The Grounded-Emitter Amplifier

Author: N.H. Crowhurst

Grounded-emitter amplifier with no load: A small current and voltage change in the base circuit produces a much larger current change in the collector circuit.

Grounded-emitter amplifier with added load resitor RL: A small current and voltage change in the base circuit produces a much larger voltage and current change in the collector circuit.

By turning the circuit around to what is called grounded-emltter connection, the input is applied to the base. Only a small proportion of the emitter current flows through the base connection. With a transistor, the current applied to the base is more important than the voltage. Because of the small size of the base current compared to the collector current, this circuit can be regarded as providing current amplification. In addition, voltage amplification can be obtained by using a resistor in the collector circuit.