We found this circuit in the January 1978 issue of Radio Electronics magazine. The integrated circuit is from that time and is powered by a 9 V battery. The signal must be applied to an amplifier.
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...