how to read a cap?

hey guys at the cpa test for getting your compagnion class there is multible tests and one includes a capacitor on this wall and you need to test it with a multimeter to find out what is the mesument of it..

i used to know how but i havent done this in a long time..

does anybody know how to test this with a normal multimer?
what i remember is to see if it is good you put it on the diode setting,if it gives you an infinit reading then it is good.

but to know what exacly it is im lost..



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techker

To my knowledge, you can't measure a cap with just a DMM unless it has the socket to do so.
You can however measure the RC time constant.
For this you need a resistor of choice whose value is known, a DMM and a stopwatch . . . and our cap of course.
The RC formula is: T=R*C
Re-arrange the formula so that C=T/R
T is the time in seconds required to charge the cap to 63% of the batt voltage, and R is resistance in ohms, and C is capacitance in farads.
Fully discharge the cap. Then with an inline switch to aid precision, charge your cap through your resistor, and using the stopwatch, calculate how long it takes the voltage to build from 0 volts to 63% of the battery voltage using the formula: C=T/R

This is the only way I know how.

If someone else has a genius or simpler method (using a standard DMM) then we'll all learn something tonite.

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Prepare your future. It wasn't the lack of stones that killed the stone age.

thats funny?cause the on the test u have to read it?

maybe to find the uf?

or is there a way to see if it is good?

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techker

what are you trying to measure? if you want to measure capacitance some dmm's have that function. if you want to determine if the cap is good, use the ohm's function. a cap will appear as a short until it is charged. you should see the ohm's value increase if the cap is good. observe polarity if the cap is polarized.

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Prove your connections, use a meter!
I promise, I'll behave!

if you want to measure capacitance some dmm's have that function

what function?

thx for the info

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techker

techker wrote:

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if you want to measure capacitance some dmm's have that function

what function?

thx for the info

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measure capacitance function. there's a symbol for a cap on such meters.

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Prove your connections, use a meter!
I promise, I'll behave!