This is the receiver for the previous transmitter. The signal consists of digital pulses with a compatible TTL or CMOS output. The integrated circuit is a 4093 and a photodiode of any type.
This circuit was found in 2003 documentation, but all components used are still current. The alarm...
Active with the output at the high level, this oscillator was found in November 1984 Radio...
This circuit, from a 1976 documentation, amplifies signals from 100 Hz to 600 kHz with a voltage fan...