Electric Current
Electric current explained: what is actually moving, why conventional current runs opposite to the electrons, and what typical currents look like.
Questions people ask
Is it the volts or the amps that kill?
The current through the body does the damage. Voltage matters because it determines how much current can be driven through your resistance — but 30 mA across the chest is dangerous whatever produced it.
Why does a thin wire get hot?
Less cross-section means more resistance, and power dissipated is I²R. Doubling the current quadruples the heating, which is why cable sizing follows current, not voltage.
What is the difference between AC and DC current?
DC flows one way continuously. AC reverses direction periodically — 50 Hz or 60 Hz on mains — which lets transformers change its voltage efficiently.
Does this page work offline?
Yes, after the first visit. The service worker caches it, so the reference stays available with no connection.
Last updated 22 August 2026