Multimeter measuring resistors wrong (2)

Thread Starter

Bert_K

Joined Jun 22, 2024
1
Actually I encounter the same problem with my OWON 18B multimeter. Today a package of components arrived with no labels. I need to measure the resistors myself. I can't get any valid data. The meter eighter counts all the way back to zero, or measures mego ohms or ohms. I havent used it much, the battery is new, and its advertized at Amazon as high value :(

Moderator edit: New thread created from this.
 

Tonyr1084

Joined Sep 24, 2015
8,015
Three things:
First, welcome to AAC.
Second, it's recommended you start a new thread.
Third, if you can show us a picture of your meter, it's probably something either in the way you've set it up or perhaps the meter is defective.

Ideally you want to use the two most right holes. The right most is the positive and the next, marked COM is the common or negative test point. Then you want to set it to read ohms. That would be two clicks clockwise from the off position, the one with the diode and ohms symbol. Forgive me if I'm speaking like you don't know what you're doing. I'm not making that assumption; but from time to time we do get people here who don't know what they're doing. Please take no offense.
Screenshot 2024-06-22 at 6.06.35 PM.pngScreenshot 2024-06-22 at 6.08.54 PM.png
 

BobTPH

Joined Jun 5, 2013
9,342
Notice that the same switch setting is used for resistance, diode check and continuity. Set the range selector switch that range then look for an Ω icon in the display. If it is the diode are the sound icon, as on the range switch, push select until you see the Ω icon. Now you are measuring resistance.
 

dl324

Joined Mar 30, 2015
17,228
I havent used it much, the battery is new
New to you? New with the meter? Have you measured the battery with a tester? Unloaded voltage can give some indication of remaining capacity, but it still isn't very meaningful.
its advertized at Amazon as high value
That means nothing on Amazon. I've purchased fake product on from some disreputable sellers.
 

MisterBill2

Joined Jan 23, 2018
19,630
Measuring resistors can cause problems. I once had to use a resistor assortment sorted by a color blind tech who used a meter. He marked the drawers with the measured values. There was no "10K"spot, only 9.7k. none of the standard values. It was tedious to use even after a year.
 

Tonyr1084

Joined Sep 24, 2015
8,015
I'm color blind. Light yellow and light green are nearly indistinguishable to me. Red and green (not light green) can run together. Blue and purple were horrible. I had to study the blue. If I saw red in it I knew it was purple. No red - it was blue. Usually. And yet I made a career in electronics. Then they came out with numbered resistors. WHAT A GOD SEND that was. A 1202 was 12KΩ. Didn't have to think about it. My solution most often was plenty of light and plenty of magnification. That was usually the best way I could distinguish red from brown. Orange was easy. Grey and white were also easy. Black was a no brainer. Unless the manufacturer was running low on black and it ended up looking more like grey than anything else. But a RED GREY GREY just didn't seem like a legitimate value.

Measuring resistors in circuit doesn't work. There are other parts of the circuit affecting the reading. You always have to take a resistor out of the circuit to get an accurate reading. Then, what is it? 20%? 10%? 5%? 2%? 1%? Sometimes gold wasn't always easy to tell. Tan ? ? ? Forget about it! And I have no idea what Mauve or Fuchsia is. Didn't even know how to spell it. And Peach is a fruit.
 

Tonyr1084

Joined Sep 24, 2015
8,015
Fifth day since this thread opened and no response from the thread starter (TS). Did you get it figured out? Have we scared you away? Did we make you feel less intelligent? Please don't hesitate to respond. We feel good when we can help others.
 

sparky 1

Joined Nov 3, 2018
799
Assuming that the voltmeter and it's battery is working, ohms law should agree
with voltage across resistor for a fixed current.

If a battery measures about 1.51Vdc (see the schematic below)
so that a 1.5k Ohm resistor limits the current to 1mA
The voltage across the 10 Ohm resistor must be 10mV
If you swap R2 for R3 ( that is, interchanging R2 and R3 )
the voltage across R3 is 1.5Vdc
Good precision resistor divider calculator is helpful.
Voltage Divider Calculator - Engineering Calculators & Tools (allaboutcircuits.com)

Having a 2.5Vref and these 1% resistors on hand is helpful: 2.5k, 1.5k, 10, 1, 0.1, 0.01, 0.001Ω

Screenshot battery 10 ohm 1mA.png
 
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