Electric current
The flow of charge round a circuit, measured in amperes (A). Charge = current x time.
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Analogy
Water flowing through a pipe: current is how much passes each second.
Example
current = 2 Atime = 30 scharge = 2 x 30charge = 60 C
In practice
In a metal wire the moving charges are electrons. Current is measured with an ammeter placed in series.
Practice
Flashcards
- What is the unit of current?The ampere (A).
- What is the formula linking charge, current and time?Charge = current x time.
Questions people ask
What is the difference between current and charge?
Charge is the amount of electricity that moves, measured in coulombs (C). Current is how fast it moves, measured in amperes. One ampere means one coulomb of charge passing a point every second, so charge equals current multiplied by time.
Does current get used up in a circuit?
No. Current is the same all the way round a series loop. Components do not use up the electrons, they transfer energy from them. The charge keeps moving round the loop, picking up energy from the cell and giving it to the bulb as light and heat.