Qualitative study of a new circuit model of small-signal amplifier using Sziklai pair in compound configuration

A new circuit model of small-signal wide-band voltage amplifier using Sziklai pair is proposed for the first time. The proposed amplifier circuit uses two PNP and one NPN transistors and two additional biasing resistances in its configuration. The upper half of the triple transistor system with transistors Q1 and Q2 constitute a Sziklai pair while the lower half with Q2 and Q3 forms complementary Sziklai pair. The over-all performance of the proposed amplifier circuit is found to be superior than conventional or modified small-signal Darlington and Sziklai pair amplifiers and as a rare feature the proposed circuit simultaneously produces high voltage gain and wide bandwidth. Poor response of small-signal Darlington pair amplifiers at higher frequencies and narrow bandwidth problem of small-signal Sziklai pair amplifier is found to be absent in the proposed amplifier. Variations in voltage gain as a function of frequency and different biasing resistances, bandwidth and total harmonic distortion of the amplifier is also pursued. Proposed amplifier may be useful for various analog communication applications.