000:09:44.930 still good it's just the fact that it's 00:09:47.89000:09:47.900 physically smaller you will naturally 00:09:50.02000:09:50.030 see a larger ESR because the plates are 00:09:52.51000:09:52.520 physically smaller it will have larger 00:09:54.16000:09:54.170 resistance but this is the same type of 00:09:57.64000:09:57.650 shape that you'd see that just might be 00:09:59.98000:09:59.990 large or an amplitude when you've got a 00:10:02.05000:10:02.060 capacitor that has even a higher series 00:10:04.00000:10:04.010 resistance so let's go look at a 00:10:06.31000:10:06.320 capacitor that I pulled out of an old 00:10:08.05000:10:08.060 monitor that actually failed you'll see 00:10:11.26000:10:11.270 now that this bad capacitor in here I've 00:10:13.90000:10:13.910 actually got to bring my volts per 00:10:16.03000:10:16.040 division back up again so I can actually 00:10:18.07000:10:18.080 see what's going on so with this one 00:10:20.26000:10:20.270 this we can kind of see that effect that 00:10:21.85000:10:21.860 I mentioned earlier where we have a step 00:10:24.16000:10:24.170 change due to the ESR but then an 00:10:27.31000:10:27.320 exponential change due to the reduced 00:10:29.29000:10:29.300 capacitance so this this was a failed 00:10:32.02000:10:32.030 capacitor if we look carefully at it you 00:10:34.18000:10:34.190 might be able to see the top of it is 00:10:35.50000:10:35.510 domed out it you know it kind of got hot 00:10:37.57000:10:37.580 and overheated and dried out it's just a 00:10:40.21000:10:40.220 nasty capacitor but if we look at the 00:10:42.40000:10:42.410 peak to peak voltage of this say from 00:10:44.47000:10:44.480 down here all the way up here worried 00:10:46.84000:10:46.850 about a hundred millivolts so that one 00:10:50.41000:10:50.420 volt peak-to-peak signal was only 00:10:51.97000:10:51.980 brought down to to 113 millivolts here 00:10:54.73000:10:54.740 now so this capacitor certainly bad now 00:10:58.15000:10:58.160 what's funny is that if you measure the 00:10:59.98000:10:59.990 capacitance of this it might look you 00:11:02.56000:11:02.570 know larger than you might it might 00:11:05.17000:11:05.180 appear from this 00:11:06.07000:11:06.080 RC time constant but that's just due to 00:11:08.17000:11:08.180 the fact that when these things dry out 00:11:09.79000:11:09.800 the capacity resistance is not or the 00:11:12.49000:11:12.500 resistance increase is not evenly 00:11:14.35000:11:14.360 distributed across the plates and you 00:11:16.48000:11:16.490 get a little more of a complex thing 00:11:18.04000:11:18.050 going on but at the end of the day that 00:11:20.41000:11:20.420 would be a bad capacitor leaving that on 00:11:22.90000:11:22.910 the same scale just to kind of give you 00:11:24.58000:11:24.590 some perspective let's go back and take 00:11:26.35000:11:26.360 our good capacitor and take a look at 00:11:28.57000:11:28.580 what that one would look like under that 00:11:30.88000:11:30.890 same scale okay so you have that same 00:11:34.27000:11:34.280 scale you can see how much better this 00:11:36.37000:11:36.380 capacitor is so if you if you're 00:11:39.25000:11:39.260 interested in trying to calculate out 00:11:40.96000:11:40.970 what that equivalent series resistance 00:11:42.10000:11:42.110 is just stick around for the next part 00:11:44.86000:11:44.870 of the video if not that's basically how 00:11:47.17000:11:47.180 you do the measurements so let's go take 00:11:49.63000:11:49.640 a look and see what those calculations 00:11:50.92000:11:50.930 look like it's really quite simple 00:11:52.83000:11:52.840 alright to calculate the equivalent 00:11:55.18000:11:55.190 series resistance it really is just a 00:11:57.25000:11:57.260 voltage divider calculation right and 00:12:00.70000:12:00.710 we're looking for this resistor value we 00:12:03.01000:12:03.020 know what this function generator ideal 00:12:05.08000:12:05.090 voltage is we know the output impedance 00:12:07.24000:12:07.250 is 50 ohms we just don't know they are 00:12:09.27000:12:09.280 so that the typical voltage divider 00:12:11.92000:12:11.930 calculation would be you know the 00:12:13.87000:12:13.880 function generator voltage multiplied by 00:12:16.72000:12:16.730 that resistance divided by the sum of 00:12:18.97000:12:18.980 the resistances gives us that voltage 00:12:21.67000:12:21.680 which we'll call V R now we know what V 00:12:25.72000:12:25.730 R is we've measured it okay we know what 00:12:28.12000:12:28.130 the function generator voltage is we've 00:12:30.13000:12:30.140 measured it we just need to solve for R 00:12:32.17000:12:32.180 so we can simply run that equation or 00:12:35.11000:12:35.120 rearrange that equation like this and 00:12:37.95000:12:37.960 we're going to rearrange the equation as 00:12:40.30000:12:40.310 such we wind up with this equation here 00:12:42.19000:12:42.200 that says the ESR is equal to the 00:12:44.80000:12:44.810 measured voltage across the capacitor 00:12:48.90000:12:48.910 multiplied by 50 divided by the open 00:12:52.39000:12:52.400 circuit voltage of the function 00:12:53.62000:12:53.630 generator minus VR or our measured 00:12:56.56000:12:56.570 voltage so let's run that calculation 00:12:58.93000:12:58.940 for the bad capacitor that we measured 00:13:01.63000:13:01.640 that was putting 113 millivolts across 00:13:04.90000:13:04.910 the cross itself okay so we know we 00:13:10.75000:13:10.760 measured 113 millivolts and we'll 00:13:14.08000:13:14.090 multiply that by 50 00:13:16.15000:13:16.160 and then we're going to divide that by 00:13:17.91000:13:17.920 that we have one volt peak-to-peak minus 00:13:21.25000:13:21.260 the point 1 1 3 volts divide that we 00:13:25.27000:13:25.280 wind up with about six point three ohms 00:13:27.13000:13:27.140 of ESR for that particular capacitor 00:13:31.21000:13:31.220 let's go take a look at what I measure 00:13:33.19000:13:33.200 on my homebrew ESR meter for that bad 00:13:37.75000:13:37.760 capacitor here's my little homebrew ESR 00:13:42.13000:13:42.140 meter let's make sure that it's zeroed 00:13:43.87000:13:43.880 properly we'll short the leads together 00:13:45.22000:13:45.230 and it looks like we're or zero properly 00:13:48.79000:13:48.800 there so let's connect up that that bad 00:13:52.33000:13:52.340 capacitor so I've got the negative lead 00:13:55.36000:13:55.370 going to the negative side positive lead 00:13:58.06000:13:58.070 to the positive side here if we take a 00:14:00.61000:14:00.620 look it's actually you've got a little 00:14:02.68000:14:02.690 bit of parallax you're looking off to 00:14:03.94000:14:03.950 the side from here but if I pull this 00:14:05.59000:14:05.600 over you can see it's just a little bit 00:14:07.24000:14:07.250 greater than five ohms close to 6 ohms 00:14:09.61000:14:09.620 there so this meter is basically 00:14:12.64000:14:12.650 measuring that peak to peak value are 00:14:14.89000:14:14.900 pretty close to it of that response that 00:14:20.02000:14:20.030 we're seeing on this back capacitor they 00:14:21.85000:14:21.860 get a lot of ESR meters will do that but 00:14:23.83000:14:23.840 at the end of the day that value is much 00:14:26.08000:14:26.090 higher than you'd want to see on a good 00:14:27.64000:14:27.650 capacitor if we connect up my good 00:14:29.68000:14:29.690 capacitor here 00:14:30.70000:14:30.710 let's same that same way okay so here's 00:14:35.71000:14:35.720 the ESR that good capacitor you can see 00:14:37.72000:14:37.730 that looks pretty darn near or short so 00:14:40.51000:14:40.520 if you don't want to go and build one of 00:14:42.37000:14:42.380 these things and you have a function 00:14:43.81000:14:43.820 generator and an oscilloscope you can 00:14:46.06000:14:46.070 very easily measure what the ESR is or 00:14:49.39000:14:49.400 just at least to check whether a 00:14:50.80000:14:50.810 capacitor is good or bad anyway thanks 00:14:53.53000:14:53.540 for watching and oscillator
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