If you have an electric meter, it shows energy consumed in Watts per hour. This energy has an amount, Joules that is. But in a battery there is energy stored that also has an amount. So it should be in Joules as well. But the unit is different: Ah,(or mAh).Why is that and what is the difference between these two u
In: Physics
No. It displays energy in Wh (watt hour) because thats an energy unit. 1 W := 1 J/s is a unit of power by definition energy per unit time. So 1 Wh = 3600s × 1 W = 3600 J of energy. Thats not that much so we usually use 1 kWh = 1000 × 1 Wh.
We don’t measure battery life by how much energy it stores but by how much charge it stores. Current by definition is charge/time and 1 A (ampere or amp for short) = 1 C/s (Columb per second). So 1 Ah (ampere hour) is a unit of charge. But 1 C is a large quantity of charge so we use 1 mAh as a unit which is 1/1000 × Ah.
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