Electricity

Charge and current

Electric charge ($Q$) is measured in coulombs (C). Current ($I$) is the rate of flow of charge:

$$I = \frac{Q}{t}$$

measured in amperes (A), where $1\ \text{A} = 1\ \text{C/s}$. Current is the flow of (negative) electrons, but conventional current flows from + to −. Current is measured with an ammeter placed in series.