problems measuring capacitors

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Othello

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I need help measuring capacitors.
I use a "Almost all digital Electronics" L/C meter to check the values of capacitors.
I recently ordered some tantalum 6.8mF capacitors which give me a value of about 0.2 mF when measured.
A second batch I got gave similar values.

Electrolytic capacitors are way off.

I wonder if rather than bad capacitors I do have a lack of understanding about the nature of capacitors, and which ones should check out ok and which ones do not.

Any clarification is appreciated

Uwe
 
Do you mean 6.8 microfarads, or 6.8 millifarads? In either case, the **broken link removed** says that the maximum range on the LC meter is 1.5 microfarads (uF).
 
Roff said:
Do you mean 6.8 microfarads, or 6.8 millifarads? In either case, the **broken link removed** says that the maximum range on the LC meter is 1.5 microfarads (uF).
Click to expand...

and non-polarized. John
 
c-meter

Hi Uwe,

look up https://www.elektor.de. Search "Messen und Testen". From the list select L-C-T-Messer.

This device measures temperatures in the range from -55 to 125deg/C with 0.5deg resolution, inductances in the range from 100nH to 100mH and capacitances in the range of 1pF to 160.000uF.

The MCU used is an Atmel ATMEga48.

The built in C-meters in DMMs do not consider the ESR of a cap, so the result will always be miles off. They are just good enough to measure if the cap has a short.

Hans
 
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I wonder why people are reluctant to use mF, but 2200uF, 4700uF instead of 2.2mF and 4.7mF.

But we have no problem using mH, mA, milliOhm, mV. Perhaps it is easily confused with nF during printing or photocopying.

I guest the "2200" or "4700" also gives the impression that it is big, which it is in physical size.
 
eblc1388 said:
I wonder why people are reluctant to use mF, but 2200uF, 4700uF instead of 2.2mF and 4.7mF.
Click to expand...

Because it causes confusion, with some people incorrectly using 'm' for micro, using a 'u' for the greek letter mu makes far more sense.

Bear in mind it's also common to say 1000pF or even 22,000pF rather than use nF.
 
nF seems to be a more recently used measurement . Older schematics seem to aviod it and only use pF and :mu:F so 1nF would be written as 1000pF or 0.001:mu:F.
 
Hero999 said:
Older schematics seem to aviod it and only use pF and :mu:F so 1nF would be written as 1000pF or 0.001:mu:F.
Click to expand...

That's funny, the older schematics I remember all used uufd (as in micromicrofarad)

Nano just seems to be a relatively recent (last 25 years) multiplier. We also used to use mu, which was written with a "mu" instead of a "u" and pronounced "millimicron," in wavelength measurements to represent what today is nm. John
 
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