Measurement of capacitance

[gettering]

Hi,

When capacitance is measured, forward and reverse bias is applied alternatively. Could you tell me why this is requried for the measurement? In my opinion, charge stored in capacitance would not be released even though dc voltage is applied. and could you tell me how capacitance meter works roughly? Thank you.

 

[OperaHouse]

A bias is applied because this is normal way a capacitor would be used in the case of an electrolytic which is polarized. The ESR of a capacitor has as much more to do with how the molecules react to a field as internal resistance associated with construction. Some materials have a piezoelectric effect when a voltage is applied to them and change thickness and capacitance. A large number of sophisticated capacitance measuring instruments are sold for applications in material science and never get near a component capacitor.

 

[IRstuff]

Of course, capacitance meters must also measure capacitors that have both hysteresis and nonlinearities in capacitance, ala MOS capacitors.

TTFN

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