Difference Between Diode And Transistor. While thyristor has 2 terminals and operates as a switch. Whereas due to 4 layers, the thyristor has 3 junctions.

Key differences between photodiode and phototransistor a photodiode consists of a semiconductor diode, that generates current when exposed to light. Typically 0 to 7 volts at 10 ma will make diodes very useful. And transistors are used amplification and switching related issues.