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Formula Electric current (definition) Electric charge    Time

Formula
Formula: Electric current (definition)
Electric current between plus and minus pole
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Electric current

Unit
Electric current is the amount of charge \(Q\) that crosses the cross-sectional area of a wire within a time period \(t\). Electric current is therefore charge per time.

Electric charge

Unit
This is the amount of charge that has passed through the cross-sectional area of a wire within the time \(t\).

If the individual (positively) charged particles carry the charge \(q\) and \(N\) particles have passed through the cross-sectional area in the time \(t\), then the charge passed through:\[ Q ~=~ N \, q \]

Time

Unit
Time period during which the charges were counted through a cross-sectional area.