EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: heathkitman on May 26, 2013, 10:42:15 pm
-
Is there such a thing as a precision capacitor?
I want to get a capacitor to use as a standard with my capacitance meters to check for accuracy and drift over time. What type of capacitor is the most precise / stable over time? I intend on using something in the 1.0 µF range.
Thanks
-
Yes, there are standard capacitors. They are very expensive if you want them new. Used ones from General radio or HP are affortable and rather stable.
But it depends on your capacitance meters what you need. For some ebay special everything will work as long as it is within 1% or so. If you want to check a GR-1620 it will be a whole different story.
What meter, 3 or 4 terminal ?
What range, do you need pF or uF
Air capacitors are very stable, polyprop and mica too.
My oldest ones are air capacitors from Philips and from the 30's. They are still very accurate although the two terminal connection makes it useless for calibration. ( 100-1000 pF)
I have a HP decade that does 40pF to 1.1uF, that are mica and air caps. This is a three terminal and usable for normal LCR meters
For calibration I also have a GR standard capacitor that does 1 to 10 uF in steps of 1 uF. Has thee terminal connection.
But I have a GR1620 and I used that to make a collection of standard caps ranging 1pF to 100pF with 6 digit resolution, some nF values and some uF values. I measured them also on some calibrated good quality (non-Chinese) LCR meters. So these are good enough for calibrating or checking handheld LCR meters. Made them from PCB, used micas and some (not used) high quality ceramics I got from some one and were made for high precision RF circuits
http://www.pa4tim.nl/?p=3418 (http://www.pa4tim.nl/?p=3418) GR
(http://www.pa4tim.nl/wp-content/uploads/2011/04/hp440bcap.jpg)
(http://www.pa4tim.nl/wp-content/uploads/2011/04/hp440bbinnen.jpg)
http://www.pa4tim.nl/wp-content/uploads/2010/11/standaardcondensator.jpg (http://www.pa4tim.nl/wp-content/uploads/2010/11/standaardcondensator.jpg) one of the Philips
-
Is there such a thing as a precision capacitor?
I want to get a capacitor to use as a standard with my capacitance meters to check for accuracy and drift over time. What type of capacitor is the most precise / stable over time? I intend on using something in the 1.0 µF range.
Thanks
I got couple of these 0.5uF caps recently from seller on ebay who sells old Russian stock
http://www.ebay.com/itm/0-2uF-0-5-250V-Precision-Polystyrene-Capacitors-2pcs-/200845492287?pt=LH_DefaultDomain_0&hash=item2ec353003f (http://www.ebay.com/itm/0-2uF-0-5-250V-Precision-Polystyrene-Capacitors-2pcs-/200845492287?pt=LH_DefaultDomain_0&hash=item2ec353003f)
0.5% is pretty good for capacitors. They are bigger than they look on photo, but both were within 0.1% at room temperature according to my LCR meter (Agilent).
Same seller has more nominations.
??? in Russian means microfarad, and "," (comma) is used for decimal point.
-Alexei.
-
Is there such a thing as a precision capacitor?
I want to get a capacitor to use as a standard with my capacitance meters to check for accuracy and drift over time. What type of capacitor is the most precise / stable over time? I intend on using something in the 1.0 µF range.
Thanks
yeah i bought 4 different types of 0.1% caps for $10 each on ebay not to long ago from 100pf to 0.47u ... but be careful the leads, close metal and even small changes in temperature can throw off the measuring of meters ... with just 2 terminals use short, spaced out leads and use the same leads to test them all!