Definition

1. Noun:
   • A unit of electrical charge: An ampere-hour is a unit of measurement for electric charge. It represents the quantity of electricity transferred by a steady current of one ampere flowing for one hour.

Usage

• The ampere-hour is commonly used to specify the capacity of batteries, such as those in cars, phones, or other electronic devices. It indicates how much total charge a battery can store and deliver.
• It is a non-SI unit, but it is widely accepted and used in practical applications, especially in electrical engineering and consumer electronics.

Examples

Advanced Usage

• "Milliampere-hour (mAh)": A subunit equal to one-thousandth of an ampere-hour. It is frequently used to describe the capacity of smaller batteries, like those in smartphones and laptops.
  • My phone's battery is rated at 4000 milliampere-hours (or 4 ampere-hours).

Variants and Related Words

• Coulomb: The SI unit of electric charge. One ampere-hour is equal to exactly 3600 coulombs.
• Ampere (A): The SI base unit of electric current. The ampere-hour is derived from this unit.
• Watt-hour (Wh): A related unit of energy, which incorporates voltage. For a given voltage, ampere-hours can be converted to watt-hours.

Synonyms

• Ah (abbreviation): The standard abbreviation for ampere-hour.
• Amp-hour (informal variant): A common spoken and written variant.

Notes on Meaning

• The ampere-hour is a measure of charge capacity, not instantaneous power or energy. It describes the total amount of electric charge available.
• It is crucial to distinguish it from the ampere, which measures current (the of flow of charge), while the ampere-hour measures the total of charge that has flowed.

Noun

1. a unit of charge equal to 3600 coulombs