Circuit Wiring

Audio input from PL1 frequency modulates the VCO section of a 4046 PLL chip. The VCO output drives Q1, a switching transistor. Q1 drives two IR LEDs. The signal produced is around 100 kHz, FM carrier VCO sensitivity is around 7.5 kHz/V.

Wireless IR Headphone Transmitter Circuit Schematic

This is a stereo earphone amplifier circuit of using LM4910 IC. This circuit is very straightforward so it is very cool to comprise even in support of beginners after. for the reason that the voltage source is used solitary 3 VDC you can utilization 2 x A3 battery trendy progression stacking.

LM4910 Boomer belonging to the series of state Semiconductors is an integrated stereo amplifier is primarily intended representing earphone stereo applications. The IC can come about operated from 3.3V ans its 0.35mW can release output power into a 32 ohm load. The LM4910 has very low distortion (minus than 1%) and the shutdown current is less than 1uA. This low shutdown current makes it as it should be designed for battery operated applications.

C1 and C2 are the input DC decoupling capacitors for the gone and due input channels. R1 and R2 are the respective input resistors. R3 is the feed back resistor representing not here channel while R4 is the feed back resistor for the right channel. C3 is the power supply filter capacitor. The criticism resistors as well sets the blocked ring expansion voguish conjunction with the corresponding input resistors.