In electronics, a B battery is any battery used to provide the plate voltage of a vacuum tube. It is sometimes colloquially referred to as a "dry battery" (although there's no reason why a "wet" battery of suitable voltage couldn't be utilised for the purpose) The term comes from the days of valve (tube) radios when it was common practice to use a dry battery for the plate (Anode) voltage and a rechargable lead/acid "wet" battery for the filament voltage.

Even when the plate voltage rail is fed by a power supply rather than a battery, it is generally referred to as the "B+" line.

See also

• A battery (vacuum tubes)
• C battery (vacuum tubes)

External link

• Instructions for Operating The Crosley 51 Radio Receiver Examples of usage of A, B, and C batteries in an early radio.

Electric batteries | Vacuum tubes | Battery shapes