Found in a September 1972 Radio Electronics magazine, this circuit uses RCA's CA3020, a multi-purpose amplifier in a round metal 12-pin package.
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...