The Wireless TV Headphone circuit is basically a simple FM transmitter. Its function is to convert audio signals available from TV equipment to FM signals. The audio signals must be amplified and then their modulated for transmission as FM signals. Acting as audio preamplifier, transistor BC547 amplifies input audio signals obtained at jack J1 from the TV. Gain adjustment is provided by a preset VR1. Other passive components like resistors and capacitors provide proper biasing for the transistor. 
The transmitted frequency is in the range of 88-108 MHz which comprises the FM band, The desired frequency can be obtained by varying the trimmer capacitor which is connected in parallel to an inductor.

Most Television sets nowadays come equipped with audio out RCA sockets to which headphones can be connected. This is particularly useful when one wants to watch television without disturbing others with the loud audio. Most wired headphones require the viewer to be seated only 10 meter away from the TV screen which can prove to be inconvenient. The Wireless TV Headphone circuit is a low-cost solution which converts the TV audio output to FM signals. Hence, one can watch their favorite TV program without disturbing others by simply using a portable FM receiver headphone.

Download the pdf here.