Frequently Asked Questions (FAQ) Electric Green Planet .com!
General Question: What is an ampere hour?
Answer: 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 3,600 coulombs (ampere-seconds), the electric charge transferred by a steady current of one ampere for one hour.
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 (i.e., 3.6 coulombs), and is a technical term for how much electrical charge a particular battery will hold. Small batteries, such as those in laptops and digital cameras, are often rated in millampere-hours. As an example, digital camera batteries with higher mAh values theoretically last longer without requiring a recharge, allowing one to take more photographs before having to replace the batteries.
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. 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.
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