# 0 Ohm resistance

Discussion in 'General Electronics Chat' started by Iodem_Asakura, Nov 24, 2005.

1. ### Iodem_Asakura Thread Starter Senior Member

Sep 14, 2004
140
0
I thought that a 0 ohm resistance was used as a fuse, but i'm begining to doubt about it. Could someone light me up about this? Is it used as a fuse or a jumper? How much current does it support?

2. ### Dave Retired Moderator

Nov 17, 2003
6,960
144
You will find that a fuse actually has low resistance, which is not 0Ω. The fuse is designed as the weakest point in the circuit and will blow first if there is a current surge over the rating of the fuse. Up to the fuse rating the fuse mateial acts merely as a resistive element dispating power in the same way as resistor would.

The only example I know of with (effective) 0Ω resistance are superconductors: Information on Superconductors

3. ### kurios Member

Sep 29, 2005
14
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well according to me what i have studied and observed is that the fuse do have some resistance but not equal to 0. bcoz i it have 0 resistance then why not we use the direct wire instead of using fuse.... just think over it

secondly, the fus has some resistance but that resistance is soo much low with respect to the load resistance that it can be said as ≈ 0Ω hence the fuse blows first whenever current than the normal ratio as fuse provides the easiest path (due to it's low resistance)

4. ### Sebi Well-Known Member

Sep 24, 2005
59
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The zero ohm "resistor" (marked with one black stripe or on SMD "0") used as jumper. This method simple for automatic assembly.

5. ### Iodem_Asakura Thread Starter Senior Member

Sep 14, 2004
140
0
Thanks that was what i was talking about, the zero ohm resistor (the one marked with an only stripe of black color). Then the answer is, that it is used as a jumper, eh?

Do you know how many current does it support? I have only seen it in oine size.

6. ### rjenkins AAC Fanatic!

Nov 6, 2005
1,015
69
The type we use are rated by the manufacturer at:

25A @ 25'C linearly derated to 0A at 150'C
(These have a body 7mm long x 2.5mm diameter, lead 0.6mm diameter)

I think it's basically the rating of the wire they are moulded around..

7. ### Dave Retired Moderator

Nov 17, 2003
6,960
144
I've not come across them before.

To back up what rjenkins is saying, check here.

8. ### mozikluv AAC Fanatic!

Jan 22, 2004
1,437
1
hi

here's another info on 0 Ω links

moz

9. ### chulomex New Member

Dec 1, 2005
4
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Zero Ohms are usually used as jumpers. Sometimes there are paths that you may want to add to an already built board and you would really like to have a way to add that part of the circuit later. Then all you do is put a placeholder for the resistor but don't put anything in. When the time comes that you need to add that part of the circuit all you do is install a Zero Ohm resistor and now the other path is working as well.