Capacitance multiplier

Another application is in DC power supplies where very low ripple voltage (under load) is of paramount importance, such as in class-A amplifiers.

Here the capacitance of capacitor C1 is multiplied by approximately the transistor's current gain (β).

Another way is to look at this circuit as an emitter follower with capacitor C1 holding voltage at base constant with load of input impedance of Q1: R2 multiplied by (1 + β), so the output current is stabilized much more against power line voltage noise.

Here, the capacitance of capacitor C1 is multiplied by the ratio of resistances: C = C1 * R1 / R2 at the Vi node.

Its function acts as a reference standard, not as a general-purpose circuit element.