Using a 4046 PLL we found this circuit in the December 1989 issue of Radio Electronics magazine. The circuit operates at 220kHz, but this frequency can be changed by changing C3.
This is a typical symmetrical power supply configuration. The transformer voltage determines the...
This circuit turns on your car's backlight when a vehicle coming from behind gets too close to it...
This circuit was found in Popular Electronics from 1969. The circuit uses a small speaker as a...