Ampere-hour
An ampere-hour or amp-hour (symbol Ah , A·h, A h) is a unit of electric charge, with sub-units milliampere-hour (mAh) and milliampere second (mAs). One ampere-hour is equal to 3600 coulombs (ampere-seconds), the electric charge transferred by a steady current of one ampere for one hour.[1]
The ampere-hour is frequently used in measurements of electrochemical systems such as electroplating and electrical batteries.
The commonly seen milliampere-hour (mAh or mA·h) is one-thousandth of an ampere-hour or 3.6 coulombs. Small batteries (such as ones in laptops) are often rated in millampere-hours.
A milliampere second (mAs or mA·s) is a unit of measure used in X-ray diagnostic imaging and radiation therapy. This quantity is proportional to the total X-ray energy produced by a given X-ray tube operated at a particular voltage.[2] The same total dose can be delivered in different time periods depending on the X-ray tube current.
The Faraday constant is the charge on one mole of electrons and is approximately equal to 26.8 ampere-hours, and is used in electrochemical calculations.
External links
- Batteries - a glossary of common terms.
- ^ "Full Conversion Table (sorted by Category)" Allmeasures.com, 2004, webpage: AM-Conversion-table.
- ^ X-ray Safety Handbook, 9.0 Terms and Definitions, VirginiaTech Environmental, Health and Safety Services