a battery
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Definition
Noun: 1. A type of battery used to supply power for heating the filament (cathode) in a vacuum tube: This is a specific, technical term from early electronics. An "A battery" provides the low-voltage, high-current power needed to make the filament in a vacuum tube (or valve) glow hot, which is essential for the tube to function by emitting electrons.
Usage Notes
- This term is now largely historical and technical. It is primarily encountered in the context of antique radios, early electronics, or historical technical manuals.
- It is part of an old naming convention for power supplies in vacuum tube circuits:
- A battery: Heats the filament (provides "A" power).
- B battery: Provides the high voltage for the plate/anode (provides "B" power).
- C battery: Provides bias voltage for the grid (provides "C" power).
- In modern language, the term "battery" alone almost never refers to this specific type unless the context is explicitly about vintage tube-based equipment.
Examples of Usage
- Noun:
- The old radio required a fresh A battery to power the tube filaments.
- In the circuit diagram, the A battery is connected directly to the filament pins of the vacuum tube.
- Restorers of antique electronics often need to find a suitable replacement for the original A battery.
Advanced Usage
- The term can be used metaphorically or humorously to refer to a fundamental, low-level power source that enables a more complex system to operate, though this is very rare.
- "Coffee is my A battery; without it, none of my mental circuits function."
Variants and Related Words
- B battery (n): The battery that supplies the high-voltage DC potential to the plate (anode) of a vacuum tube.
- C battery (n): The battery that supplies the bias voltage to the control grid of a vacuum tube.
- Filament battery (n): A synonym for "A battery," describing its function more directly.
- Heater supply (n): A modern technical term for the power source that heats the cathode in a vacuum tube or a cathode-ray tube (CRT).
Synonyms
- Filament battery
- Heater supply (in modern terminology for similar function)
- Low-voltage power supply (descriptive, not a direct synonym)
Antonyms
- B battery: While not a true opposite, it serves the complementary high-voltage function in the same system.
Noun
- the battery used to heat the filaments of a vacuum tube