What is an amplifier?

            An amplifier is a device used to increase or strengthen the power of a signal. They can be seen in audio equipment of all kinds.

            Let’s take the example of a hearing aid. It has a microphone that picks up sounds from all around and converts them to electric signals that constantly changes in strength. Here, an amplifier takes the signals, and boosts it many times before feeding it into the tiny loudspeaker placed inside the ear canal. The sound thus produced is ‘amplified’ before it reaches the person. That means, the duty of the amplifier is to convert a small electric current into a larger one.

     

 

            Depending on their functions, amplifiers can be categorized as weak-signal amplifiers or power amplifiers. The former is designed to deal with exceedingly small input signals. They are used in audio tape players, CD players tec. History notes that the first electronic device that could amplify was the triode vacuum tube, invented by Lee De Forest in 1906.