# Interpreting I–V graphs

I can take readings from I–V graphs and use these to describe the changing resistance of a component.

# Interpreting I–V graphs

I can take readings from I–V graphs and use these to describe the changing resistance of a component.

## Lesson details

### Key learning points

- In forward–bias, a diode has a very small resistance when the p.d. is larger than the threshold voltage.
- In reverse–bias, a diode has a very large resistance and very little current can flow.
- The greater the p.d. across a component, the larger the push on electric charges in the component.
- The resistance of a component is calculated from an I–V graph using pairs of readings and the equation R = V ÷ I.
- The greater the current through a component, the larger the heating effect on it.

### Common misconception

Pupils often cannot apply the main I–V graphs to similar components.

Describe how the p.d. and current in components behaves to draw out similarities that can be used to describe unfamiliar components.

### Keywords

Reverse–bias - When a diode is reverse–biased, it prevents current from flowing.

Forward–bias - When a diode is forward–biased, it allows current to flow.

Threshold p.d. - The threshold p.d. is the potential difference at which a diode allows current to flow.

Fuse - A fuse is a component that has a wire that melts if the current is too high.

Ion lattice - In a solid metal, the regular and repeating pattern that metal ions are arranged in is known as an ion lattice.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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