Transistor as an Amplifier

 

Transistor as an Amplifier Working 

Very small current flows between a transistor's emitter and base when its base receives a small input signal. This low current then stimulates the flow of a much larger current between the emitter and collector, amplifying the input signal.

The amount of bias current given to the base of a transistor controls how much amplification it can produce. Bias current is the flow of current across a transistor's base-emitter junction when there is no input signal. The quantity of bias current establishes the transistor's operating point and the maximum output signal that can be generated. Depending on the sort of circuit layout employed, the transistor can be utilized as a voltage amplifier or a current amplifier. In a typical emitter setup, the base receives the input signal while the collector receives the output signal. The transistor functions as a voltage amplifier in this design, amplifying the input signal voltage to a higher output signal value.

Fig4: Transistor Amplifier circuit 

In a common collector arrangement, the base receives the input signal while the emitter receives the output signal. The transistor functions as a current amplifier in this form, amplifying the input signal current to increase the output signal current.

Generally, the fundamental idea behind transistor amplification is the use of a small input signal to regulate a larger output signal; this is accomplished by the right biassing of the transistor and circuit design.