In this configuration, the input is supplied to the emitter-base junction and output is taken from the collector-base junction. The emitter-base junction is forward biased and collector-base junction is reverse biased. Voltage amplification in this circuit is possible by reason of relative input and output circuitry rather than the current gain (?) which is always less than unity. The input circuit has low resistance whereas output circuit has very large resistance. Although changes in the input and output currents are same, the a.c. drop across output resistance is large. Hence changes in VCB¬ (which is the output voltage) are much larger than changes in the input a.c. signal. One of the uses of a CB amplifier is in matching a low-impedance circuit to a high-impedance circuit.