Thursday, May 24, 2012

Simple Pre-Amp with One Transistor

Simple Pre-Amplifier circuit with One Transistor

This is a very simple pre-amp circuit which use a transistor as a active component to boost the input signal. Its simplicity makes this circuit easy to built and inexpensive. The microphone used in this circuit is electret type which is very sensitive detecting the sound around its.

It require 3-9V DC power supply with small power consumption.

About Audio Amplifier
An audio amplifier is an electronic amplifier that amplifies low-power audio signals (signals composed primarily of frequencies between 20 - 20 000 Hz, the human range of hearing) to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain.

The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification, equalization, tone control, mixing/effects, or audio sources like record players, CD players, and cassette players. Most audio amplifiers require these low-level inputs to adhere to line levels.

While the input signal to an audio amplifier may measure only a few hundred microwatts, its output may be tens, hundreds, or thousands of watts. More explanation about power audio amplifier can be found at

This is a video tutorial about how to a very simple audio amplifier based on the LM386 amplifier chip. It can be built for less than $20 (or might be less than $8 in some countries) and used to amplify any low level audio signal including a guitar, bass or mp3 player.

Watch the video:

No comments: