Found in American documentation from the 1980s, this circuit has a diode feedback. At the exit we have an indicator LED. The LM3900 is a transconductance operational amplifier.
With a touch of the push button the lamp is switched on. A new touch and the lamp go out, in this...
This circuit was obtained from Maxim documentation. The circuit has 4.5 and 5.5V thresholds for...
This circuit has a configuration very explored in our projects. The range can exceed 200 meters and...