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 with 3 receivers and is intended for low frequencies (medium wave range). We...
Using two of the 4 NAND gates of the integrated 4001, the circuit in the figure activates the...
This circuit allows you to superimpose the signal from the microphone to that of the music with...