Tuesday, November 1, 2011

Class-AB Headphone Amplifier Circuit

This is the circuit diagram of Class-AB headphone amplifier which built using 3 transistors of BC549 and BC559. The circuit is very simple and will give you good audio performance.

The power consumption of this headphone amplifier circuit is claimed to be very low. Two pieces of AA battery will supply the circuit for long time.
Class-AB Headphone Amplifier circuit diagram

Components List:
R1 - 100K
R2 - 330
R3 - 100
R4 - 22 (2 - 4.5V)
R4 - 100 (5 - 12V)
C1 - 4.7uF
C2 - 4.7uFC3 - 100 - 1000uF
C4 - 220uF
P1 - 100K
D1, D2 - 1N4148
Q1, Q2 - BC549
Q3 - BC559

Power Supply Voltage: 2 - 12V
Power Consumption: 10mA/3V - 30mA/12V (measurements taken using a stereo version)
Output Power: 300mW

The circuit can be used for common electronic devices such as radios, CD/DVD Players, computers, audio/video players, ipods etc.

Circuit Source: Class-AB Headphone Amplifier Circuit

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 wikipedia.org

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:

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