Originally indicated as an alarm alert in a 1990s US publication, this circuit can be used as a shield to control a strobe lamp. The sensor is a optocoupler with LDR.
We found this circuit for guitar training in an English documentation from 1989. The components are from...
This circuit produces a voltage drop in the first pulse, turning off the relay. On the second...
Readers who like sound or sound effects cannot fail to examine this interesting circuit. What we...