C battery

8.1

A small cell that gives steady voltage to set the grid of an old radio tube

noun

Archaic

: batería C

Before transistors, the C battery played a crucial role in setting the grid voltage of vacuum tubes.

Examples

The old radio requires a C battery to function.
The technician replaced the old C battery in the vintage radio to restore its proper function.
Collectors of antique electronics often search for period-correct C batteries to complete their restorations.
Do you have a spare C battery?
Before transistors, the C battery played a crucial role in setting the grid voltage of vacuum tubes.
The technician replaced the old C battery in the vintage radio to restore its proper function.
Collectors of antique electronics often search for period-correct C batteries to complete their restorations.

Surface Forms

C battery singular

C batteries plural

Morphology

C + battery

The element 'C' here is an arbitrary technical label/size and does not contribute a predictable semantic component that signals 'a battery used to maintain grid potential in a vacuum tube.' Even a learner who knows the letter 'C' and the word 'battery' would not be able to infer the specialized historical/technical function from the constituents alone. This is a convention-driven, domain-specific term, so the meaning is not compositionally derivable for a B1 learner.

Etymology

C battery comes from early radios that used several batteries labelled 'A', 'B' and C; the C battery was the third and provided a small, steady electric voltage to the 'grid', a control wire inside a glass tube. So the name simply means the small battery used 'to set the grid voltage'.