Sensitivity in some simple RC active networks

Five different RC active networks are considered, each of which produces a second-order low-pass transfer function. Two of the networks use positive feedback (one from an amplifier of nominally unity gain); two use negative feedback (one from an amplifier of nominally infinite gain); and the fifth uses a negative-impedance convertor. Equations are developed for the sensitivity of each circuit to its active and passive components, and these are compared with those for the sensitivity of a passive LCR circuit. The four active circuits using conventional amplifiers are also compared in terms of the total error in the transfer-function amplitude caused by given errors in the gain and feedback of the amplifier used.