---
categories:
  - Electronics
tags: [physics, electricity]
---

# Current

When an appropriate external force is applied, the movement of electrons is from negatively charged atoms (negative ions) to positively charged atoms (positive ions). We call this **electrical current**. 

We use the symbol $I$ to stand for current in equations. 

> The amount of current is the sum of the charges of the moving electrons past a given point.

## Coulombs and amps

We measure **charge** in Coulombs ($C$). A Coulomb is an aggregate of the charge of several electrons because their charge is so small: $6.24 \cdot 10 ^{18}$ electrons. 

We measure **current** in amps. When one coulomb of charge moves past a point in one second it is called an **ampere** (amp) represented as $A$.