This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
This circuit allows the detection of RF signals using the lowest range of direct currents of a...
The MC496 integrated circuit used in this application is not common today. Motorola's circuit...
This window comparator circuit was found in a Popular Electronics from the 90s. The circuit has a...