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30 Watts Audio Amplifier Schematic Circuit Diagram


A 30-watts audio amplifier circuit using TDA2040 is shown here. TDA2040 is a Class AB monolithic integrated audio amplifier available in the Pentawatt package. The IC has low harmonic distortion, a low cross-over distortion, and built-in circuitry for short-circuit protection.

In the circuit, two TDA2040 ICs are wired in BTL (Bridge Tied Load) configuration in order to deliver 30W output into an 8-ohm speaker at +/-16V DC supply. Capacitor C1 is the input DC decoupling capacitor. The network comprising components R2, C4, and R3 provides feedback for IC1 while R7, C6, and R8 networks provide feedback for IC2. Network C5, R5, and C9, R9 provide high-frequency stability. Capacitors C2, and C3 filter the positive supply rail while capacitors C7, and C8 filter the negative supply rail.

30 Watts Audio amplifier circuit diagram

30 Watts Audio Amplifier Schematic Circuit Diagram


  • A well-designed and good-quality PCB will always improve sound quality.
  • Use +/-16V DC dual supply for powering the amplifier.
  • Heat sinks are necessary for IC1 and IC2.
  • The load can be an 8-ohm speaker.
  • C2 and C7 must be rated 25V and other electrolytes can be 10 or 15V.
  • This amplifier’s setup must be done properly and without haste
  • Connect the Power Supply Unit (separately tested) to the Power Amplifier but not the Preamp: the Power Amplifier’s input must be left open.

The TDA2040 is a monolithic integrated circuit in a Pentawatt  package, intended for use as an audio class AB amplifier. Typically it provides 22W output power (d = 0.5%) at Vs = 32V/4Ω . The TDA2040 provides high output current and has very low harmonic and cross-over distortion. Further, the device incorporates a patented short circuit protection system comprising an arrangement for automatically limiting the dissipated power so as to keep the working point of the output transistors within their safe operating area. A thermal shut-down system is also included.


  • Wide-range supply voltage, up to 40 V
  • Single or split power supply
  • Short-circuit protection to ground
  • Thermal shutdown
  • PO = 25 W @ THD = 0.5%, VS = ±17 V, RL= 4 Ω
  • PO = 30 W @ THD =10%, VS = ±17 V, RL = 4 Ω

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