SOLUTION

Common-Collector Configuration

In a common-collector configuration, the collector terminal of a transistor is connected as a common terminal between input and output as shown in fig. The base and collector terminals are used to apply the input signal whereas the output signal is obtained. The CC configuration is also commonly known as the emitter follower or the voltage follower. This is because the output signal across the emitter is almost the replica of the input signal with little loss. In other words, there is no phase inversion between input and output in the emitter follower circuit. The output voltage is in phase with the input voltage and hence the voltage gain will be a maximum of one. The common-collector configuration is used primarily for impedance-matching purposes since it has a high input impedance and low output impedance, opposite to that of the common-base and common-emitter configuration.