resistance physics – 12.1.5 series and parallel resistor circuits understand how the resistance...
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![Page 1: Resistance Physics – 12.1.5 Series and parallel resistor circuits Understand how the resistance of components add up in a circuit Summate resistor](https://reader036.vdocuments.net/reader036/viewer/2022062321/56649f0b5503460f94c1eaf5/html5/thumbnails/1.jpg)
Resistance
Physics – 12.1.5 Series and parallel resistor circuits
Understand how the resistance of components add up in a circuit
Summate resistor networks by applying the formulae in various situations
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GCSE Background
From GCSE physics we already know that;
V = IR
So simply in this circuit the resistance of the bulb is 12. This is a measure of how much the bulb resists the flow of electrons.
We should also have some idea of these graphs which show a “characteristic” behaviour of different conductors when we graph at V & I
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Circuit Rules For resistance calculations at AS you can use the premise of the
following rules;
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Series Resistance
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Parallel
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Generalised FormulaeSo all this leads us to a generalised formulae for any number of resistance.
In Series resistance is simple but for Parallel resistances we must use the reciprocal.
NB: when multiplying out the second formula make sure you treat all terms equally!
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Test it out….If all the bulbs are of equal resistance
answer the following;
1) Find all the meter readings
2) What is the total resistance of the bottom branch
3) If I swapped all three bulbs for one bulb what resistance should it be so that the current flow in the main branch is still 3A (i.e. combine all resistances using formulae)