We found this circuit in a Radio Electronics from October 1963. The circuit uses an output transformer with a center tap. The trimpot is adjusted for higher gain and lower quiescent current.
This circuit has an opposite action to the previous one, triggering when light falls on the...
This configuration appears elsewhere on this site. We found it in a Motorola manual from the 70s....
Indicated to be used as a clock, this circuit was found in old documentation. The operational of...