Ujt Relaxation Oscillator Circuit Diagram. When the supply voltage vbb is applied the capacitor c starts charging. The schematic below exhibits the fundamental ujt relaxation oscillator circuit working with a type 2n2646 ujt device.
R1 and r2 are current limiting resistors. Resistor r and capacitor c sets the frequency of the oscillator. The ujt relaxation oscillator circuit is a non linear oscillator used to generate a nonsinusoidal repetitive output signals that can trigger power control devices such as scrs and triacs the ujt acronim comes from.
Resistors r1 and r2 set the peak voltage vp and intrinsic standoff ratio η of the put.
After finishing this experiment students are able to understand the operation of ujt as a relaxation oscillator. When the supply voltage vbb is applied the capacitor c starts charging. Here the components rt and ct work like the timing elements and determine the frequency or the oscillation rate of the ujt circuit. The output is actually somewhat curved sawtooth wave consisting of peak amplitude roughly corresponding to the supply voltage which is 22 5 v here.
