Power amplifier board with NS8002 (beyond the domestic 8002A, B, C, D) AB class efficient power amplifier chip carefully debug sound quality perfect, strong power, without any interference, it is fine PCB size: length 16 width 10.5 thickness 2.6mm (with protruding part);Installation: SMT patch;Output power: mono 3W;Supply voltage: 2V-5V (3.7V lithium battery can be used);Output impedance: 4-8;Frequency response: 150HZ-20KHZ;Efficiency: 90%;Mute control: Yes;Volume adjustment: none;Wiring instructions:This board should be grounded, 3 feet for the power supply negative and ground sharing. 1 foot for the quiet output, and 3 feet to be connected together, when the voltage is 0 when the sound, the voltage is 0.5-5V when the silent, no sound output.Package Included:1 x Mini Amplifier Board