Found in a 1980’s documentation, this circuit must have its signal applied to an amplifier stage. The unijunction transistors can be 2N2646.
We have articles on the site with the name “lamp test” for this configuration found in a Popular...
The circuit we present is suggested by Linear Technologies (www.linear.com) and makes use of an...
This current sensing circuit for applications up to 10 A has been found in a Linear Technology...