⚡️ Electric current is the flow of electric charge carriers (usually electrons) through a material. Think of it like a river of tiny charged particles moving from one place to another. When we say a current flows, we mean that a certain amount of charge passes a point in a given time.
Imagine a pipe filled with water. The water molecules are like electrons. The flow rate of water (litres per second) is analogous to electric current. The faster the water moves, the higher the current. The amount of water that passes a cross‑section per second is the current.
Picture cars (electrons) traveling along a road (conductor). The number of cars passing a point each second is the current. If the road is wide and cars move quickly, the traffic flow is high – just like a strong electric current.
The symbol for current is I and its SI unit is the ampere (A). One ampere equals one coulomb of charge passing a point per second:
\$I = \frac{Q}{t}\$
| Quantity | Symbol | Units | Formula |
|---|---|---|---|
| Electric current | I | A (ampere) | \$I = \frac{Q}{t}\$ |
| Charge | Q | C (coulomb) | \$Q = I \times t\$ |
| Time | t | s (second) | \$t = \frac{Q}{I}\$ |
A battery supplies a current of 2 A to a light bulb. How much charge passes the bulb in 5 seconds?
Use \(Q = I \times t\):
\$Q = 2\,\text{A} \times 5\,\text{s} = 10\,\text{C}\$
So, 10 coulombs of charge flow through the bulb in that time.
Electric current is simply the rate at which electric charge moves through a conductor. Just like water flowing in a pipe or cars on a road, the amount of charge that passes a point per second determines the current. Understanding this flow is fundamental to all of physics and engineering.