This is the circuit for the HM-10ª, an instrument sold by Heathkit. The circuit is from a Radio Electronics from May 1963. The indication is by an analog instrument.
We found this code switch circuit in the January 1999 Electronics Now magazine. Some of the...
We found this circuit for musical instruments in the March 1992 Radio Electronics magazine. The...
This circuit was found in documentation from 1977. Its purpose is to diode-switch the frequency of a VFO....