This is a circuit for receiving signals from the previous transmitter. The circuit uses a common phototransistor. It was found in the August 1984 issue of Radio Electronics magazine.
August 2017 - Mouser Electronics is announcing the availability of TDK ICS-52000 microphones with...
This circuit, which can be used as a shield or in other applications, can be found elsewhere on...
This crystal or galena radio was found in documentation from the 1990s. The earpiece must be a...