This 9 V battery eliminator was found in Radio Electronics magazine from June 1966. The transistor is of medium power and must be equipped with a small heat sink.
This circuit was published in a January 1971 issue of Radio Electronics to check television...
Found in Popular Electronics from the 90's, this tuned to infrared modulated receiver uses a PLL....
This 1967 General Electric circuit makes use of an array of 3 (integrated) transistors for an...