The configuration shown was found in an old Poptronics but can be easily assembled using a common calculator photocell. The relay is according to the supply voltage.
May 2017 - Torex's XBP14E5UFN, an array of TVS circuit protection diodes with only 0.8 pF of...
Found in a 1965 CQ magazine, this circuit uses period components. The unijunction transistor can...
This circuit is from a 1974 publication, and the integrated circuit can be replaced by the 7905....