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 is from a 1972 Motorola publication. Some of the used transistors can still be found,...
This circuit controls 6 LEDs in two sets with the phase change cycles controlled by a 555...
Originally created to power an 80's RTTY printer, this circuit can be used in other applications. The...