# ELECTRICAL CIRCUITS

Electrical circuits? How do they work then? Witchcraft? Voodoo? What is current? How is it different to voltage? Find out here as you indulge in this wonderful **circuit builder** made by those wonderful people at Phet! Absolute physics legends. Suggestions for **investigations** can be seen below in the embedded power point presentation! Let us know what you think or these - are they useful? Would you like to see more or less of them? Contact us via our contact page.

### INVESTIGATIONS!

**CURRENT AFFAIRS...**

So what actually is electric** current**? We know it is measured in amps but what does it actually mean? Officially, its the **rate of flow of charge**. The video below explains, welcome to the weird world of **charge**, current and **coulombs!** Finally learn what is meant by Q = I x t and how to use this equation.

### KEY CHARGE POINTS

Charge is a property of matter

Charge can be positive (+) or negative (-).

Charge is measured in Coulomb C.

In a circuit, negative charge (electrons) moves from one point to another.

Current tells us how fast the charge moves.

The formula for charge is:

Q=I x t

where Q is charge, I is current, and t is time

**Potential Difference**

So we all know the the current it the rate of low of charge around the circuit. But what about** potential difference**? This is the posh name for** voltage**. It tells us how many** joules** of energy are transferred per coulomb of charge. But what does it actually mean? Find out here.

### POTENTIAL POINTS OF INTEREST

Potential difference is a measure of energy, per unit of charge, transferred between two points in a circuit.

Potential difference is also known as voltage and is measured in volts (V).

The formula for potential difference is:

V= E / Q

where V is potential difference, E is energy, and Q is charge.

The formula for potential difference can also be written as

V=I x R

where V is potential difference, I is current, and R is resistance.

Potential difference can be measured by a

**voltmeter**, which is connected in parallel with the component