The commonly used coupling methods are R.C. coupled Transformer-coupled Direct-coupled

The bypass capacitor at the emitter offers a low reactance path to the signal. As it allows more flow of the signal than the normal circuit path.

The ratio of output voltage \(V_O\) to the input voltage \(V_S\) is known as the amplification or voltage gain of the amplifier. Also called the loop gain, denoted as \(A_V=\frac{V_O}{V_S}\)

Cascading means the output of the first stage is connected to the input of the second stage through a suitable coupling device and so on. The coupling devices are generally capacitors, transformers, etc.

The bandwidth of an RC coupled amplifier lies between 50 Hz to 20kHz.