This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit drives a buzzer, but a relay can be used to activate an external load.
In applications where there is no danger of any contact with live points on the circuit by the...
This is an LED effect that we found in a 1988 documentation. The circuit drives LEDs with a...
In the figure we have the way to implement a TTL Schmitt trigger for 60 Hz signals, obtaining...