Calculating Voltage drop issues

Try this: http://www.stealth316.com/2-wire-resistance.htm

Also the link near the top: http://www.mogami.com/e/cad/wire-gauge.html

I suggest you review physics book of middle school

there you may find the formula in electricity

resistor = resistivity x length/ cross area and in thermo part find length(temp you order) = length(normal temp)x temp coefficient. ignor area chnge.

then, ohm law, enough

This site has also a lot of helpfull calculators for your question

http://www.calculatoredge.com/

What is your load and power for this?

Easy. Just look up the resistance per metre for the cable you are using .multiply by 12 to get the total resistance . Double it for two conductors.Answer Y ohms.

Multiply Y ohms by 0.5 amps. Voila.

I am an EE working as an EE,ME, Inst Eng, Constrols sys eng on power plant construction projects !!!!

best way to learn is multiple discipline.

I am trying to find the resistance per meter:

Resisitivity of copper at 25C = 1.7x10^8 Length = 12 meter Dia. = .5 @ 24 AWG

Resistance = ((16.8nano-ohms/meter)(12meter))/(pi*(.0025^2)) =

= 0.01039nano-ohms Is This Correct for the resistance of this length?

Epke that cakcukator doesnt help because the input is only 12 Volts.

This is what I dont get. If V=IR and I start with 12 V and .25 amps then the starting Resistance equals 48 ohms? what the hell does that meen?

Next calculating voltage drop. R is constant. V and I change. How do I find out how much the current changes because even if I find resisitivity it does not affect the input for the current I.

example: I find p (resisitivity) and plug it in to find Resistance. Then I plug that into Vd = I * R with R being the one I just caclulated, but why would I use the same current i started with?

Thanks.

HAHA no one is responding...

Oh well, On i go...

So CURRENT is CONSTANT!!! and Resistance is constant per foot but adds up over a few meters!!!

SO heres what I have the VD= (.25amps)(1.02ohms for 12 meters) = .256 ohms

So if I have 12 V going in i have 11.744 coming out after 12 meters!!!!!

if you have time someone check this please!

Damn.

Still doesnt make sense because what I did has nothing to do with incoming voltage and I am assuming the Voltage changes with varrying input voltages. Can anyone clarify this?

Oh sorry about that maybe this one is better

http://www.powerstream.com/Wire_Size.htm

according this site AWG24 has 25.67Ohm/1000ft

voltage drop 0.158V

voltage at end of the circuit 11.842V

According the calculator

when i calculate myself i get 11.747V

Don't forget to double the Vd to account for the neutral wire.

Chazl

Oh yeah forgot about that one iT's been a while