This circuit was found in a Popular Electronics from the 90s. It is intended to power the filament of old radio valves in recovery works. It is indicated for tubes that use 5 V of filament.
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...