A major application of transistors is their use as switching devices in computers and other control applications. In this experiment the transistor is used as an inverting switch that is the transistor output is at logic-high level for a logic-low input applied at its base terminal and the output is at logic-low level for a logic-high input. When a logic-low input is applied, the transistor is in the cut-off region and acts as an open switch. It is in the saturation region for a logic-high input and acts as a closed switch. While designing the transistor-based switch, you should ensure that the transistor is heavily saturated for a logic-high input signal.