PHYSICS CONNECTION
A potential divider uses shared current
Two series resistors carry the same current, so their potential differences are proportional to their resistances. This gives the potential-divider equation.
Vout = Vin R₂/(R₁ + R₂)
Follow the reasoning
- Identify the resistor across which output is measured.
- Find its fraction of the total series resistance.
- Multiply that fraction by the input voltage.
OFFICIAL OCR QUESTIONS
Try it in a past paper 1
Open the question, then use its mark scheme to check your work.
Question 3(b)
Calculate and evaluate the output of a thermistor potential divider.
A curated collection checked against the question papers and mark schemes; not a complete past-paper catalogue. Links open official OCR PDFs in a new tab.
ORIGINAL PHYSICSUK QUESTIONS
Put the ideas to work
More practice is on its way
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Specification outcomes (4)
- 4.3.1(c) Calculate total resistance of resistors in series using R = R₁ + R₂ + …
- 4.3.1(e) Analyse circuits with components including both series and parallel arrangements.
- 4.3.3(a) Describe potential divider circuits with fixed components and potentiometers.
- 4.3.3(c)(i) Use potential divider equations Vout = (R₂ / (R₁ + R₂)) × Vin and V₁ / V₂ = R₁ / R₂.