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using ohms law outside of vaping
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gentlydoingit* Offline
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Post: #1
using ohms law outside of vaping
I got posed a question today that I was sure I could answer, turns out I couldn't Confused my own understanding of the math failed and I couldn't see a way to work it out on steam engine either.

So.. ballast resistor to coil pack.. if I've got 12V going into a 1ohm resistor what voltage should I expect coming out? Same question with a 0.6 ohm resistor.

What formulae am I missing?

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21-12-2016 01:42 AM
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Michael Offline
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Post: #2
RE: using ohms law outside of vaping
This doesn't seem to be a question for Ohm's Law. If you know the voltage and resistance, then Ohm's Law can get you the amps or wattage, not the output voltage after going through the resistor. At least, not that I know of. The question really doesn't make sense from a vaper's understanding of Ohm's Law, since when we use it for vaping, we just assume the voltage is whatever the mod tells us it is (or whatever the formula tells us it is, based on resistance and wattage). 

So Ohm's Law can tell you that with 12V and 1.0 ohms, you're looking at 12A and 144W. Or at 12V and 0.6 ohms, you're looking at 20A and 240W. But I don't know what formula you'd use to check the output voltage of a circuit like that. Most certainly not a formula from Ohm's Law. 

Could they possibly mean something else, like a 12A current? I thought I knew Ohm's Law fairly well, but that question just doesn't make sense in my small brain as it is, and you're giving me a crisis of identity as a math nerd, unless they're just trying to determine the voltage sag across a resistor. This article on voltage dividers is the only thing I can really find about this, and it's talking about multiple resistors used to intentionally decrease the voltage of a circuit. 
21-12-2016 02:58 AM
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Don Offline
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Post: #3
RE: using ohms law outside of vaping
Resistors do have a volt drop across them, but their primary function is to limit current.

You can use volt drop across a component to measure resistance with Ohm'sw Law.

I'm afraid my knowledge kinda stops there. Me, I'd measure the result.

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21-12-2016 07:05 AM
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gentlydoingit* Offline
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RE: using ohms law outside of vaping
The problem is I can't measure the output propperly as we think there's a fault with a controller that compensates for volt drop caused by cranking the starter motor. The output is 6v, we can't measure amps until the alternator kicks in as it's got supressors and regulators built in, unfortunately the car won't start hence the checks.
 12a over 1ohm is 12V Mail1 but how that relates to volts in and out I don't know Scratch_one-s_head
Ohms law should work shouldn't it?, it's a set of laws that predict the effect of resistance on current, if knowing Vin and Vout would tell you resistance then there's a formula to attain all three parts of the equasion..  Google is giving me nothing, probably because I'm not asking the right question Dash2

I'll take another approach, cheers guys Good

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21-12-2016 11:47 AM
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TinWhisker Offline
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Post: #5
RE: using ohms law outside of vaping
Try this...

http://www.rapidtables.com/calc/electric...ulator.htm

http://www.electro-tech-online.com/artic...stors.452/
21-12-2016 05:20 PM
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gentlydoingit* Offline
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Post: #6
RE: using ohms law outside of vaping
Dam you math! I seem to have cerebral flatus followed by auto shutdown when confronted by numbers and squiggles Wacko2 I'm sure the answer is there somwhere though, thanks tw.

We put 12V to the coil with 140mm of kanthal, bypassing the resistor.. it worked, the controller was screwed after all. Pardon All fixed now Smile

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21-12-2016 06:38 PM
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VapeChic88 Offline
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Post: #7
RE: using ohms law outside of vaping
I find this calculator to be super helpful you should give this one a shot, it's the best I've found:-)
26-12-2016 10:30 PM
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