An ampere (amp) is created by the flow of electric current; specifically, it's related to the force generated by that current.
Understanding the Ampere
The ampere (A) is the base unit of electric current in the International System of Units (SI). Historically, its definition is intertwined with the force exerted between current-carrying wires.
Historical Definition
The reference provides an insight into the ampere's original definition:
- The ampere was initially defined based on the centimetre–gram–second (CGS) system of units.
- The abampere (the CGS unit) was defined as the current that creates a force of two dynes per centimeter of length between two wires one centimeter apart.
Simplified Explanation
In simpler terms, the ampere is a measure of how much electric charge flows past a point in a circuit per unit of time.
Force and Current
- Electric current flowing through a wire creates a magnetic field around the wire.
- If you have two wires carrying current, their magnetic fields interact, resulting in a force between the wires.
- The magnitude of this force is directly proportional to the amount of current in each wire. This relationship is the basis for the historical definition of the ampere.
Modern Context
While the original definition is based on force between wires, the modern definition of the ampere is more precise and linked to fundamental constants:
- It's now defined in terms of the elementary charge and the second.
Example
Imagine two parallel wires, 1 cm apart, each carrying the same amount of current. If the force between these wires is 2 dynes per centimeter of length, then each wire is carrying one abampere of current. One abampere equals 10 amperes.
Summary
An ampere (amp) represents the amount of electric current. This flow generates a force, and the magnitude of this force between current-carrying conductors defines the unit. The amount of electric charge flowing per unit time is what constitutes the ampere.
