This project can be developed for those who need to establish connection between television and headphones without using wire, but using infrared light. The infrared light is used to transmit audio signals from the television to your headphones. This circuit could cover up to 6 meters. If lenses and reflectors with IR sensors is used, the range can be extended.
To drive the two series-connected IR LEDs, the infrared transmitter uses two-stages transistors. An audio output transformer is used in reverse to couple the audio output from the television to infrared transmitter. The transistors T1 and T2 amplify the audio signals received from the television via audio transformer. Low-impedance output windings which uses lower gauge or thicker wires are used for connection to TV side while high-impedance windings are connected to the infrared transmitter. The Red LED1 functions as a zener diode (0.65V) as well as indicator for supply-end. It uses power a 9V mains adapter or battery.
The infrared receiver uses 3-stage transistor amplifier. Both T4 and T5 form audio signal amplifier. T6 is used to drive the headphone. For maximum clarity, the potentiometer VR2 can also be adjusted. For portable operation, a 9-volt battery can be used.