This circuit was obtained in the 1990 Motorola Linear Databook. The circuit uses a 139 series comparator, but other series can be used. The power source need not be symmetric.
The figure shows how to use a varicap in a conventional tuning circuit. The circuit may be an...
We found this circuit in the January 1992 issue of Radio Electronics magazine. The circuit...
This filters blocks radio interference or noise coming from the AC Power line. Noise such as the...