Common Collector Amplifier Circuit

From above circuit, D.C. biasing is provided by R₁, R₂ and R_E. The load resistance is capacitor coupled to the emitter terminal of the transistor. When a signal is applied to base of the transistor, V_B is increased and decreased as the signal goes positive and negative respectively.

From figure, V_E = V_B - V_BE

Consider V_BE is constant, so the variation in V_B appears at emitter and emitter voltage V_E will vary same as base voltage V_B. In common collector circuit, emitter terminal follows the signal voltage applied to the base. It is also known as emitter follower.