This crystal oscillator is indicated for the calibration of IF steps of common radio receivers. The transistor admits equivalent as 2N2222 or BF494. The circuit is from an old American publication.
This circuit can be used in decoration or to draw attention, in a “fake” assembly for example. What he...
Found in an old Radio Electronics, this circuit uses current components, used to rectify AC...
Found in an American documentation from the 1960s, this circuit uses transistors from the time. The...