We found this circuit for musical instruments in the March 1992 Radio Electronics magazine. The circuit has outputs according to the desired scale from a crystal oscillator at the indicated frequency.
Published in an old Popular Electronics, this circuit makes use of components that are still...
Suggested for the control of photographic enlargers, this 1967 General Electric circuit uses still...
Found in old documentation, this oscillator operates with high voltage. The diode must be of the...