The suggestion that the smaller values are more critical is true. The large capacitors can vary by a greater value and still function as they should. The smaller capacitors may be un a tuned circuit, and they may be more critical of being true to their value. I bought the U1272A today, and the U34461A a few days ago. I love them both. Great product.
Yes...I'm intrigued to understand the mechanics of how a multimeter actually does the measurement so I'll play with a few bits to suss it out and post.
If you are in repair business it means a lot. For example I come across capacitor that measure 930uf (1000uf value) and that was the only defective part in the circuit. Not always and not everybody we have ESR meter available. We just have to get use to the Agilent with information in mind that it may readd less of the actual value.
In terms of discharging the capacitor...it did cross my mind and I did it once before doing the video but did not see any difference in the reading..but there may be a better way of doing it. I tried to find how a multimeter measures a capacitor but did not find anything in my quick search. I assume it would discharge and then change taking the reading...but I'm guessing.
In each MEASUREMENT Brymen BM867 was closest to the cap figure. The measurement was recorded 3 times and then averaged out - the process was slow but most accurate. What do you think?
Probably due to different measurement frequencies or techniques. Most capacitors, especially electrolyics have some frequency vs. capacitance relationship. It's too bad you don't have an LCR meter to explore that further, I don't think multimeters often specify the way they measure caps.
Iam not sure at what dial setting your putting the meter at, when testing the capacitor. Iam using a craftman meter at work at this time, not really happy with it. Iam a high reach mechanic and run into a lot of electrical issues on the machines. I really want an realiable meter, I like the fluke. Thank you KEEP UP THE GREAT WORK!
I know this is an old video, but have you tried to messeure how many Hz each multimeter uses when testing caps? Some test by about 8-9 Hz while other test with i.e. 100 Hz or 120 Hz and that will give wary different results.
Well, that looks like a crappy capacitor. The Panasonic and Nichicon ones I regularly buy are usually within 50uF of the value (>=1500uF) ... measuring with a Uni-T UT61E which has about 0.5-1% error though. One thing I noticed is you don't discharge the capacitor between measurements. AFAIK some discharge the capacitor up to a threshold, then pump energy into them - threshold could be different between meters. Do you think that could affect measurements?
I have a Fluke 87 which displays the "OL" reading when I attempt to test capacitance. I have tried it on old and new caps of various sizes. Any ideas....Thanks in advance.
My pleasure, thanks for the feedback.
I am pretty sure that you should discharge capacitor through the resistor, before measuring with the next multimeter.
nel
Yup, I had the same thought..
The suggestion that the smaller values are more critical is true. The large capacitors can vary by a greater value and still function as they should. The smaller capacitors may be un a tuned circuit, and they may be more critical of being true to their value. I bought the U1272A today, and the U34461A a few days ago. I love them both. Great product.
But, what is the reference? why you didn't use a capacimeter to know what capacitance value is the correct?
Yes, I'm keen to understanding how a multimeter gets to a capacitance reading. I'll do some digging and post.
@mjlorton LCR meters use something like 1VAC in the 1 to 100kHz range for testing caps. Attach your scope while testing and let's see!
Yes...I'm intrigued to understand the mechanics of how a multimeter actually does the measurement so I'll play with a few bits to suss it out and post.
If you are in repair business it means a lot. For example I come across capacitor that measure 930uf (1000uf value) and that was the only defective part in the circuit. Not always and not everybody we have ESR meter available.
We just have to get use to the Agilent with information in mind that it may readd less of the actual value.
In terms of discharging the capacitor...it did cross my mind and I did it once before doing the video but did not see any difference in the reading..but there may be a better way of doing it. I tried to find how a multimeter measures a capacitor but did not find anything in my quick search. I assume it would discharge and then change taking the reading...but I'm guessing.
btw it might be interesting to measure what voltage they charge them to. maybe lyt caps respond differently depending on voltage
In each MEASUREMENT Brymen BM867 was closest to the cap figure. The measurement was recorded 3 times and then averaged out - the process was slow but most accurate. What do you think?
Probably due to different measurement frequencies or techniques. Most capacitors, especially electrolyics have some frequency vs. capacitance relationship. It's too bad you don't have an LCR meter to explore that further, I don't think multimeters often specify the way they measure caps.
Iam not sure at what dial setting your putting the meter at, when testing the capacitor. Iam using a craftman meter at work at this time, not really happy with it. Iam a high reach mechanic and run into a lot of electrical issues on the machines. I really want an realiable meter, I like the fluke. Thank you KEEP UP THE GREAT WORK!
Actually just checked the manual, it's 4% +5 counts accuracy over 22uF, 3% + 5 under. It's a 22k count meter.
Nice video. It does have me wondering is it or isn't it a esr capable meter
I know this is an old video, but have you tried to messeure how many Hz each multimeter uses when testing caps?
Some test by about 8-9 Hz while other test with i.e. 100 Hz or 120 Hz and that will give wary different results.
Well, that looks like a crappy capacitor.
The Panasonic and Nichicon ones I regularly buy are usually within 50uF of the value (>=1500uF) ... measuring with a Uni-T UT61E which has about 0.5-1% error though.
One thing I noticed is you don't discharge the capacitor between measurements. AFAIK some discharge the capacitor up to a threshold, then pump energy into them - threshold could be different between meters. Do you think that could affect measurements?
After factoring in the plus and minus on their specifications, which dmm is closest to the value of the capacitors tested?
I have a Fluke 87 which displays the "OL" reading when I attempt to test capacitance. I have tried it on old and new caps of various sizes. Any ideas....Thanks in advance.
I am really enjoy your tutorials, but i wont to ask a bout 2.8" LCD Digital Multimeter ExCEL DT9502A, if I can use it to test capacitance?.
Fluke Wins !!!
If you are dealing with new capacitors with known good ESR than capacitor value will not make such difference in the circuit.
interesting but then the question is, which one was right : )