testing stiffening caps
#1
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Is there a way of testing a stiffening cap? Say for instance, you are given a cap with no label on it. How can you test it to see how many farad's it is or if it is even doing anything? or if it is labeled is it actually the value the manufacturer claims?
#4
Before you do any testing make sure that the cap is fully discharged the easiest way to do that is to ground your test light via the gator clip, now touch the tip of the test light to the capacitors terminal, if charged the bulb will light up but will fade and eventually go out telling you the cap is discharged! I apologize if you already know this but damn it can cause real headaches to someone who hasn't handled one before and if you have, maybe a newbe will read this and save themselves a disaster!
#5
Hmmm charge it up and see if it holds the charge... be carefull though, if it's only rated for 12V surge it could blow up on you if you give it 14V +
edit: where did you get it anyway ?
As far as measuring capacitance.. I don't think many DMMs will measure that high... my fluke only measures up to 10K uF.... (.01F)
I think the easiest way for you to measure your cap is to measure the RC time constant....
charge your cap through a resistor from 0 volts and note how long it takes the cap voltage to reach 63% of the charging voltage. Then use the formula: Capacitance = Time / Resistance
(Capacitance is in farads when T is in seconds and R is in ohms)
[img]graemlins/thumb.gif[/img]
[ November 17, 2005, 11:01 AM: Message edited by: Haunz ]
edit: where did you get it anyway ?
As far as measuring capacitance.. I don't think many DMMs will measure that high... my fluke only measures up to 10K uF.... (.01F)
I think the easiest way for you to measure your cap is to measure the RC time constant....
charge your cap through a resistor from 0 volts and note how long it takes the cap voltage to reach 63% of the charging voltage. Then use the formula: Capacitance = Time / Resistance
(Capacitance is in farads when T is in seconds and R is in ohms)
[img]graemlins/thumb.gif[/img]
[ November 17, 2005, 11:01 AM: Message edited by: Haunz ]
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