Resistor value question

edelgiud

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So in the attached picture, on the left is a red red brown resistor and on the 2k setting on my ohm metre it measures .222.
On the right (pulled out of circuit to be sure) this seems to be a red red gold resistor, which my understanding is 2.2 ohm resistor, but it measures 4.7 on the 200 setting of my ohm meter. There's a second one on the board which measures the same so is my photograph showing me the wrong color or is it completely out of spec here and I should replace them?

Thanks.
 

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RED RED BROWN GOLD is 220ohm 5%.

For a FOUR BAND resistor, use this ->

20240906135056006.png

Use GOOGLE to see that resistors can have between 3-6 color bands. (SEARCH: "resistor color code" and images)
 
Here is a better picture another place on the board. The one on the left again measures 4.7 ohm
Not the same as the 220 ohm with the brown band on the right.

Thanks.
 

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So the GOLD GOLD would be 2.2ohm.

Are you measuring out-of-circuit?
Which PCB is this? Don't you have a schematic?

You should also get a better "auto ranging" DMM. :)
 
Yes, as specified in my initial post, I pulled the other one out of circuit.
No, it's not a schematic that anybody has. It's a old custom board.
 
Auto-Range DMM: no I shouldn't be getting one of those. I like to learn things the hard way. When I was in university over 30 years ago, every kid in my engineering class with a little cash had one of those fine HP calculators. I did the work by hand and I graduated with 95% in all my math classes :)
 
Do an experiment.
Take your "manual" DMM and short the test leads together.
What reading do you get? :unsure:
In the 200 scale, I see 3.3 so I guess it's bad? In the 2K scale I see .003.

Suggestion for a new digital multimeter for average old hobby will now be considered then, lol.

Thanks.
 
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It's a 2.2ohm 5% resister.

If you add in the small error of your meter leads, you get 5.5ohms.
I think you're fine. Standard meters are not perfectly accurate at such small resistances.
 
So that's solves it.
When measuring low impedances, you have to take into consideration the impedance of your test leads and the inaccuracy of your meter.
Don't cheap out on test equipment. It's a waste of time an effort for everyone. LOL

For LCR meters, you can calibrate the unit by shorting the leads and the machine then provides a more accurate reading.
But DMM, aren't so sophisticated.
 
So that's solves it.
When measuring low impedances, you have to take into consideration the impedance of your test leads and the inaccuracy of your meter.
Don't cheap out on test equipment. It's a waste of time an effort for everyone. LOL

For LCR meters, you can calibrate the unit by shorting the leads and the machine then provides a more accurate reading.
But DMM, aren't so sophisticated.
I'll take your suggestion if you see anything decent on amazon.ca (or eBay located in Canada) for a new DMM. Thanks.
 
I'm a big fan of FLUKE DMM. But they're pricey.

Recently, I've been playing with a new hybrid unit from FNIRSI - the new 2C53T- has 50MHz scope and DMM and function generator. And does XY mode.
I got mine with a pre-order and coupon off of AliExpress a few months ago.

818kXZSJqQL._SL1500_.jpg

But for $38CAD (w/ coupon), cheaper than a visit to McDonalds, this 6000 count unit on amazon.ca has good reviews (>4.5 * with 22000 comments), good features and specs. For this little cash, you probably can't go wrong. :)

811eJXZKKmL._SL1500_.jpg


Search KLOV, that there's many other comments on "cheap but arcade worthy" DMM.
 
If you want a good cheap meter, the UNI-T UT58D or UT58E are good ones. I have both. They should run you somewhere in the $50-60 range.

You can also google them, and see that they are recommended by others as well. (There was a good eevblog forum thread about them, last I looked.)
 
I'm a big fan of FLUKE DMM. But they're pricey.

Recently, I've been playing with a new hybrid unit from FNIRSI - the new 2C53T- has 50MHz scope and DMM and function generator. And does XY mode.
I got mine with a pre-order and coupon off of AliExpress a few months ago.

View attachment 805544

But for $38CAD (w/ coupon), cheaper than a visit to McDonalds, this 6000 count unit on amazon.ca has good reviews (>4.5 * with 22000 comments), good features and specs. For this little cash, you probably can't go wrong. :)

View attachment 805545


Search KLOV, that there's many other comments on "cheap but arcade worthy" DMM.
lol on the cheaper than McDonald's comment!
OK, I'm intrigued by that hybrid DMM/scope. Maybe that's a good buy for me to upgrade my testing tools. Thanks.
 
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Whatever you do, don't search " UT58D or UT58E " on amazon.ca ... the prices are crazy 3x-5x higher than noted above. And they aren't even auto-ranging. WTF? :(

For reference -> (free ship, no tax, two probes and case included) $120CAD for the 2C53T full option version
(I paid >12% less; try to find a coupon).


 
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