Electricity; Simplified. Busses; Electrified.

During my Cambridge A. Level Physics class, a metaphor for how to explain the underlying principle of the equation for Power (P = VI) came to my mind, which I’ll be sharing here.

First things first, the 3 components of the equation:

• P means “Power”. Which is the product of multiplying Voltage with Amperage.

• Voltage is the amount of energy (or charge) per coulomb.

  • A coulomb is basically a bunch of electrons. Imagine a school of fish, or a flock of birds, that carry something.

• Amperage is the number of coulombs passing through a point per second.

So imagine the following:

On a highway, there is a checkpoint—tollbooth, etc. School buses pass through this checkpoint. Each bus carries an equal number of students. And your job is to measure how many students are crossing the checkpoint per second.

The highway is the electrical wire. The number of school buses passing per second represents amperage (which is number of coulumbs passing through a point per second). The number of students each individual bus carries, represents the amount of energy (in Joules) each individual coulomb carries.

Power is calculated by multiplying the amount of energy per coulomb with the number of coulombs moving past a given point per second. In other words, it’s how many units of energy (i.e. how many “Joules”) are passing that point per second. Or, in our metaphor, how many students are passing through the checkpoint per second. So, to summarize:

Number of students per bus x Number of buses per second = Number of students passing through the checkpoint per second.

Number of Joules per coulomb x number of coulombs passing per second = Number of Joules passing through a point per second

Voltage x Amperage = Power

V x I = P

This metaphor helped me greatly in understanding the concept of power and the equation behind it. I hope it helps you lovely people, too!

Keep learning,

Keep sharing.