I have a burned out big blueish gray resistor (probably a 1/2 or 1 watt) that I'm trying to find the value of but there is a mysterious black band at the end of the resistor where the tolerance band would be but obviously the tolerance/failure rate/temperature band cannot be black. What does it mean?

4.6mm x 15.5mm

I have confirmed colors:

Brown Black Gold Gold Black

So I think it's safe to say it's a 1 ohm, 5% tolerance. But what is that last black band!? It's driving me insane.

enter image description here

  • 3
    \$\begingroup\$ Do you mean the left resistor in your picture? If so I think the second band is black, and the final band is paler. Hard to say what colour though - maybe silver? \$\endgroup\$
    – Jack B
    Commented Sep 19, 2017 at 23:03
  • 6
    \$\begingroup\$ grey grey grey grey = burnt \$\endgroup\$ Commented Sep 19, 2017 at 23:11
  • 1
    \$\begingroup\$ The markings on the right-hand resistor are burned beyond recognition in that photo (although in some cases it might be possible to read something after cleaning). Therefore you seem to be asking about the left-hand resistor, to try to find the value of the right-hand resistor. Are you sure they were the same value? In other words: How does it help, to find the value of the left-hand resistor? If you really want to know that, you could desolder it and measure. Also note that the reason for the right-hand resistor overheating, was probably a component failure elsewhere in the circuit. \$\endgroup\$
    – SamGibson
    Commented Sep 19, 2017 at 23:19
  • \$\begingroup\$ Yes I'm referring to the left one. There are two parallel AC legs so I'm assuming they are the same (crossing fingers) I'm no engineer. \$\endgroup\$
    – naps1saps
    Commented Sep 20, 2017 at 0:12

2 Answers 2



  • brown =1
  • black =0
  • gold = x 0.1
  • gold = 5%
  • black = non-inductive (bifilar wound WW)

is a 10x0.01= 1.0 Ohm 5% WW resistor.

enter image description here

If 0.9mm body length then 1W , if more then 2 or more.

The tempco is used by some non-wirewound types and black would be 300 ppm or the highest for non WW. rated tempco. If yours is non wire wound bet this.


enter image description here

While I’m at this again, get flame-proof if you like.

You can decide best on the colours that make sense from this example chart.

  • 2
    \$\begingroup\$ The resistors are probably Ok but the epoxy case transistor exploded \$\endgroup\$ Commented Sep 20, 2017 at 0:02
  • \$\begingroup\$ Did you mean if the body width in the middle is 0.9mm? Do you think that last band is silver? I was thinking the middle ones were gold but couldn't find any evidence it could be gold ROFL. BTW it was measuring about 1.5-1.2Ohm so I believe your answer is correct. I will try to source this part and mark it answered when I do. \$\endgroup\$
    – naps1saps
    Commented Sep 20, 2017 at 0:15
  • \$\begingroup\$ That box is the main power-on relay and seems to be working as it should. \$\endgroup\$
    – naps1saps
    Commented Sep 20, 2017 at 0:17
  • \$\begingroup\$ I've updated the picture. That last band is black after all. So what does that change? \$\endgroup\$
    – naps1saps
    Commented Sep 20, 2017 at 4:07
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    \$\begingroup\$ @quetzalcoatl probably not after 3 yrs. anyways all leads have inductance starting around ~ 0.5nH/mm , so as the R get's smaller the gauge must get higher so the length of the twists in my answer (which is the part with no inductance and resistance >> length of the untwisted wire leads. \$\endgroup\$ Commented Mar 9, 2021 at 13:40

Check this, It seems to be the resistor you're looking for.


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    \$\begingroup\$ Which says "1 Ohms ±5% 1W". You should at a minimum state that in your answer. Otherwise it is just a link-only answer (which may be deleted at any time). \$\endgroup\$ Commented Jan 7, 2018 at 17:51
  • \$\begingroup\$ We don't do link-only answers here. \$\endgroup\$ Commented Jan 7, 2018 at 19:24
  • \$\begingroup\$ @OlinLathrop I wonder why not for good sites. These are often saved in Wayback archive.org Oli :) \$\endgroup\$ Commented Mar 9, 2021 at 13:43

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