Introduction of Ampliciers

AMPLIFIERS

INTRODUCTION

An amplifier is defined as the device which increases the magnitude of the input signal and produces a larger electrical output. The amplifier needs a source of energy for amplification from battery or de source and filter combination.

The amplifier also has atleast one active device such as BJT, FET or electron tube. This active device converts the energy from the dc source into the energy at the output of amplifier.

TYPES OF AMPLIFIERS

If the output signal is directly proportional to the corresponding input signal, then the amplifier is called linear amplifier.

If the output signal is not directly proportional to the input signal, then the amplifier is called non-linear amplifier.

Linear amplifiers are further classified depending upon the mode of operation i.e., the way in which the amplifiers operate on the predetermined set of values.

Now let us discuss the operation of small signal amplifiers and analyze its performance.

SMALL SIGNAL AMPLIFIERS

Small signal indicates that the input signal is very small in the range of few mV. The amplifier which operates on small signal is called small signal amplifier.

As the input signal is small, the transistor will operate in the linear region of its transfer characteristics. So, it is called linear amplifier. The output signal will not have any distortion.

Example: CE, CB and CC amplifier.