Variable potential dividers
Extended Tier Only
- When two resistors are connected in series, the potential difference across the power source is shared between them
- A potential divider is a circuit which splits potential difference from a power source, so only a fraction goes to a component (a voltmeter, in the diagram below)
Potential divider diagram
A potential divider splits the potential difference of a power source between two components
- The potential difference across each resistor depends upon its resistance:
- The resistor with the largest resistance will have a greater potential difference than the other one
- If the resistance of one of the resistors is increased, it will get a greater share of the potential difference, whilst the other resistor will get a smaller share
- If one resistor is a variable resistor, the potential difference across the other resistor can be altered
- This means the potential difference across any component in parallel with that resistor can also be altered
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