Found in an Electronics World of 1968 this circuit can use any SCR and diodes depending on the load. The circuit is full wave and the unijunction can be 2N2646.
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...