Current Amplification Factor:

There are two current amplification factors, the alpha factor (α) and the beta factor (β) defined below :

The alpha factor (α) is also called the current amplification factor and is the ratio of change in collector current (I_C) to change in emitter current (I_E).

In general,

The beta factor (β) is the current gain factor (also called the transport factor) of a common emitter circuit and is defined as the ratio of change in collector current (I_C) to change in base current (I_B).

In general,