87V wacky capacitance reading

[supermattch]

Hi everyone.

I have a 87v that is acting up. So when I try tk test capacitance of a capacitor for example pne stamped 103, it should read 10nF or somewhere around there. Well I measured countless 103 capacitors and it always gives readings of 16+ nF. To make matters worse, when I hit rel, the 103 capacitors reads OL for all of them. Is my 87v broken?

Someone please help me make sense of this situation and to pursue the right way to fix my meter. Thank you.

[NE666]

I think the bottom line is, without another reference or transfer standard (i.e. another capacitance meter of known good calibration, or capacitor of known value) on hand, you can't be certain where the issue lays. Particularly if these 'countless' 103 capacitors are all from the same source/batch - they could all be out of spec, or at least, have a very broad tolerance.

Also, just to be clear, when you are activating the relative measurement mode you do have the probes shorted together first? And how are you probing? It makes a difference. Do you have a tweezer type probe, or are you trying to make good contact with surface mount components using regular probes? Are you measuring them in, or out of circuit?

If it were me, I'd acquire some known good, 'low' tolerance film capacitors (1%) from the likes of Digikey or Mouser, in a range of values across the measuring range(s) of your multimeter, and test those. Use through hole components, as they are far easier to make a good connection with, using probe leads with croc clips.

Obviously, this doesn't constitute anything like a proper, full calibration, but it is a good sanity check.

[Martin72]

In addition, a multimeter of this type is not really designed to measure such small capacitances accurately.
The Fluke87V will measure capacitances with DC, via R-C.

[coromonadalix]

grab yourself an lcr meter .... i never thrust any dmm, as written they work  on RC timing  ..

[Bud]

Are you using REL button/procedure properly?

[shabaz]

10nF is large enough that you ought to get a reasonable measurement.

I set my Fluke 87V to 100nF manual range, zero'd the display using the REL button (otherwise it showed 0.3 nF) and then measured a 10nF Vishay axial MLCC to be 10.6 nF. Then I tried a 4.7 nF ceramic disc capacitor (from the low-cost Velleman ceramic capacitor kit - it's really nice), and it measured as 5.0 nF. If you're using a random Amazon/AliExpress kit then all bets are off regarding what you're actually measuring.

Make sure you're not touching the probe or component ends because that will throw off the measurement. But agree with others that this is really a job for a LCR meter (or simply buy known parts from a distributor, so there's not as many circumstances where you need to verify).

I cannot recall the last time I ever used the capacitance range on the Fluke 87V (I don't turn on an LCR meter all too often either, but can imagine other engineers may need to do that depending on their job/task specifics).

[gamalot]

In addition, a multimeter of this type is not really designed to measure such small capacitances accurately.
The Fluke87V will measure capacitances with DC, via R-C.

It's true that multimeters like the 87V aren't great for accurately measuring small capacitors, but for rough checks around 10nF, they're totally fine.

I measured a 10nF metallized polypropylene capacitor. On my Fluke 83V, the reading was between 10.19nF and 10.20nF, on my LCR meter, it came out to around 10.194nF at 1kHz.

[Psi]

First thing
- Make sure you are not touching the terminals.

Second thing
- Try some different meter probes

Third thing
- Try take the reading with the meter display backlight on and confirm the same reading, this just rules out a battery issue. That shouldn't cause a reading to change on a Fluke meter, but worth a check.

[tautech]

Hi everyone.

I have a 87v that is acting up. So when I try tk test capacitance of a capacitor for example pne stamped 103, it should read 10nF or somewhere around there. Well I measured countless 103 capacitors and it always gives readings of 16+ nF. To make matters worse, when I hit rel, the 103 capacitors reads OL for all of them. Is my 87v broken?

Someone please help me make sense of this situation and to pursue the right way to fix my meter. Thank you.

Do yourself a favor and get some LCR tweezers, I recommend the Shannon Smart Tweezers ST42.

[BeBuLamar]

If you determine that your meter is defective then send it to Fluke for repair. They should fix it for free.

[BeBuLamar]

If the capacitance is 10nF the specs of the 87V is 1% +2 digit so it should not show more than 11nF

[tooki]

Well, remember that many capacitors are ±20%, so 8-12nF for a 10nf, ±1% for the meter gives 7.92-12.12, and then we add the ±2 counts in 100nF range in 4.5 digit mode means 007.90nF to 012.14nF.

[Fungus]

To make matters worse, when I hit rel, the 103 capacitors reads OL for all of them. Is my 87v broken?

When you press REL the meter goes into manual ranging mode. Make sure the range it locks into can measure 10nF.

[BeBuLamar]

Well, remember that many capacitors are ±20%, so 8-12nF for a 10nf, ±1% for the meter gives 7.92-12.12, and then we add the ±2 counts in 100nF range in 4.5 digit mode means 007.90nF to 012.14nF.

Even then it's not near 16nF that the OP got. Something is wrong with the meter. I would send fo Fluke and see what they say.

[Martin72]

I would like to see how the OP measured the capacities, using pictures.

If the capacitance is 10nF the specs of the 87V is 1% +2 digit so it should not show more than 11nF

It would be great if the entire measuring range were within this tolerance.
That would render almost all dedicated LCR measuring devices obsolete.
As I said, I would be interested in seeing pictures of the measurements, as well as the type of capacitor that was measured.

[dkarst]

It seems a bit premature to send meter back to Fluke.  I would suggest borrow a meter from someone to verify the reading or try to measure a different known good part.  I just had a moment but found a partial spool of old coax (RG-59, about 250 -300') in my shop.  My 87V correctly read 5.6 nF for this which is the expected ~ 16-20pF/ft.  I nulled out the 0.3nF as mentioned above.  Make sure to separate the leads physically so they don't contribute much to stray capacitance.  I would try to find a little larger value cap if you have one.