1 - 10 of 10 Posts

#### ohmer

·
##### Registered
Joined
·
14 Posts
Discussion Starter · ·
Hi, I have a question from a customer that I do not know right off hand. I am an aircraft electrician, and don't know the answers right off hand. Anyones help would be greatly appreciated. Thanks in advance and here is what they wrote:
I need to find the resistance of a circuit with the following information:

120volt circuit delivers 350 watts of power and another 10 watts of power are consumed by the circuit. There is no ground fault.

How much current is carried by the hot wire?
How much current is carried by the neutral?
How much current is carried by the grounding conductor?
What is the resistance of the circuit?

Thanks for the help! I don't want to over-due a circuit and have lots of problems!!!

#### 480sparky

·
##### I own stock in FotoMat!
Joined
·
39,115 Posts
Hi, I have a question from a customer that I do not know right off hand. I am an aircraft electrician, and don't know the answers right off hand. Anyones help would be greatly appreciated. Thanks in advance and here is what they wrote:

I=P/E
I=360 watts/120 volts
I=3 amps for both the hot and neutral. With no ground fault, there is 0 ohms on the ground.​

R=E/I
R=120 volts/3 amps
R=40 ohms​

#### ohmer

·
##### Registered
Joined
·
14 Posts
Discussion Starter · ·
Wow, now I feel silly. I just wasn't looking at it this way. Thanks very much.

I=P/E
I=360 watts/120 volts
I=3 amps for both the hot and neutral. With no ground fault, there is 0 ohms on the ground.​

R=E/I
R=120 volts/3 amps

R=40 ohms​

#### randomkiller

·
##### R.I.P. 2014
Joined
·
4,722 Posts
And another one bites the dust.

#### tripbraker

·
##### Registered
Joined
·
12 Posts
the wonderful powerwheel

#### Rong

·
##### IBEW Local 661 JW
Joined
·
228 Posts
Hi, I have a question from a customer that I do not know right off hand. I am an aircraft electrician, and don't know the answers right off hand. Anyones help would be greatly appreciated. Thanks in advance and here is what they wrote:

Learn to fix stuff...www.ohmcheck.com for electrical troubleshooting and how-to .

Does this question and with this tag line scare anybody else????

#### randomkiller

·
##### R.I.P. 2014
Joined
·
4,722 Posts
Learn to fix stuff...www.ohmcheck.com for electrical troubleshooting and how-to .

Does this question and with this tag line scare anybody else????
Changes the perspective a tad, huh?

#### waco

·
##### Registered
Joined
·
1,966 Posts
A circuit "delivers" 350 watts? A circuit can supply voltage and it can "deliver" current, but the two work together to generate watts.

So, a 120 volt circuit drawing 3 amps produces 350 watts, but what is the other ten watts about?

Does the question mean the load uses 340 watts and 10 watts are line losses (I square R losses as we used to say?) If so, then the circuit resistance and the load are in series. Total current is still 2.917 amps, but the circuit resistance is found by dividing the square of 2.917 amps into 10 watts.

1.175 Ohms.

#### John Valdes

·
##### Super Moderator
Retired
Joined
·
18,216 Posts
Anyone know where I can find a letter size ohms law circle. My vision is not what it used to be. So a nice big one right here on my wall would be great. I would be glad to print it out from a web site if someone knows where. I can find only small ones, like the ones above.

#### randomkiller

·
##### R.I.P. 2014
Joined
·
4,722 Posts
Anyone know where I can find a letter size ohms law circle. My vision is not what it used to be. So a nice big one right here on my wall would be great. I would be glad to print it out from a web site if someone knows where. I can find only small ones, like the ones above.
Try printing these out and blowing them up a tad:

http://www.getahelmet.com/jeeps/tech/ohm/ohmslaw.gif