This circuit, with printed circuit board included, is from a Radio Electronics magazine from July 1971. The SCR can be any equivalent of the 106 series.
This circuit was found in Radio Electronics from the 90s. The transistor is for general use. The...
We found this circuit in a 2005 Linear Technology application manual. The circuit makes use of a...
This circuit is from 1971 American documentation. Transistors are still common except for 2N2060...