CBSE Class 12-science Answered

Let me tell the physical inetrperation behind the transistor being able to act as amplifier.

Refer tothe output cahractreistics of Common emitterTransister as givne in ur NCERT book.

The graph between Voltage Vce and Collector current being plotted at different base current I_b.

Here we see that for a given Vce, if the input current Ib in the input circuit is incaresed through few micro amperes, there is seen a change in output current Ic in the output circuit in the order of few milliampres!

This is the principle behind the Common emitter being used as amplifier.

When a small ac signal of varying voltage is applied to the input circuit, we obtain a much higher variation in the output current at the output circuit.

For the reamining equations and all, pls refer to your NCERT book.

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