The ETB-243 PUT Characteristics & Relaxation Oscillator Trainer is designed to study the static and dynamic characteristics of a Programmable Unijunction Transistor (PUT) and its application in a relaxation oscillator circuit. This model enables students to understand the triggering and switching behavior of PUTs and observe waveform generation in relaxation oscillator configurations. It is integrated with a regulated power supply, in-built test points, and clear circuit layout for easy experimentation—ideal for analog electronics and semiconductor device courses.