A transistor can act as a switch with two main states:

• ON (Saturation): The transistor allows current to flow, behaving like a closed switch.

• OFF (Cutoff): The transistor blocks current, behaving like an open switch.

In saturation mode, the transistor is fully on, and in cutoff mode, it is off. A small base current controls whether the transistor is on or off.

Significance
Transistors as switches are essential in digital circuits, logic gates, and power control applications.