Resistors in Parallel

[mickw]

OK, brain broken 

e.g.
If you have a 100 ohm resistor and a 200 ohm resistor and connect them to a supply using one plug, do they remain individually at 100 and 200 or do they behave as resistors in parallel.

I'm thinking of 2 dew heaters sharing the same plug.

The numbers 100 and 200 are meaningless

[Mac]

their individual resistance dosent change, the overall resistance does.

if you have them in series its the same as a single 300 ohm resistor.

If you have them in parallel its the same as a single 120 ohm resistor.

[MarkS]

If you have them in parallel its the same as a single 120 ohm resistor.

If they're in parallel it's like a 67 ohm resistor not 120 ohm.

Mick,
a 100 ohm dewheater will consume 1.44 amps
a 200 ohm dewheater will consume 0.72 amps
Put them in parallel and together they consume 1.44+0.72 = 2.16 amps
Mark

[mickw]

So 2 dewheaters sharing the same plug won't burn one of them out 

Makes sense now, all dewheaters are connected to the same battery which is the same as one plug anyway 

I think you know why I am so cautious now 

[Mac]

If they're in parallel it's like a 67 ohm resistor not 120 ohm.

i'll use a calculator next time,

[Ian]

bear in mind that the equivalent resistance only matters to the battery. As far as each resistor is concerned, it's seeing the same voltage and will draw the same current as it would if it was on it's own.

that is, it will heat just as efficiently connected in parallel to another as it would on it's own. the difference being your battery will run down sooner.

Note, this is assuming internal resistance is negligible, which it is, until you start to draw scary (car starting) sort of amps.