This circuit was obtained in a Hands-On Electronics from the 90's. The circuit turns on one LED at the end of the timer, erasing the other. The timing can be increased by changing C1.
Disabling this circuit from a 2002 documentation can only be done by pressing 4 keys in a correct...
This circuit was obtained from a manual of the integrated circuit itself, but can be applied to...
This simple 2004 circuit uses a common sensor used in television and other equipment. It checks...