This circuit recognizes a tone determined by the tuned input circuit (R3 / R4 / C2). The circuit was found in Radio Electronics from the 90s. The 4046 is not a common component today.
The first circuit, shown in the figure, generates a stepped signal whose frequency depends on the...
This differential amplifier, found in a 1964 Electronic Design, has a gain of 30. The setting can be...
The purpose of this circuit is to control the high and low light of a car, detecting when a...