Suggested by General Electric in a 1967 publication, this circuit uses the D13T1, an uncommon SCR today. This component is triggered by the anode.
If you have a common analog multimeter, you can increase its input resistance in the measurement of...
Found in Philips' 90s documentation, this small source can use modern transistors like the BD135...
The circuit is from an Electronics Hobbyst Handbook from the 90s, being valid for panels of the...