B.J.T as Voltage Amplifier

B.J.T as Voltage Amplifier

If a weak electrical signal is provided between the two input terminals of the transistor, then it amplifies the strength of the transistor, then it amplifies the strength of the signal. Thus an amplified signal is obtained across two output terminals of transistor. This process is known as amplification.

Thus, amplification is a process in which amplitude of an electrical signal over output of transistor is increased in linear style. However,diagram of output waveform is similar to diagram of input waveform. Only the amplitude of input signal is changed on reaching output.

Since the voltage amplification depends upon output resistance (its value is very low), so the value of output voltage is very high as compared to the value of input voltage. This should be kept in mind that when a transistor is to be used as amplifier, then it should be biased in its active or linear region.

There are three terminals of a transistor. Its one terminal is used for input, second for output, while third works as grouped, which is common for input & output terminals.

When a transistor is to be used as an amplifier, then it is connected in one of these three configurations.

                  i.        Common-Base Amplifier

                ii.        Common-Emitter Amplifier

               iii.        Common-Collector Amplifier