Hi,
as the title says, I am looking for high precision capacitors and inductors.
I am designing a hardware module, that should be used to determine the machine capability of a system containing a pxi-based measuring card and a matrix.
For this module I need to find very stable components (capacitors and inductors). The components will only be measured with the measuring card, so they are not under load for a long time. But as uncertainty is very critical when determining the machine capability, the more stable the components are, the better.
This means a low temperature coefficient, low aging losses, etc are in need.
For capacitors:
I need components of capacitance 100 pF, 1 nF, 10 nF, 100 nF, 1 uF, 10 uF, 100 uF, 1 mF, 10 mF, 100 mF and 1 F. For the range of 100 pF to 100 nF I have decided to use NP0/C0G mlccs, but for the bigger values I’m not yet sure which capacitors offer the highest stability. Any recommendations? Please add some info if possible.
For inductors:
I need components of inductance 1 uH, 10 uH, 100 uH, 1 mH, 10 mH and 100 mH. I didn’t find much information which inductors offer high stability, therefore I could not choose any parts yet. If anyone can offer some insight and/or has recommendations, it is very much appreciated.
I know that I can’t get something as precise as this (https://de.ietlabs.com/inductance.html), but I hope there are capacitances and inductors that at least come closer to these specs.
Thanks in advance!
Cheers,
Lukas
Before you consider rolling your own they make readily available product out there for metrology/calibration laboratories called capacitance and inductance standards. Try doing a search term like ‘precision decade inductor standard’.
Hey, I’m not trying to build my own capacitance or inductance standard, but a module, that can be connected to the measuring card of the systems where machine capability needs to be proven. I tried to make that clear by linking an inductance standard by ietlabs. If it was possible, that indeed would be the easiest solution I agree.
I know that no regular component will get as precise as a capacitance or inductance standard, but I was thinking that there is something in between. For example for resistors, I am using ones by Vishay Precision Group. And now I’m searching something similar for capacitors and inductors. Hope that clears thing up
As mentioned before, these components generally exist on a quantity-quality spectrum; the larger the L or C value, the less stable that value is likely to be because of the techniques needed in order to obtain those L or C values in a practical device size.
Polypropylene film capacitors are likely to be among the most stable high-value capacitors broadly available, with temperature sensitivities on the order of 200PPM/°C. As for inductors I suspect that something in a toroid form would be preferable, but temperature sensitivities are generally much poorer and long-term behaviors not as well characterized. The properties of magnetic core materials also tend to have significant and non-linear frequency dependance, complicating matters if one’s idea of precision also includes stability over a significant range of test frequencies.
Large-value, high -stability reactive components are not a common item; precision resistors have utility in strain gauge and similar applications (no surprise then that VPG makes both) but outside of the sort of reference standards referred to, I’m not aware of any supplier of reactive components in 100mX territory that characterize devices to similar (or even close) levels of precision as the VPG resistive products.
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