50G ohm Retirement Fund

[pguerra75]

I was recently cleaning up shop in an electronics warehouse and came across an interesting find. A plastic bottle of approx. 26000 loose 50g Ohm 30% resistors (0805) package. I did some research and the cheapest I can find these things is around $2 at volume. So essentially I found $52000 worth of parts that almost no one will want. One can only laugh. 

Just thought this crowd might enjoy that.

[alm]

I wonder what kind of PCB cleaning you would need to keep parallel leakage down for such a small package. Put guard traces around the pads? Mill a narrow slot under the resistor?

[Benta]

A plastic bottle of approx. 26000 loose 50g Ohm 30% resistors (0805) package.

Rattling around in a bottle, you can be pretty certain that they are not 50 Gohm anymore.

[Codebird]

I can't imagine what anyone would even want with such a part.

[Benta]

I can't imagine what anyone would even want with such a part.

Yes, the customer base is limited, to say the least. Not where I'd put my retirement fund.

[ZeTeX]

Pictures?

[jpanhalt]

List them on eBay as "vintage."  What have you got to lose?

[TerraHertz]

Huh, that's amusing. Since I need some 10G and 20G surface mount resistors.
Too bad paralleling them up probably won't work so well, since the surface leakage would be additive, cleaning more difficult, and greater overall parasitic capacitance.

For why I need some, see https://www.eevblog.com/forum/repair/restoring-a-mass-spectrometer-maybe/

Anyway how much for about 100 of them? (And are you aware you shouldn't handle them with bare fingers?)

[pguerra75]

Anyway how much for about 100 of them?

Not gonna charge anyone do to the fact I don't know their history. PM me your address and I'll ship them over, and yes I am aware

Pictures?

List them on eBay as "vintage."  What have you got to lose?

Haha, I should list them individually, haha.

[pguerra75]

I can't imagine what anyone would even want with such a part.

Nor can I but I am a bit of an impostor EE.

[raspberrypi]

I was recently cleaning up shop in an electronics warehouse and came across an interesting find. A plastic bottle of approx. 26000 loose 50g Ohm 30% resistors (0805) package. I did some research and the cheapest I can find these things is around $2 at volume. So essentially I found $52000 worth of parts that almost no one will want. One can only laugh. 

Just thought this crowd might enjoy that.

How did you figure out the quantity? Weight?

[pguerra75]

   How did you figure out the quantity? Weight?

I had a local jewler weigh a sample of 100 and then the lot.

[MarkS]

50G Ohm? 50 giga-Ohm?

[Bryan]

For what application what would a 50Gohm resistor be used for?

[boffin]

You sure they're not caps?
I say that due to the colour, sort of a yellowish which is pretty common with ceramic caps.

[nitro2k01]

If you have nothing better to do, hook up say 100 of them in parallel and see if it checks out to about 500M, which would be a more easily measurable value. Or hook up a few of them in parallel and see if they measure as a capacitors I guess. I have a hard time seeing where something like a 50G ohm resistor in such a small package would be useful. Maybe in something that is potted, but then again just the resin would probably contribute a not insignificant stray resistance. So hmm...

Would love to see a "teardown" of it though. Maybe polishing one layer at a time off of it to reveal its internal structure. Maybe send the whole bag, or a carefully selected sample, to mikeselectricstuff?

[AndyC_772]

Factory rejects. They were supposed to be 10k, but someone forgot to apply the metal film and just left the ceramic substrate. 

[Alex Nikitin]

For what application what would a 50Gohm resistor be used for?

Electrometers. At work I routinely use 20G and  100G resistors and plan to use SMD parts of these values in a near future. The application in my case is Quadrupole Mass Spectrometry. Similar electrometers are used in many other applications where very small charges/currents have to be measured or sensed. The current noise level is reduced with the increase in the resistor value, so larger the value, lower the noise (but slower the response due to a parasitic capacitance). 20G resistor has about 1fA RMS self-noise in 1Hz BW. 50G resistor - about 0.6fA.

I can also add that it is perfectly possible to use SMD parts with these values. If somebody would like to know the details, than the ADA4530-1 datasheet, evaluation board description and AN-1373 application note can provide a good starting point.

Cheers

Alex

[tszaboo]

You sure they're not caps?
I say that due to the colour, sort of a yellowish which is pretty common with ceramic caps.

Preatty much, what I would have said. 50Gohm on a pcb in a 0805 package is a part not soldered in...

[alm]

Well, 50 GOhm resistors do exist in 0805 (up to 100 GOhm in that series). Make sure you do not exceed that 1/8 W power rating .

[tggzzz]

Well, 50 GOhm resistors do exist in 0805 (up to 100 GOhm in that series). Make sure you do not exceed that 1/8 W power rating .

... especially when staying within the max voltage rating!

[pguerra75]

You sure they're not caps?
I say that due to the colour, sort of a yellowish which is pretty common with ceramic caps.

Yup, verified it all with test equipment.

[pguerra75]

Just head an Idea, who things I should glitter bomb Dave with 26k SMD resistors?   

[rsjsouza]

pguerra75, if it is not inconvenient for you I would have some use for a portion of these resistors. I sent you a PM yesterday.

[Cerebus]

For what application what would a 50Gohm resistor be used for?

Feedback resistor in a transconductance amplifier for measuring nano/picoamps. One of these would give you 0-5V out for an input current of 0-100 pA.