This diagram was found in the November 1972 issue of Radio Electronics magazine in an article describing benchtop equipment. The transistors are of the time and the frequencies are given by the coils.
This circuit is designed to control static loads fed by direct voltage. The circuit is from...
The 4046 PLL is uncommon these days. This circuit was found in the August 1994 issue of...
This two-transistor circuit was found in American documentation from the 1990s. The circuit can use...