Found in 1969 RCA documentation, this circuit maintains constant current in the filament of a lamp or in a heating element. The circuit makes use of period components.
I found this circuit in a 1986 English magazine. It can still be easily assembled, replacing the...
In short wave receivers or in the recovery of signals from scratched discs this circuit can be...
This very low consumption circuit can be powered by a solar cell. The time indication is given by a...