This circuit was found in Linear Technology documentation from the 90's. The circuit uses components from that time, and can be powered by 5 V. In these conditions, it can function as a shield.
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...