How To Measure A Capacitor With An Oscilloscope.




What do you think about this video?

JMParsell: Thank you for your kind, intelligent, and inspiring videos.

broderp: Too bad they can't build in this feature into a scope. All is would take is some small switching resistors, a test signal built in and the firmware to have dedicated cursor measuring and readouts.

Afrah Salim: great ^:^

Sebastian Gruber-Kersting: The problem starts with measuring time accurate in the first place. Your scope might provide something like +-30ppm to +-100ppm accuracy from it's Quarz, cause it might not contain an OXCO of some hundrets of Dollar. Next problem is that your resistor might not be one of the higly precise (0.005% Tolerance - 2ppm per C°) type for some hundrets of Dollar per piece as well. Not to mention parasitic & stray capacitance and resistance in your setup caused by probes and else. Any capacitor charging while measured by inaccurate time and also inaccurate input resistance will not allow to create any result of reasonable precision. But at least the principle is very correct and well explained. Well done! Perhaps you try at least some precision resistors of 0,1% tolerance to it's value for the charging. By the way oscilloscopes are very bad devices for measuring DC in general!

Birdman: Is the resistor and the function generator necessary to test a capacitor? Why can't just touching the probes to the capacitors polarized leads do the job?

Michael Jordan: Brilliant!

War Planner: Mr Lorton, I echo the compliments on this video. Would hasten to point out that those attempting to this on a scope without cursors are royally screwed!

But then again, the killer is determining the "e level" or the 62.3% point.

But great kudos for showing us this method and your "failures" as well.

Faidul Islam: your hand paper text, print can't show

FOLLOWTHEROAD: I am sure someone must have mentioned this but I have not seen it so here goes: When using very large or very small numbers such as you are doing here it is very useful to use exponential notation. It will save a lot of errors counting zeros and decimal points. Just my pico-cents. Cheers

alex castro: two questions,,,,,1.- you can check te capacitance only whit internal resistence the function generator (50 ohms) or is necesari add the other resistor? 2.- test the any capacitance whit same frecuence? or the frecuence change whit diferent capacitance for test?

Max Power: i'm a computer engineer and i found this videos very useful for me ,thanks for illustration .

Denis Francoeur: The resistor value that you used is a 10 Megohm not a 1Megohm, that is why you have an error, look at your video you'll note that the colors stripe are Brown, Black, Blue

offgridpower: You're a brilliant teacher, thanks for sharing your knowledge with everyone.

Imad Jawad: Thanks Martin:)

Caveman Al Toraboran: 3:25 freaking video finally starts here.

Caveman Al Toraboran: Dude you talk too much freaks sake. Great video otherwise.

marc wischkaemper: Very nice tutorial. Mad scope skills!

Jay Yang: jay yang

Popart 2015: The problem is that water is used as analogy to electricity instead of gas, because water is practically incompressible contrary to gas. A capacitor should bee seen as a gas cylinder instead of a bucket. This way you may do a better analogy, like this:

V = Gas pressure;
Q = Gas quantity;
C = Capacity of Gas storage for a given pressure, and so Q/V.

Like a gas cylinder, greater pressure (V) means that greater quantity (Q) may be stored, however, if you increase V (gas pressure) too much, it blows up, so, besides C a capacitor has also defined the maximum pressure V it can handle before it blows up...
This is why you should think in electricity as Gas flow instead of Water flow.

LM: Great job Martin! thank you so much for explaining this very important concept. I like the way you go, explain the concept first then go to real world example, better yet, step by step. It is nice too that you along the way make mistakes and comment on that later so we can learn from that too. Way to go! keep up with the good work!

Schools: Learn how to get phlebotomy training in California! The job pays decent money for the amount of schools needed to graduate.
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How to measure a capacitor with an oscilloscope.