Common base amplifier pdf
The common base amplifier uses a bypass capacitor – or a direct connection from base to ground to hold the base at ground for the signal only! The common emitter amplifier (except for intentional R E feedback) holds the emitter at signal ground, while the common collector circuit does the same for the collector. The Common-Base Ampliﬁer Basic Circuit Fig. 1 shows the circuit diagram of a single stage common-base ampliﬁer. The object is to solve for the small-signal voltage gain, . In other words, the common base amplifier attenuates the electric current rather than amplifying it. The base-emitter junction J E at input side acts as a forward biased diode. So the common base amplifier has a low input impedance (low opposition to incoming current).