Current sensing and standard resistor

  • #1
I have a 12v switching transformer; one of the legs on a black brown silver gold 2w resistor is broken off. I have had zero luck finding a standard .01 2w resistor. I did find a current sensing resistor at the values, but should it be used. The resistor in the power supply is ceramic, I think, and bluish silver in color. Looks like the ones you would find in electronics store on the shelf but just not in .01.lol I took some EE in collage but only remember enough to be dangerous. Just wanted to be honest.
Thanks Brandon
 

Answers and Replies

  • #3
309
1
I doubt your resistor is 0.01 ohms.

Check again using this calculator

http://www.csgnetwork.com/resistcolcalc.html
That calculator doesn't have all the color bands for the multiplier. Here's a better image: http://www.google.com/imgres?imgurl...=X&ei=S7GHTdvGA4HerAHttuyzBg&ved=0CB4Q9QEwAA".

If it is a current sensing resistor, the resistance should be really small.

Are you sure the color code is black-brown-silver? Not not brown-black-silver (which would be 0.1 ohms, not 0.01 ohms).

If th current sensing resistor you have is the same resistance value as the one that broke, the only think that matters is how much current it needs to handle. A .01 ohm 2 W resistor can handle 14 A of current. Is your other resistor rating for that much?
 
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  • #4
5,441
9
the resistance should be really small.

(Really) small yes, 10 milliohms, no. That is the sort of resistance of a soldered joint so would be a waste of time for any soldered in component.

If 10 milliohms was necessary in the circuit it would most likely be formed from a carefully sized pcb track.
 
  • #5
It is black brown silver gold. I will check the specs on other resistor. My local distributor has access to five resistor manufacturer , and not a one offer. 01 ohm 2watt. Smallest I could find is .1 ohm 2watt. I guess I could parallel a bunch of .1 but don't have the space.
 
  • #6
The power supply is a 12-15vdc 15amp. We use them to power battery chargers and tire truer. I race 1/12 scale RC cars. The tire lathe is to cut down foam tires to achieve proper roll out.
 

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