Designing a circuit given a fixed resistance

[kenhung123]

If you are given 10 resistors of 10ohm and asked to create a circuit so the total resistance is 7, how would you go about it?

[Stroodle]

5 in parallel, then place this in series with 2 in parallel.

[kenhung123]

How did you work that out?

[Stroodle]

Just figured that two 10 ohms in parallel give 5, and 5 in parallel give two. Then added them together.

[cameron_15]

if you had to use all ten then connect 4 in parallel in series with another 4 in parallel in series with another 2 in parallel.

its just annoying manipulation of resistance in series and parralel rules. just a bit of playing about, trial and error. Well for me anyway

[lachymm]

I remember doing this question, it can be time consuming but if you realize that the more resistors in parallel = less resistance then just keep adding resistors til you get the desired resistance eg try and find resistors in parallel that give whole numbers in this case 2 in paralell gives 5 Ohms and 5 in paralell gives 2 Ohms, i realize i have explained this poorly but its a trial and error thing, if you get this in an exam leave it for last as it might throw you off?