This circuit with three transistors was suggested in a Radio Electronics magazine from February 1963. The transistors are types of the time. Power comes from a 12 V battery.
This old 1967 audio preamp uses germanium transistors. It was found in Japanese documentation at...
In the figure we have the conventional configuration of a filter that allows only the frequencies above...
This circuit is from a 1995 Electronics Now. It generates a 1 kHz sinusoidal signal. See in the...