Research Trends and Challenges in Physical Science Vol. 1,
26 August 2021,
The objective of the paper is to propose and study the modified version of NPN-driven Sziklai pair small-signal amplifier with user-defined PSpice model of unmatched BJTs. With an additional biasing resistance, the proposed amplifier generates higher amplifier current gain (12904), higher amplifier voltage gain (304.343), wider bandwidth (2.7107 MHz) and higher power gain (65.940 dB-Watt) than earlier announced commercial BJTs based NPN Sziklai pair Small-signal amplifier. It is also found capable of producing distortion-less and fair output for a 1\(\mu\)V-1.6mV range of AC input signal at 1KHz frequency. Low input and output noises along with excellent thermal stability over the operational temperature range -30oC \(\le\)T\(\le\)+50oC are the paramount features of this amplifier. Proposed amplifier is also examined with the matched pair of BJTs. An investigation of the physical analysis of frequency responses and related parameters such as the effect of additional biasing resistance RA, effect of variation of current gain factor \(\beta\), temperature dependency, noise sensitivity, phase variation, range of the different biasing resistances and capacitors and small-signal AC analysis is also being performed in detail. With the suggested modifications, the proposed amplifier may be used in analog front-end amplifiers for monitoring the bio-potential signal of the human body. Tuning performance also makes it a suitable candidate to be used in radio and TV receiver stages.