B-Battery

In electronics and telecommunications, especially during the early 20th century, a “B-battery” referred to a type of battery used to supply the plate or anode voltage (high voltage) to vacuum tubes or valves in electronic circuits. It was also known as an anode battery because it powered the anode or plate circuit of the tubes.

The B-battery typically provided a higher voltage (often around 90 volts or more) compared to the lower voltages provided by other batteries such as A-batteries (filament or heater batteries) which powered the filament circuits. In the UK, this high-tension battery was indeed referred to as the High-tension battery.