This circuit lets through the 300 Hz to 3kHz range that corresponds to the human voice. We found it in the Radio Electronics magazine of February 1990. The circuit uses both parts of the LM381.
This circuit was found in the April 1983 issue of Radio Electronics magazine. Its purpose is to...
Evidently, this is a project that still needs some improvements. For example, the ignition can be...
This very low voltage regulator for 3 V input (2 batteries) was obtained in a documentation from...