Potential Dividers
A potential divider is used to produce a desired potential difference, it can be thought of as a potential selector.
A typical potential divider consists of two or more resistors that share the emf from the battery/cell.
The p.d.s across R1 and R2 can be calculated using the following equations:
This actually shows us that the size of the potential difference is equal to the input potential multiplied by what proportion of R1 is of the total resistance.
If R1 is 10 Ω and R2 is 90 Ω, R1 contributes a tenth of the total resistance so R1 has a tenth of the available potential. This can be represented using:
The ratio of the resistances is equal to the ratio of the output voltages.