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.
Found in 1960's Radio Electronics, this circuit provides an audio tone that depends on the logic...
This type of automation is very important because it serves a multitude of applications, ranging from...
Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It...