PUT: Programmable Uni junction Transistor
It is a part of the Thyristor family and has three terminals,
- Cathode (K)
- Anode(A)
- Gate(G).
The reason it is known as programmable is that the peak voltage, charging - discharging time of capacitor, etc can be programmed/controlled by using external two resistors.
SCR: Silicon Controlled Rectifier
As the name says, the thyristor is made up of silicon, and rectifier illustrates that if the SCR is subjected to an Alternating Cycle (Sinusoidal Wave), it will conduct only in the positive half cycle in the presence of the Gate signal, which triggers the SCR. In the absence of the Gtae signal, the SCR will not conduct as it keeps the junctions J1 and J3 reverse biased and only junction J2 will be forward biased.
On the application of gate signal the junction J3 is forward biased and helps conduction, giving a heavy increase in charge carriers, which increases the current.
This is the reason why, Thyristors are included in High Power Switching families.
Circuit Diagram:
Figure 1: Final circuit Diagram
The demonstration video link: https://youtu.be/x36ljk17ZHo
