Current

Symbol I, measured in amperes (A) or milliamps (mA)

Current is how much electric charge flows past a point in the circuit every second.

Current needs a complete loop. Open a switch anywhere in the loop and the current stops everywhere at once.

An LED wants about 10–20 mA (0.01–0.02 A). An Arduino pin can give up to about 20 mA safely, which is why motors need a driver or transistor.

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