This polarity inverter circuit for voltages down to about -12 V was found in the December 1992 issue of Radio Electronics magazine. The current is a few mA.
The sensor of this circuit, from an old documentation, is nothing more than an electret...
Found in a magazine from the '90s, this circuit uses an integrated circuit from the era that is...
This low power amplifier, with 2 W in charge of 16 ohms, was found in a Japanese magazine from the...