This circuit was found in a 90s Popular Electronics. It produces a muted tone similar to that produced by a bell. The signal must be applied to an amplifier.
This source can supply currents up to 1 A. The circuit is from Motorola's 1993 Linear Interface ICs....
The presented circuit uses a window comparator to keep a relay activated only when the sensor is...
The SCR sector of this circuit can be powered by high voltage AC and instead of the LEDs we can...