infra-red receiver

This IR receiver can be used with the complementary transmitter described elsewhere in this issue. The IR signal is received by photodiode D 1. This diode is reverse-biased (its bias voltage being decoupled from noise on the supply line by R4, RS, CS and C6) and its leakage current varies with changes in incident light. To enable the receiver to be sensitive without being interference-prone it must be made selective, so a tuned circuit LI/Cl is included.