Electronics > Metrology

DIY 10K low TC home lab referance

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kj7e:
I put together a simple yet very stable, low TC home lab 10K reference just for the heck of it.  The centerpiece is a Vishay VHP101 oil filled hermetically sealed 0.005% tolerance part - Y407810K0000V9L.  While this is no replacement for a real secondary standard with a linear TC and predictable drift, this will make a nice cost effective reference to use around the shop with more than acceptable performance.  The case is a small but heavy duty (thick wall) plastic Hammond box with a copper EMI/RFI inner coating - 1594RBBK.  The thought here was to provide a slight amount of thermal stability at the same time as provide a guard path around the resistor.  The posts are Pomoa 3770's for the 4W and 3760 for the guard.  The only down side with the plastic case is the binding posts can be forced to apply mechanical stress on the leads to the resistor, I tried to add some strain relief on the leads.  Most of the time I will be using a shielded 4w lead with spades, so binding post stress should not be a big issue.

A few days ago I did a TC sweep and comparison to a Visahy Z201 (10K, 0.005%), I was impressed with the results;


Z201:     18-28C = 0.8ppm/C.    10-40C = 0.7ppm/C.
VHP101: 18-28C = 0.05ppm/C.  10-40C = 0.05ppm/C.

Anyway, if your like me you rather look at the photos than read about it;




CalMachine:
Lookin good!!   :-+ :-DMM

hwj-d:
 :-+


--- Quote ---The only down side with the plastic case is the binding posts can be forced to apply mechanical stress on the leads to the resistor, I tried to add some strain relief on the leads.
--- End quote ---

Maybe an inner steel plate with flattened holes, like the molds from the Pomona plastic bushings?

kj7e:

--- Quote from: hwj-d on May 17, 2018, 11:46:33 pm --- :-+


--- Quote ---The only down side with the plastic case is the binding posts can be forced to apply mechanical stress on the leads to the resistor, I tried to add some strain relief on the leads.
--- End quote ---

Maybe an inner steel plate with flattened holes, like the molds from the Pomona plastic bushings?

--- End quote ---

I actually thought about doing just that, but after it was assembled.

GEOelectronics:
That fancy copper lined case probably cost more than the die-cast aluminum ones I use for everything.

Nice project. Thanks for showing pictures. One day I'll be able to make charts like that but not yet.

Respectfully,
George Dowell

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