Electric Current: Sources, Circuits and Current
How charges are set marching in step, and how we measure their flow
Big Idea: An electric current is the ordered (directed) motion of charged particles. In the last two topics you met electric charge and the electric field; now those charges start to move together, and that flow is what lights a lamp, spins a motor and warms a kettle.
By the end you will be able to:
- say exactly what an electric current is and what must be present for it to flow;
- explain what a current source does and name several kinds;
- read and draw a simple circuit diagram with its standard symbols;
- state the agreed direction of current and how it relates to electron motion;
- use the formula for current strength I = q/t and connect an ammeter correctly.