electrics help - work much confused :D

ok so got some work to do for college but im a little lost can some on confirm this for me

ok so scenario: have a 12v parallel circuit no resistors and grounded to the chassis with 2 100w bulbs wired in parallel.

so my understand is both bulbs get 12v, i need to work out the amps for the diagram so 100w/12v= 8.33amp's for each wire going to the bulb. The wire that comes from the battery's + then later on splits off to the two bulbs +'s would be double that of each wire going to the bulbs because its supplying both bulbs ?

and the resistance for each 100w bulb is 12v/8.33amp = 1.44ohms ?

i truly hate electrics ......

thanks for any help if a diagram would help i can make one up

Im not sure i understand what your question is lol, then again i am tired.

[tigersaw]

Each lamp consuming 8.33 Amps.
Total consumption is twice that as its a parallel circuit of two lamps.
Resistance of lamps.. tricky, as they are non linear devices. But in the circumstances you describe you can assume they behave similar to a resistor of 1.44 ohms

[timwilky]

I am not going to do it for you but instead tell you what you need to do.

You need to work out the resistance of the circuit, that is the two resisters in parallel

Then the current for the total circuit can be established from good old V=IR

Do it publish it and I will tell you if you are right.

[21QUEST]

What tigersaw said ie you are correct.

But timwilky has got the right idea

[21QUEST]

Re timwilky's post, a little pointer

V/R x V=W .

Do that for each...

[timwilky]

OK guys I will do it for him, my way

He has already worked out the resistance of a lamp as 1.44 ohms

Total resistance of parallel resistors bulbs = 1/((1/1.44) +(1/1.44)) =0.72 ohms

12/0.72 = 16.66..A

ok so i think this is right ps sorry bout the drawing/image paint for you



EDIT beaten to it by Tim

[timwilky]

That is the most weird diagram I have ever seen, definitely not how to wire a parallel set of bulbs back to earth.

Your current would remain constant over the circuit, you do not have different sections at different current.

Your total resistance on a parallel circuit is the reciprocal of the sum of the recipricals of the parallel resistances. So 0.72 ohms.

[21QUEST]

Hi mate,

Mine would have been slightly different/simpler diagram .

Total resistance is wrong though(refer to timwilky's last post). You've calcilated it as as you would for resistors in series.