We found this circuit in a magazine 73 for radio amateurs from the 80's. The circuit makes use of an epochal component which is programmed according to the table beside the diagram.
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...
This linear LED scale circuit was found in the February 1992 issue of Radio Electronics magazine. Note...
This amplifier stage without an output transformer was found in Radio Electronics magazine from...