This circuit was obtained from the Encyclopedia of Electronic Circuits volume 5 of 1995. The circuit uses the 4001 CMOS to obtain hysteresis in the sensor feedback.
The frequency of this circuit is approximately 1 Hz. Whenever the output is at low level, the LED...
This circuit can be used in a digital measuring or shield interface. The circuit is from old...
In the figure we show how to implement a TTL photo-trigger with the 7413. This circuit can be used...