Capacity multiplier

A capacitance multiplier is an electronic circuit whose electrical capacitance is many times higher or lower than the capacitance of the capacitor installed in it , so that a capacitor with a different capacitance is created. It is a matter of multiplying an existing capacity C _c with a constant factor k in order to form the higher capacity C :

Capacitance multiplier with transistor

Capacitance multiplier with operational amplifier

${\displaystyle C=k\cdot C_{c}}$

The capacity multiplier is therefore in the ideal case a positive impedance converter (PIC).

A bipolar transistor Q with the current amplification factor β can be used as a multiplier :

${\displaystyle C=\beta _{Q}\cdot C_{1}}$

Alternatively, an operational amplifier with the following relationship can be used:

${\displaystyle C={\frac {R_{1}+R_{2}}{R_{2}}}\cdot C_{1}}$

Capacitance multipliers are suitable, for example, for generating a particularly stable DC voltage with little effort, some non-ideal properties of a capacitor being omitted.

Web links

• Java applet animated capacity multiplier