This circuit was found in an American publication from 1965. The circuit uses components from that time. No information was given about the excitation transformer. Observe the high input power.
We found this circuit at Modern Electronics in January 1991. The magazine no longer exists, but...
Using a 4046 PLL this circuit generates rectangular signals in three wavebands that depend on the...
This sophisticated circuit using a liquid crystal display was found in Radio Electronics from the...