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.
This circuit provides a negative supply for circuit biasing. The current is very low. The voltage...
This very low voltage circuit with the LMV321 was obtained from its own datasheet. The circuit can be...
This circuit was found in a Modern Electronics from 1990. It activates an old electromechanical pulse counter,...