To propose a design parameter γ, resistor transfer parameter for UJT which shows resemblance with BJT

Abstract

We propose a design parameter (γ), named as resistance transfer parameter, which illustrate a resistance transfer phenomenon among emitter terminal and the base terminal B1, in the unijunction transistor (UJT). To demonstrate the phenomena in UJT, a circuit design is proposed which is based on basic circuit of relaxation oscillator employing UJT. However an additional resistor is employed at the emitter terminal which shows reflection at the base terminal. The proposed resistance phenomena in UJT is observed through simulation results and verified experimentally on the actual hardware by building the proposed relaxation oscillator design on a bread board. The experimental results verify our proposed phenomenon in UJT. We have performed experiments to check variation with supply voltage and to analyze variation with change in Re and Rb1, which verify our proposed phenomenon that the resistance at emitter gets reflected at base B1. Thus we propose a new design parameter for UJT, resistance transfer parameter (γ) which governs the transfer of emitter resistance to the terminal B1 of the UJT. The proposed phenomena and transfer parameter (γ) of UJT resembles with the behavior of bipolar junction transistor (BJT), which in turn verify our proposed phenomenon. Moreover our modified relaxation oscillator generates wide duration pulses which in turn can be used in various applications like SCRs, gate-turn-off thyristor requiring large duration trigger pulses.