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.
We found this circuit in a publication from the 1970s. It produces intermittent clicks on a...
We found this circuit in the 1994 National Semiconductor Linear Applications Handbook. The circuit is...
This circuit is from 1977 Radio Shack documentation. The circuit modulates an LED (which can be...