An Amplifier is an electronic circuit or device which is used for amplification purpose and used mainly in sound reproduction as well in our electronic industry widely. There are many types of amplifier available by using different components like transistor based amplifier, op-amp based amplifier, transformer based amplifier. Sometimes we use a Preamp Circuit in circuits for pre-amplification of weak signal when the audio source sound level is too low. Pre-amlification of low level signals is necessary before feeding them into a power source, for clear and noiseless sound. In this project, we will build a Simple Preamplifier Circuit using NPN transistor BC547.

Here we have used this Preamplifier circuit for amplifying the AUX output of Mobile phone and amplifying the voice input given by the condensor mic or microphone.