What Is a Unijunction Transistor?
A unijunction transistor (UJT) is a simple semiconductor device with three terminals, distinguished by its effectiveness as a voltage-controlled switch operating at low voltages.
Its design lends itself to use in oscillators, timers, sensors, and control circuits, where precise timing and switching are essential. The UJT is particularly valued in applications requiring stable oscillation frequencies and reliable switching, including oscillating and timing circuits.
The UJT operates on the principle that an applied voltage between the emitter and the base leads to a rapid increase in the emitter current. This characteristic makes it suitable for generating fixed-frequency oscillations through a resistor-capacitor network and acting as a pulse-triggered switch in various applications.