A transistor connected in common base configuration has
Right Answer is:
Low Input resistance and high output resistance
SOLUTION
In this circuit configuration of a transistor, the base terminal is used as a common terminal between input and output as depicted in Fig. The input signal is applied between the emitter and base terminals. The output will be taken from the collects and base terminals. To explain the operation of NPN and PNP transistors, the common base configuration is used.
Characteristic of common base (CB)
There are two important characteristics of CE
(1) input characteristics.
(2) Output characteristics.
Input Characteristic. It is the curve between base current IB and emitter-base voltage VBE at constant collector-base voltage VCB.
The emitter current IE increases rapidly with a small increase in emitter-baa voltage VEB which means that input resistance is very small.
In fact, the input resistance is the opposition offered to the signal current. As a very small VEB is sufficient to produce a large flow of emitter current, therefore, the input resistance is quite small, of the order of a few ohms.
Output Characteristic. It is the curve between collector current Ic and collector-base voltage VCB at constant emitter current IE. A very large change in collector-base voltage produces only a tiny change in collector current. This means that output resistance is very high.