Found in Popular Electronics from the 90s, this circuit uses still common components. Its power is 20 W, requiring care when winding the transformers.
This circuit is from a publication from the 70s, but it can be assembled with any diac and a Triac...
This circuit was obtained in a 1983 publication. It is a 1-transistor voltmeter, capable of...
This circuit from Radio Electronics magazine, March 1994 edition uses two LM388 bridged, providing a 4...