Introduction to amplifier. Working construction theory conclusion.

Circuit Explanation

A single stage common emitter RC coupled amplifier is a simple and elementary amplifier circuit. The main purpose of this circuit is pre-amplification that is to make weak signals to be stronger enough for further amplification. If designed properly, this RC coupled amplifier can provide excellent signal characteristics.

The capacitor Cin at the input acts as a filter which is used to block the DC voltage and allow only AC voltage to the transistor. If any external DC voltage reaches the base of the transistor, it will alter the biasing conditions and affects the performance of the amplifier.

R1 and R2 resistors are used for providing proper biasing to the bipolar transistor. R1 and R2 form a biasing network which provides necessary base voltage to drive the transistor in active region.

The region between cut off and saturation region is known as active region. The region where the bipolar transistor operation is completely switched off is known as cut off region and the region where the transistor is completely switched on is known as saturation region.

Resistors Rc and Re are used to drop voltage of Vcc. Resistor Rc are a collector resistor and Re is emitter resistor. Both are selected in such a way that both should drop Vcc voltage by 50% in the above circuit. The emitter capacitor Ce and emitter resistor Re makes a negative feedback for making the circuit operation more stable.