# Resistor replacement

#### spike1947

Joined Feb 4, 2016
167

Hi
I have a board that has 2x R220 and 1xR56 , 220ohms and 56Ohms resistors on it, I think they are rated at 1/2W , now I can only get 3W from this supplier along with other stuff, will that be ok ? .

cheers

Spike

#### dl324

Joined Mar 30, 2015
11,231
If they'll fit. You can determine wattage from the size. The only complication is that manufacturers make some "small" package resistors that dissipate twice the power of the traditional sizes.

#### spike1947

Joined Feb 4, 2016
167
If they'll fit. You can determine wattage from the size. The only complication is that manufacturers make some "small" package resistors that dissipate twice the power of the traditional sizes.
Hi
Thanks for your reply, yes I know the general size vs W , I just wanted to know if there would be a problem to fit a 3w resistor in place of a 1/2w !
Spike

#### jpanhalt

Joined Jan 18, 2008
10,068
What is the construction of the current resistors? Carbon, metal film etc. Same question for the 3W. Many higher wattage resistors (about half on Digikey) are wire wound, and depending on use, that inductance could be a factor to consider.

Do you mean 56 Ω or 560 Ω?

As for space, very definitely an issue to consider. If through hole, you can turn the bigger resistor vertically and mount like that. Like this:

#### spike1947

Joined Feb 4, 2016
167
What is the construction of the current resistors? Carbon, metal film etc. Same question for the 3W. Many higher wattage resistors (about half on Digikey) are wire wound, and depending on use, that inductance could be a factor to consider.

Do you mean 56 Ω or 560 Ω?
Yes the wording was a bit confused R56 =56 ohms= Fifty Six .

#### spike1947

Joined Feb 4, 2016
167
I think they are Carbon

#### jpanhalt

Joined Jan 18, 2008
10,068
Then use carbon.

BTW: Units that are the names of people are not capitalized when referring to the unit and used in a sentence; whereas, the label for the unit (e.g., W) is always capitalized. Poor George Ohm is denied the capital "O" as the unit for resistance, unfortunately.

#### dl324

Joined Mar 30, 2015
11,231
I just wanted to know if there would be a problem to fit a 3w resistor in place of a 1/2w !
If the resistors are of the same type, it likely wouldn't be a problem. To say with more certainty, we need to know the application.

#### spike1947

Joined Feb 4, 2016
167
If the resistors are of the same type, it likely wouldn't be a problem. To say with more certainty, we need to know the application.
Hi
Thank so for your reply , they are off a kenwood Chef A901 Food Mixer .

#### spike1947

Joined Feb 4, 2016
167

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#### dl324

Joined Mar 30, 2015
11,231
they are off a kenwood Chef A901 Food Mixer
In that case, using an over sized resistor of any type won't likely be a problem.

#### jpanhalt

Joined Jan 18, 2008
10,068
Why do you think the resistors are bad? Unless burned by over current, they are usually quite reliable.

The picture you show looks like the wire is melted, but the resister looks fine. What happened?

Last edited:

#### dl324

Joined Mar 30, 2015
11,231

#### spike1947

Joined Feb 4, 2016
167
Looks like carbon film to me.
Hi
Thanks for your reply , does it make a difference to the choice if it is carbon filter

#### WBahn

Joined Mar 31, 2012
26,047

Hi
I have a board that has 2x R220 and 1xR56 , 220ohms and 56Ohms resistors on it, I think they are rated at 1/2W , now I can only get 3W from this supplier along with other stuff, will that be ok ? .
The 56 Ω resistor you show in the picture doesn't look like 1/2 W, more probably 1/4 W, but perhaps the picture is misleading as to scale.

In general, using a higher-wattage resistor OF THE SAME KIND is not a problem provided it can physically fit in the space provided; certainly there are exceptions, but it is unlikely that a 5% tolerance resistor would be used in most such situations. For use in the application you are talking about, it is doubtful that even using a different kind of resistor would cause an issue (but we can't be sure unless we see the schematic and even then it might not be clear).

Why can't you just use another supplier? I would expect that 3 W resistors might be sufficiently more expensive that it might be worth going elsewhere. But depending on where you are located, that might not be the case or even an option.

#### spike1947

Joined Feb 4, 2016
167
The 56 Ω resistor you show in the picture doesn't look like 1/2 W, more probably 1/4 W, but perhaps the picture is misleading as to scale.

In general, using a higher-wattage resistor OF THE SAME KIND is not a problem provided it can physically fit in the space provided; certainly there are exceptions, but it is unlikely that a 5% tolerance resistor would be used in most such situations. For use in the application you are talking about, it is doubtful that even using a different kind of resistor would cause an issue (but we can't be sure unless we see the schematic and even then it might not be clear).

Why can't you just use another supplier? I would expect that 3 W resistors might be sufficiently more expensive that it might be worth going elsewhere. But depending on where you are located, that might not be the case or even an option.
Hi
Yes I think they could be 1/4W , they measure about 8.5mm length and 2.74mm thickness

#### upand_at_them

Joined May 15, 2010
458
I agree with jpanhalt. I would just solder in a new wire and leave the resistor alone.

#### dl324

Joined Mar 30, 2015
11,231
Yes I think they could be 1/4W , they measure about 8.5mm length and 2.74mm thickness
More likely to be 1/2W.

SEI carbon film resistors:

Note that the last two rows are for the "mini" resistors.

Joined Jan 15, 2015
5,604
Take this for what it's worth or not worth. Resistors just don't fail and when we see a cooked resistor what we see is generally just a symptom and not a cause. The question then begs why did a resistor have excessive current causing it to fail? Then we can add if I replace a 1/2 Watt resistor with a 3 Watt what will happen to whatever caused the initial failure? There is a very good possibility that you replace the cooked resistors and promptly have more cooked resistors.

Ron