but hard to actually describe in a manner which may be clear to another
skin1235,
Mar 30, 3:34am
a 12v 18w bulb , what does it draw = I W V in the triangle shows 18W above 12V, amps unknown 18W divided by 12V = 1.5 I ( amps)
what resistance does it have = I V R shows 12V above 1.5 I (amps) ,resistance unknown 12V divided by 1.5 I (amps) = 8 ohms resistance ( R)
clear as mud
steelman3,
Mar 30, 2:38pm
maybe its the algebra blowing yr mind.
you may need to spend a few evenings with a maths book.
farwest,
Mar 30, 3:03pm
Wait till you get to AC, and have to take phase angles into account.
crazy126,
Mar 30, 3:42pm
thanks very much guys. all the comments have been helpful.
It might be clear as mud to you skin1235 but alas its not to all of us but your post has helped me a lot thats exactly what i was struggling with working out the ohms of a circuit that had volts and watts only.
i am going to go back to having a crack at it today.
skin1235,
Mar 30, 3:48pm
mate, how clear is mud anyway! lol don't panic, you will find a method of calculating that clicks for you, and then you'll be wondering why you found it so difficult before the above works for me, and I accept it may not suit everyone
lyonruge,
Mar 30, 7:02pm
A little, but close. Ohms law states - The current flowing in a circuit is directly proportional to the voltage, and inversly proportional to the resistance. Once you understand this, the triangle diagrams are easy to use.
tonyrockyhorror,
Mar 30, 9:41pm
Ohms ain't the boss of me so I don't care about his 'law'!
cowlover,
Mar 31, 4:59am
I just use a multimeter - works for me and nothing to remember.lol
clark20,
Mar 31, 5:12am
Now go measure the bulbs' resistance and see what you get.
V = I*R so you want current divide both sides by R
V/R=I*R/Rbut anything divided by its self equals one and one times anything equals itself
so you have V/R=I
if you want Rdivide both sides by I but I/I =1 andI times anything equals itself
so you have
V/I= R*I/Iwhich is
V/I = R
thats algebra you can do anything to the equations as long as you do the same thing to both sides
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