Patent ID: 8897468

Claim:
A noise control circuit, comprising: a filter that receives audio signals and obtains a noise signal portion of the received audio signals; a rectifier that converts the noise signal portion into a current signal; an amplifying circuit comprising an amplifier, the amplifier comprising an inverting input terminal, a non-inverting input terminal, and an amplifying output terminal, the inverting input terminal being connected to the rectifier, the non-inverting input terminal being grounded; a switch that controls output of the audio signals according to intensity of the current signal; and an adjusting circuit comprising a variable resistor, the variable resistor comprising two connecting terminals and an adjusting terminal, one of the connecting terminals being connected to the amplifying output terminal, another connecting terminal being grounded, and the adjusting terminal being connected to the switch; wherein the amplifying circuit further includes a first resistor, a second resistor and an adjusting resistor; the inverting input terminal is connected to the rectifier by the first resistor, the non-inverting input terminal is grounded by the second resistor, the adjusting resistor is set between the inverting input terminal and the amplifying output terminal.