Found in an Electronic Design and 1970s, this circuit uses transistors of the time. The transistors can be replaced with equivalents and the relay is 12 V depending on the power supply.
This circuit was obtained in an old publication. The FET can also be the BF245. The potentiometers can be...
This circuit is from a Radio Electronics magazine from August 1990. The circuit uses components from the...
This circuit shows on the screen of an oscilloscope two signals alternately at a frequency that depends...