This circuit was found in a Popular Electronics from the 90's. The CMOS integrated circuit used is not very common nowadays. The range depends on the infrared LEDs. R7 can be changed.
This circuit was found in an American documentation from 1968. The circuit generates ladder-shaped...
This circuit keeps an LED on briefly when S1 is pressed. The time depends on C1. The circuit is...
This circuit was found in old documentation, but it adapts perfectly to modern applications with...