This circuit was found in the August 1992 issue of Radio Electronics magazine. The circuit can be used as an isolated shield for microcontrollers.
This old oscillator using germanium transistors has a high impedance headphone as inductor to...
This old fashioned amplifier can source some watts to a low impedance loudspeaker. The circuit...
This 50 Hz rejector or notch filter was found in a 1975 documentation. Other frequencies can be...