This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM backup battery. Resistor R1 determines the battery charge.
I got this circuit from a 1977 English magazine. It can still be easily assembled, as the...
Using an era germanium transistor, this 1960s circuit reverses the phase of relatively low...
This mid-frequency amplifier circuit was found in an American publication from the 1950's. The...