This circuit is from an1966 General Electric documentation. The Triac can be equivalent to 6 A or more, mounted on a good heatsink. Any diac can be used.
Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit...
This preamplifier circuit for turntable cartridges was found in the March 1994 issue of...
E) This circuit was found in documentation from the 1980s. The integrated circuit used is not very...