Using the 2N2646 this circuit was found in a Radio Electronics magazine from July 1968. The transistors are from the time and the lamp can be replaced by a high-power LED in a current version.
This preamp with a transistor for turntables with crystal capsules was found in a Japanese...
This variable frequency oscillator generates signals that have a recurrence frequency determined by...
This circuit with neon lamp and unijunction was found in the September 1970 Radio Electronics...