The basic construction of single stage CE (common emitter) amplifier is shown in above circuit diagram. The potential divider biasing is provided by the resistors R1, R2, and R3.it provides good stabilization of the operating point. The capacitors Cc1 and Cc2 are called as the coupling capacitors used to block the AC voltage signals at the input and the output sides. The capacitors CE works as a bypass capacitor. It bypasses all the AC current from the emitter to the ground and avoids the negative current feedback. It increases the output AC voltage. The resistance R0 represent the resistance of whatever is connected at the output. It may be load resistance or input resistance of the next stage.