A four-layer transistor called a thyristor is frequently used for managing a lot of electricity. A thyristor can be switched on or off, but it can also manage electricity through a process known as phase angle control. As a result, the current input's orientation can be changed to regulate the quantity of power production. A lamp's dimming button is an illustration of this.

Thyristors can handle high power levels and use phase angle control, but they are not as well suited for low power uses. This is so that they can only be switched off by changing the current's path. A thyristor may take longer to switch on or off than other transistors because of this. Thyristors are also inefficient for uses where current must flow to and from each component because they can only transmit in one way.