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.
Found in a 90s Popular Electronics, this circuit allows to select the operating ranges between...
This circuit was obtained in a 1960 transistor manual from Sylvania. The circuit uses small...
This simple unijunction circuit is from a Radio Electronics from July 1963. It can be assembled with a...