This circuit was found in a 90s Popular Electronics. It generates tones given by the oscillators and can be changed. The circuit already includes an amplification stage.
This audio-driven relay was published in the July 1977 issue of Radio Electronics magazine. The...
This circuit can be used for signaling a panel with a common incandescent lamp. The lamp will...
This crystal oscillator is indicated for the calibration of IF steps of common radio receivers. The...