Testing my cheap ohmmeter

[Geo-TH,In]

This is the best ohmmeter I own.
Accurate within 1 percent

 

[MarkB_MI]

Time to stir the pot, George?
Is that a one percent resistor? If so, then you can't prove the meter is accurate to one percent. Back in the day when I worked with automated test equipment, we always used a minimum 3:1 accuracy ratio between the measurement we were making and the instruments and/or standards we were using to make the measurement. So in your case, I would want the resistor to be accurate to at least 0.3 percent.

 

[Geo-TH,In]

Time to stir the pot, George?
Is that a one percent resistor? If so, then you can't prove the meter is accurate to one percent. Back in the day when I worked with automated test equipment, we always used a minimum 3:1 accuracy ratio between the measurement we were making and the instruments and/or standards we were using to make the measurement. So in your case, I would want the resistor to be accurate to at least 0.3 percent.

This was supposed to be a precision resistor from a scientific supplier used in a Wheatstone Bridge.
My meter is still the best one I've ever used.

 

[olddavid]

What does it read when you short the leads together. Subtract that reading from the reading you are showing. That should be closer to the actual resistance of your "resistance standard" coil. At any rate the reading is "close enough for government work" as we used to say.

 

[Hemmjo]

Not AT ALL trying to be disrespectful here. If you are asking of your meter is close enough, and do understand the implications of being off by only 0.7 ohms, your meter it just fine for your needs. That amount of error can be from the wires, the test probe tips, the contacts on the resistor. etc. That error is insignificant unless you are working on some VERY HIGH END electronics.

 

[Geo-TH,In]

What does it read when you short the leads together. Subtract that reading from the reading you are showing. That should be closer to the actual resistance of your "resistance standard" coil. At any rate the reading is "close enough for government work" as we used to say.

Close enough for my work

 

[Geo-TH,In]

Close enough for my work View attachment 5192

 

[Geo-TH,In]

 

[Geo-TH,In]

HF metrr

 

[Geo-TH,In]

HF meter

 

[John T]

For any meter, especially a Harbor Freight, and if that's a quality precision resistor with an actual 100 OHMS ?????, thats sure close enough for most what anyone would ever need. Id not hesitate to use or rely on it for old tractor use where we DO NOT NEED perfect accuracy. Of course if accuracy and precision were necessary and at stake (probably not for your or my old car and tractor use) then Id opt for a more expensive meter such as a Fluke.

Its been my experience with a wide assortment and brands of meters both cheap and expensive over many years ITS THE EXTREME LOW OHMS where a cheap meter is less accurate then say a Fluke.

I say for your use and accuracy that meter is just fine GO FOR IT no problem in my opinion. I have several older cheap meters laying around also lol

Congrats and thanks for the report, thats a good enough meter and adequate accuracy in that range of higher ohms assuming the resistor is actually 100 ohms !!!!!!!!!!!!!!

John T

 

[GermantownGreen]

This is the best ohmmeter I own.
Accurate within 1 percent

Thanks for sharing this, Geo,
We got one of those for Bailey, our 19 yr old, for Christmas.
We've used it twice.
I need to readup on the instructions. It's way over my head...
GG Wes

 

[MarkB_MI]

For any meter, especially a Harbor Freight, and if that's a quality precision resistor with an actual 100 OHMS ?????, thats sure close enough for most what anyone would ever need. Id not hesitate to use or rely on it for old tractor use where we DO NOT NEED perfect accuracy. Of course if accuracy and precision were necessary and at stake (probably not for your or my old car and tractor use) then Id opt for a more expensive meter such as a Fluke.

Its been my experience with a wide assortment and brands of meters both cheap and expensive over many years ITS THE EXTREME LOW OHMS where a cheap meter is less accurate then say a Fluke.

I say for your use and accuracy that meter is just fine GO FOR IT no problem in my opinion. I have several older cheap meters laying around also lol

Congrats and thanks for the report, thats a good enough meter and adequate accuracy in that range of higher ohms assuming the resistor is actually 100 ohms !!!!!!!!!!!!!!

John T

Its been my experience with a wide assortment and brands of meters both cheap and expensive over many years ITS THE EXTREME LOW OHMS where a cheap meter is less accurate then say a Fluke.

John, I wouldn't try to make a fractional ohm measurement with any two-wire meter, including my beloved Fluke. For that you need a meter with four-wire (source + sense) capability. Those meters can accurately measure a few milliohms.

 

[John T]

John, I wouldn't try to make a fractional ohm measurement with any two-wire meter, including my beloved Fluke. For that you need a meter with four-wire (source + sense) capability. Those meters can accurately measure a few milliohms.

For sure when it comes to very very low resistances a two wire meter isn’t going to do the job but for non critical farm and old tractor use George’s HF is good enough. As I experienced at very low resistances any super cheap meter lacks accuracy while a better quality such as a Fluke is better Things may have changed since but that was what I found.

 

[John T]

For sure when it comes to very very low resistances a two wire meter isn’t going to do the job but for non critical farm and old tractor use George’s HF is good enough. As I experienced at very low resistances any super cheap meter lacks accuracy while a better quality such as a Fluke is better Things may have changed since but that was what I found.

These arent cheap https://www.camiresearch.com/Campaigns/Web-Articles/4-wire-testing.html

 

[MarkB_MI]

These arent cheap https://www.camiresearch.com/Campaigns/Web-Articles/4-wire-testing.html

Well, I think to get four-wire you have to go to a benchtop multimeter, and those tend to be pricey. I did find one handheld multimeter with four-wire, but it's 1700 bucks!

GMC Metrahit 27M

 

[Geo-TH,In]

Well, I think to get four-wire you have to go to a benchtop multimeter, and those tend to be pricey. I did find one handheld multimeter with four-wire, but it's 1700 bucks!

GMC Metrahit 27M

Mark.
You know I'm cheap, This meter is under $40.
No way I'll spend big bucks on a 4 wire ohmmeter.
The average guy on YT may use an ohmmeter to measure a ballast resistor.
Think about this, is the accuracy of the meter that critical when shopping for a ballast resistor?
I say NO, because all you need to know is the ballast resistor has the same resistance as the coil?
Lets say your meter is off my one ohm. Your meter says your coil resistance is 5 ohms when it's 4 ohms.
Does it matter? NO. As long as your new ballast shows 5 ohms the same as your coil.

Bottom line, How important is the accuracy of any ohmmeter when working on a 75 year old tractor?

 

[Jim.ME]

Mark.
You know I'm cheap, This meter is under $40.
No way I'll spend big bucks on a 4 wire ohmmeter.
The average guy on YT may use an ohm meter to measure a ballast resistor.
Think about this, is the accuracy of the meter that critical when shopping for a ballast resistor?
I say NO, because all you need to know is the ballast resistor has the same resistance as the coil?
Lets say your meter is off my one ohm. Your meter says your coil is 5 ohms when it's 4 ohms.
Does it matter? As long as your new ballast shows 5 ohms the same as your coil.

Bottom line, How important is the accuracy of any ohmmeter when working on a 75 year old tractor?

I understand and accept you are free to check all this out. However, if that is the bottom line, why have you spent so much time on this?

I guess I have been lucky over my 50+ years. When I've needed a ballast resistor I went to a parts store and bought one, put it on (without checking the ohms), and run it. I don't remember ever having one burn up points or having unusual ignition problems after a new one was installed.

 

[Hobo,NC]

This is the best ohmmeter I own.
Accurate within 1 percent View attachment 5177

Come on Geo lets get on with the program : )

 

[Geo-TH,In]

Come on Geo lets get on with the program : )

HoBo
You failed to remember, I'M CHEAP. I carry these 3 meters in my truck. Each meter has a special purpose.