Found in an Electronic Design and 1970s, this circuit uses transistors of the time. The transistors can be replaced with equivalents and the relay is 12 V depending on the power supply.
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...