Found in an Electronics World of 1966, this circuit makes use of FETs of the time. Modern equivalents can be used. The high voltage supply suggests its use with tube amplifiers.
Found in Popular Electronics from the 90s, this circuit can be used as a warning shield for...
This CA3140 follower was found in a 1991 publication. The transistor may be the BC548 and the...
This circuit was published in an English magazine from 1980. The magazine no longer exists, but...