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Infrared wireless headphones circuit

Published on Dec 23 2010 // Telephone Communication Circuits

Infrared wireless headphones circuit .

Since induction of the headset transmitter circuit must be permanently installed in the room wall or ceiling, it can not be used outdoors, this is inductive main drawback of wireless headphones. The infrared wireless headphones are not, because of its signal transmission in a compact infrared transmitter circuit, both in the room for electronic teaching, home television and stereo equipment, audio wireless receiver, but also in outdoor use of portable tape recorders, CD, VCD and MP3, easy to remove the headphones, to achieve true wireless "Walkman."
Infrared wireless headphones transmitter circuit shown in Figure (a) below. Insert the plug when using XP TV, radio cassette player’s headphone jack, the audio signal by the capacitor Cl coupled through XP, transistors VTl amplification, then the infrared emitting diodes VD2 out VDl and contains audio radio emission infra-red. After installation into the circuit will adjust the bias resistor R2, so that flow through VDl and VD2 can l0mA quiescent current.
Figure (b) for the infrared wireless headphones receiver circuit. VD3 ~ VD5 infrared receiver to the transmitter receiver circuit for infrared signal, to convert it to audio signals, and then amplified by the transistor VT2 ICl into an integrated operational amplifier for power amplification, the final output from the headphone BE. Circuit using three infrared receiver to receive signals to be comprehensive. Debugging, the first hand-to-cathode tube infrared receiver, adjust the resistance of R4, R5 BE headphone output to the loudest hum, and then connected to firing circuit, the appropriate adjustments the volume of the TV or radio cassette recorders the size of the headset until the outgoing loud and clear so far.