This circuit was found in a 1967 Raytheon manual. The transistors are from the time. Equivalent modern transistors can be tried out.
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...