Theory and Application of Parallel-T Resistance-Capacitance Frequency-Selective Networks

This paper deals with the theory and application of the parallel-T resistance-capacitance network, and gives a more general treatment of this network than that found in earlier papers. Using wye-delta conversion methods, the parallel-T resistance-capacitance network is represented by a single equivalent pi circuit. By introducing symbols corresponding to frequency and component values, simple expressions are derived for the impedance of the pi arms, as well as the network transmission, at any frequency. Since no arbitrary relationships are assumed between component values, the derived expressions are general. The practical application of the network is also considered. Three versatile circuit embodiments are described, and the effects of deviating from specified component values investigated. A calculation is made to illustrate the application of the network to a negative-feedback circuit using a single stage of voltage amplification.