This automotive circuit was found in the September 1992 issue of Radio Electronics magazine. The circuit directly drives a relay that must have a coil resistance greater than 65 ohms.
Found in a 1963 documentation, this circuit employs germanium transistors of the time. Transformer and...
In the figure we have a way of receiving ultrasonic signals of a single frequency using a PLL 567....
This traditional circuit generates a 200 Hz sinusoidal signal. The frequency depends on the...