
The emitter current I E increases with the small increase in emitter-base voltage V EB.The emitter and collector current is independent of the collector base voltage V CB. The junction behaves like a better diode. When the value of the voltage base current increases the value of emitter current increases slightly.The PN emitter junction is forward biased. For a specific value of V CB, the curve is a diode characteristic in the forward region.The following points are taken into consideration from the characteristic curve. The input characteristic curve is shown in the figure below. The curve plotted between emitter current I E and the emitter-base voltage V EB at constant collector base voltage V CB is called input characteristic curve.

The input and output characteristic curve of the potentiometer explains below in details. The value of collector voltage changes slightly by changing the value of the potentiometer R 2. The value of the emitter change to a large value even the value of a potentiometer slightly change. A series resistor R S is inserted in the emitter circuit to limit the emitter current I E.

The emitter to base voltage V EB can be varied by adjusting the potentiometer R 1. The characteristic diagram of determining the common base characteristic is shown in the figure below. Characteristics of Common Base (CB) Configuration The leakage current is also abbreviated as I CO i.e., the collector current with emitter circuit open.

This leakage current is represented by as I CBO, i.e., collector-base current with emitter circuit is open. The above expression shows that if I E = 0 (when the emitter circuit is open) then still a small current flow in the collector circuit called leakage current. The minority charge carrier is because of the flow of minority charge carrier across the collector-base junction as the junction is heavily reversed.

