Learning Electronics

Learning Electronics

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Laptop Audio-Out Splitter Circuit Diagram

Why share a single earphone pair with your friend while watching a dVd on your laptop?

This active splitter for laptop audio-out is powered from a USB and provides individual channel gain of 39 dB and individual volume control of a head-phone channel. The circuit uses two TDA2822M audio power amplifier ICs for head-phones/small speakers. Each 8-pin DIP TDA2822M has two audio power amplifiers: one to serve the left channel, and the other for the right channel (stereo). Therefore to get a two-headphone output, you require four amplifiers or two pieces of TDA2822M. This laptop audio-out splitter boosts the bass. However, it introduces a slight hiss (noise), which actually improves the listening experience, and is susceptible to interference from mobile phones.

Screenshoots of the project:
 Laptop Audio-Out Splitter In A Plastic Box
Laptop Audio-Out Splitter In A Plastic Box
 Laptop Audio-Out Splitter Circuit
Laptop Audio-Out Splitter Circuit - Perf Board
 Laptop Audio-Out Splitter's Jacks connected to Laptop
Laptop Audio-Out Splitter's Jacks connected to Laptop

Circuit diagram:
 Laptop Audio Splitter Schematic Circuit Diagram
Laptop Audi-Out Splitter Circuit Diagram


P1 = 47K
P2 = 47K
R1 = 4.7R
R2 = 4.7R
C1 = 100uF-25V
C2 = 100uF-25V
C3 = 470uF-25V
C4 = 470uF-25V
C5 = 100nF-63V
C6 = 100nF-63V
C7 = 10uF-25V

IC1,IC2= TDA2822M
J1,J20 = Audio InPut Socket


The TDA2822M is a remarkable IC with a low external component count. While the LM386 is capable of providing an unnecessarily larger gain than this IC, the TDA2822M wins on three counts: simplicity, low noise and two power amplifiers in one 8-pin pack-age. The TDA2822M can operate over a voltage range of 1.8V to 15V. The USB port provides 5V and 100mA current, which is more than enough for two pairs of headphones. Left output of Laptop will be connected to Left input of both amplifier circuits and the right channel will be treated same to right channel. Pictures of this project are shown below.