Ok guys I asked my apprentice this today and he was able to give me a somewhat decent answer so let's see who the smart ones are out there in yahoo land. How does a capacitor tester get its read ? What does it do to test a capacitor?
2007-09-04 07:58:15 · 3 answers · asked by Jimmy F 3 in Science & Mathematics ➔ Engineering
The cheap cap. meters connect the unknown capacitance to an RC oscillator, or timer, and measure the frequency of oscillation. If you know the 'R', and know the formula for frequency in the particular oscillator, you can derive the unknown 'C'.
Others use a constant current source and apply it to the unknown 'C'. If the current is accurately known, then the time to charge 'C' to some point can also be known (becuase the charge rate is a linear function with a constant current).
.
2007-09-04 08:34:12 · answer #1 · answered by tlbs101 7 · 0⤊ 0⤋
To test a capacitor
measure the capacity in pf or nF or uF or mF
measure parallel resistance, (or the leakage current at the rated voltage)
measure the loss angle or Q
measure the internal series resistance
If intended for use at high frequencies
the self inductance is also important
Types ...there are many, here are two extremes
solid : Eg metallised polyester, silver mica, polypropylene
wet : aluminium electrolytics
A typical tester will not measure all parameters
I read the answers so far, they give most of the techniques to do the basic capacitance measurement
2007-09-04 16:12:19 · answer #2 · answered by Anonymous · 0⤊ 0⤋
They work by connecting the cap with a known inductance value and measuring the resonant frequency. Then calculate the capacitance from: f=1/(2*pi*sqrt(L*C)).
2007-09-04 15:21:57 · answer #3 · answered by big_bad_john 1 · 0⤊ 0⤋