Current in a circuit is a measure of the flow of charge past a specific point in a circuit.
where DQ is the amount of charge that flows by the
point in a time Dt.
The unit of current is Amperes or
One amp is equivalent to one Coulomb per second. Charge is a
conserved quantity: it cannot be created or destroyed.
Therefore the current that flows into a junction must equal the
current that flows out. For instance, if three wires are attached
at a point as shown below, the total current flowing into the junction is equal to
the total current flowing out:
i1 = i2 + i3
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