Audio Amplifier 1W

This compact circuit delivers approximately 1 watt of audio output power from a 9V supply, making it suitable for small speakers or portable audio applications.

The design uses a two-stage transistor amplifier, where Q2 serves as the output stage and should be mounted on a heatsink to dissipate excess heat during operation.

The R2 resistor controls the bias and gain characteristics — it must be selected to achieve minimum quiescent current while maintaining maximum voltage gain. In most cases, R2 falls between 22Ω and 100Ω.

While the overall gain is modest, the circuit offers good audio clarity and low distortion, making it ideal for:

• Small radio or intercom systems
• Educational amplifier experiments
• Battery-powered devices requiring a simple 1W output stage