采用LM386制作的微小音频放大器电路

The Tiny Audio Amplifier kit is a good choice for battery operation.  It is based on LM386 IC.
 
Power supply - 6 - 12 VDC

Output power - 1 W, 8 Ohm

The quiescent power drain is only 24 mW when operating from 6 VDC

Self-centering output quiescent voltage

Onboard PRESET to adjust volume

Terminal pins for connecting power supply, audio signal and speaker

Power-On LED indicator

ON/OFF PCB mounted slide switch for power supply

Four mounting holes of 3.2 mm each

PCB dimensions 44 mm x 44 mm

Parts List

Inputs - Outputs configuration
 

pcb