Light Bulbs as Dropping Resistors

1945AugPMThis photo isn’t as sinister as it looks, and nothing untoward is going to happen to the gentleman at the left. The photo is from the August 1945 issue of Popular Mechanics, and these gentlemen are dealing with wartime parts shortages. They’re doing an emergency repair on this set, and need some way to power the filaments of the six-volt tubes. The filament transformer they need is a wartime priority item, so they instead wired the filaments in series and used a 40-watt light bulb as a dropping resistor.

The picture is accompanied by a table showing the resistance of common lamps.