Author Topic: Investigation on ... (Read 12704 times)

branadic · « **on:** December 02, 2016, 08:05:33 pm »

This thread is about the investigation on ...

Well, no words about it yet. It's up to your guess. Here are the first pictures of some parts a friend of mine currently fabricates for this project. The next pictures will follow soon and after a while you will get an idea of what this will end up in.

tautech · « **Reply #1 on:** December 02, 2016, 08:09:46 pm »

Waveguides ?

2N3055 · « **Reply #2 on:** December 02, 2016, 08:48:59 pm »

Either resonant cavity or oven...

Andreas · « **Reply #3 on:** December 02, 2016, 09:03:43 pm »

Hello,

looks more like one of those zero ohms resistors or a 4 wire shunt.

with best regards

Andreas

Gyro · « **Reply #4 on:** December 02, 2016, 09:04:45 pm »

Hmmm,

It's in the metrology section, high thermal mass enclosure, structurally stable..... Resistance standards? No fixing holes on the top surface though and they look finished. Something potted? Strange if so. $:-\$

Theboel · « **Reply #5 on:** December 02, 2016, 11:51:23 pm »

I bet its a resistance standard

VintageNut · « **Reply #6 on:** December 03, 2016, 02:59:08 pm »

Quote from: Theboel on December 02, 2016, 11:51:23 pm

I bet its a resistance standard

+1 Metrology individual resistors look similar to this.

TiN · « **Reply #7 on:** December 03, 2016, 05:03:27 pm »

Resistor tempco test boxes?

I'm gonna build some too, as my current TEC jig used for LTZ reference module test is just too painfully slow for TCR test.

Gyro · « **Reply #8 on:** December 03, 2016, 06:19:18 pm »

Come on branadic, give us a break - is there some kind of lid???

ManateeMafia · « **Reply #9 on:** December 03, 2016, 06:48:57 pm »

My guess is that they will laser weld the lids and install kovar leads or some hermetic connector out of the sides.

branadic · « **Reply #10 on:** December 03, 2016, 07:43:04 pm »

There is a lid on top and some feedthrough capacitors at the sides.

mimmus78 · « **Reply #11 on:** December 03, 2016, 07:48:04 pm »

Too much pieces for a simple investigation ...

Inviato dal mio Nexus 6P utilizzando Tapatalk

tatus1969 · « **Reply #12 on:** December 03, 2016, 08:19:30 pm »

~~RF directional coupler for a VNA...~~

kxenos · « **Reply #13 on:** December 03, 2016, 08:55:34 pm »

I would guess voltage reference using low noise chinese zeners or oil filled resistors

acbern · « **Reply #14 on:** December 03, 2016, 08:58:21 pm »

hermetic resistance?

manganin · « **Reply #15 on:** December 03, 2016, 09:10:27 pm »

Quote from: acbern on December 03, 2016, 08:58:21 pm

hermetic resistance?

If you look closely there seems to be a naked bulk metal foil resistor inside the box.

2N3055 · « **Reply #16 on:** December 03, 2016, 09:18:41 pm »

4w for resistor, and 2 for thermistor or RTD....
hm...

manganin · « **Reply #17 on:** December 03, 2016, 09:34:38 pm »

Worth noting that the 4-wire feedthrough for the main resistor is actually not necessary. Simply calculate how much the very short resistor copper wires affect the total temperature coefficient.

The SR104 uses 2-wire feedthrough but there is also 15 cm 2-wire cabling from the feedthrough to the binding posts (2w/4w interchangeability was important at the time it was designed).

KerryW · « **Reply #18 on:** December 03, 2016, 09:40:31 pm »

Copper chips?

TiN · « **Reply #19 on:** December 04, 2016, 04:54:16 am »

I'd buy few samples of such neat boxes for my unhappy foils

branadic · « **Reply #20 on:** December 04, 2016, 09:43:01 am »

Quote

If you look closely there seems to be a naked bulk metal foil resistor inside the box.

Good observation

Yes, it is a hermetic case for Vishay VAR resistors in 4W connection and an additional PT1000, using PCap01 a like chips to measure and digitize temperature. The case will be filled with Galden, to avoid humidity effects. The lid is soldered to the bottom part.
It's just to find out how Vishay VAR can perform. Because at the institute I work for our main topic is packaging of integrated circuits. What I've learned so far is, that every highend sensor can perform bad if package and assembly is bad. So take the naked part, use an adequate packaging technology and the part will perform much better.

Andreas · « **Reply #21 on:** December 04, 2016, 10:47:13 am »

Hello branadic,

one question arises to me.
Does Galden expand with temperature?
How is the relation of the expansion coefficient against the housing.
Or is there some pressure relief planned?

With best regards

Andreas

branadic · « **Reply #22 on:** December 04, 2016, 10:54:47 am »

I plan to use something like LS230, so no big deal within normal operation.

Theboel · « **Reply #23 on:** December 04, 2016, 11:22:59 am »

Hi Branadic.
Could you consider to use more sensor like BME280
So you can measure humidity and pressure

acbern · « **Reply #24 on:** December 04, 2016, 11:38:13 am »

why galden? just because its handy? I would think others such as fluorinert or silicone transformer oil (ok, soldering issues, but thats after the fact anyway) are more itended for that purpose, and partly also show higher insulation resistance. I do not know galden very well, other than its used for VPS, maybe you can give us some details why you selected it.


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Author Topic: Investigation on ... (Read 12704 times)

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