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Edexcel IGCSE Physics · Spec 2.7

Current-Voltage (I-V) Characteristics

Current-voltage graphs for a resistor, a filament lamp and a diode.

Physics revision video

Current-Voltage (I-V) Characteristics

Spec 2.7

What you need to know

  • Describe how to obtain an I-V graph
  • Recognise the graphs for a resistor, a lamp and a diode
  • Explain the shapes

Active recall

Quick check

Answer each question before opening the answer.

What does the I-V graph of a fixed resistor look like?

A straight line through the origin — current is proportional to voltage.

Why does a filament lamp's I-V graph curve (S-shape)?

As current increases the filament heats up, so its resistance increases.

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