This tone recognizer circuit that relies on R5 and C1 was found in the December 1994 issue of Electronics Now. The circuit operates on voltages from 6 to 12 V typically.
Using Linear Technology's LTC4252-1, this circuit was found in a 2005 manual. The circuit makes use of...
Mouser Electronics is providing integrated circuits DRV8885 from Texas Instruments consisting of...
This circuit is from an 80's documentation. It makes use of two SCRs with current capacity...