alternator
AHL-ter-nay-ter
/ˈɑːl.tɚ.neɪ.tɚ/
An electrical generator in a motor vehicle that converts mechanical energy into alternating current to power electronics and charge the battery.
Distinct from the battery itself; while the battery starts the car, the alternator keeps electrical systems running and recharges the battery while driving.
The story behind the word. Derived from Latin 'alternare' (to alternate). The device generates alternating current (AC), which is then converted internally to direct current (DC) for automotive use. Alternators replaced older direct-current dynamos in vehicles during the 1960s because they were lighter and more efficient.
Word relationships
- generator: 'Generator' is a broad term for any mechanical-to-electrical energy converter, whereas 'alternator' specifically produces alternating current.
Commonly confused with
- battery: The battery stores chemical energy for starting the car, while the alternator generates electrical power when the engine is running.
Word family
- alternate (verb): to occur or exist turn by turn
- alternation (noun): the state of alternating
Collocations
- failing alternator
- alternator belt
- replace the alternator
- alternator output
Example sentences
- "When the headlights dimmed every time the driver accelerated, the mechanic suspected a failing alternator." Troubleshooting electrical problems
- "If your car starts with a jump-start but dies immediately after removing the cables, the alternator is likely faulty." Diagnostic explanation
Memory hook
The ALTERnator ALTERnates mechanical motion into electrical current. Alternates motion into battery power.
When not to use
Do not use to describe household chemical batteries or solar cell arrays.
Fun facts
- Military vehicles were among the first to adopt alternators during WWII because their radio equipment required high electrical output even while idling.
Related words
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