This circuit from a 1966 General Electric manual makes use of an SCS. The time is given by the emitter capacitors of the unijunction transistor.
This circuit is from a 1979 publication. The sensor consists of plates or screens that, when...
Found in an 80's documentation this circuit uses an integrated from the uncommon era today. Other...
This circuit was found in a Popular Electronics from the 90s. It uses a LASCR which is a photo-SCR...