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20W audio amplifier using TDA7240 Schematic Circuit Diagram

The audio amplifier shown here is based on the TDA7240 IC from ST Microelectronics. The TDA 7240 is an integrated audio amplifier IC that can deliver 20 watts of audio output power into a 4ohm load. The IC has a minimum external parts count and is available in the 7-pin compact Heptawatt package. The IC also has a lot of good features like loudspeaker protection, short circuit protection, low noise, low distortion, etc. The circuit can be operated from a 12V DC single power supply and this makes it very useful in car audio applications.

Circuit diagram

20W audio amplifier using TDA7240 Schematic Circuit Diagram


  • Assemble the circuit on a good quality PCB.
  • Use 12V DC for powering the circuit.
  • K1 can be a 4 ohm, 20W speaker.
  • S1 is the standby switch and S2 is the ON/OFF switch.
  • LED D2 is a power-ON indicator.
  • Fit the IC to a proper heatsink.

About TDA7240A:

The TDA7240A is a 20-watt bridge audio amplifier IC made specifically for automobile radios. The TDA7240A takes up little space on the printed circuit board because of its low external component count and tiny Heptawatt 7-pin power package.

A complete set of on-chip protective measures ensures dependable operation. Protection against AC and DC output short circuits (to the ground and across the load), load dump transients, and junction overheating are among these features. When one of the outputs is short-circuited to the ground, the TDA7240A safeguards the loudspeaker.


There are various usages of audio amplifiers. Some of them are listed as follows:

  1. In sound systems, these amplifiers are the most widely used.
  2. In various instruments that relate to music, these amplifiers are installed.
  3. In radio signal broadcasting these amplifiers are used.
  4. The signal transmission for long-distance communication is the most amplifier that is utilized.
  5. For the wireless transmission of the signals, audio amplification is required.
  6. Classification of the amplifier can be done in 3 different ways. Voltage amplifiers. Current amplifiers. Power amplifiers.

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