Found in a 1980s documentation, this amplifier uses an integrated circuit that is not easy to obtain now as it is of the era. The circuit is intended for FI ceramic filter circuits.
This circuit, obtained in an old publication, causes a second telephone bell to be played in a...
The tone produced by this circuit depends on the capacitor and the adjustment of the...
This circuit uses two sensors that are placed at the intersection of a miniature railroad, causing the LED...