Circuitry using infra-red (IR) diodes in remote control units. In one
embodiment an IR LED is used both as a transmitter diode and also as a
receiver diode responsive to light to thereby develop photocurrents and/or
voltages for use by external circuitry. In a second embodiment an improved
amplifier circuit is provided for an IR LED and IR photo detector diode
which is mounted behind, and receives light through, the transmitter IR
LED.
