MPX(MRH) resistors

[shodan@micron]

void

[bsw_m]

Microwire in glass insulation. Photos in bright and dark field. Sorry for low quality of photo, i do this by my phone trough eyepiece. Resistor is 100KOhm MRH.

[Vgkid]

Thanks for posting that. Reminds me of how glass fibers are made(fiber optics)

[manganin]

Made in: PO "Microprovod" (Kishinev, Moldova, USSR) RIP!

Company out of business? What happened and when?

[daqq]

Sorry for offtopic, the idea of glass coated microwires that actually bend is just so cool I had to look it up. There are companies that make them and one has an interesting video of how they are actually made:

https://www.rvmagnetics.com/production

That's so cool!

[daqq]

Question: Would a wire coated in glass not have insanely low current leakage? Like better than PTFE of the same size?

[Kleinstein]

Glass is not such a great insulator. PTFE tends to have better volume values, though it is hard to measure and compare. It still depends on the composition of the glass - there are many different glasses. PTFE can also vary, depending on chain lenght and density.
An interesting point with the glass insulation is, that there is a direct interface and thus possibly low triboelectric effect. However the very thin wire may not be that great for longer distance anyway.

On the downside, some glasses react to humidity, especially as such a thin layer, and there may this be some slow humidity effect. So it is a good thing the resistors have the extra hermetic seal.

[3roomlab]

any idea of past/current data about its drift per year character?

[bsw_m]

any idea of past/current data about its drift per year character?

I'm don't have data for one year stability (drift). But may be these info helps:

1. I have some boxes with 100MΩ MRH resistor in NOS condition. This resistors was manufactured in 1992y. Tolerance for this resistors is 0.1%. But my resistors have an actual error in the range of -0.04 ... -0.06%, this is after 29years of mfg. date 
But at the same time, I want to draw your attention to the fact that the official datasheet for these resistors speaks of a maximum resistance of 20MΩ, while my resistors have a nominal value of 100MΩ, perhaps they were made by special request. I can also say that I have a certain number of MPX resistors for non-standard values (300MΩ ... 500MΩ), they all have an error of <0.1%
2. In contrast, I can say that I had heard a lot of feedback that MPX Series resistors in fairly high quantities drifted far beyond its specifications.