maximum available resistor value in the market

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Junus2012

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hello

I am constructing a measurement setup for simulating OTA. the simulated output impedance is 50 M Ohm, thus in order to characterise my circuit without degrading the voltage gain of the OTA, then need a resistor should be at leastof 10 * 50 M Ohm = 500 M ohm or greater.l

I dont know if such a great single resistor is available or not , or what is the maximum available resistor so I could connect the extra in parallel.

Thank you very mucch

- - - Updated - - -

Note: the resistor I need is low power resistor
 

what is the precision that you need for this resistor ? 5% ? 1% ?

Note that even a normal PCB on FR4 material will have less resistance than this....
 

any one of them or even more, no problem for me

Thank you very much


kripacharya said:
what is the precision that you need for this resistor ? 5% ? 1% ?

Note that even a normal PCB on FR4 material will have less resistance than this....
Click to expand...
 

Junus2012 said:
... resistor should be at least of 10 * 50 M Ohm = 500 M ohm or greater.
Click to expand...

What about a sub-threshold 1nA constant-current (CC) source? Its resistance is high enough - and can easily be calculated.
 
Erikl, from the principle of load, this is possible and a new thing for me to know, however, normal resistors help me more because if for example I would test the OTA in the inverting setup, with resistor I can control the gain (R2/R1) but with the current supply I cant

Thank you

erikl said:
What about a sub-threshold 1nA constant-current (CC) source? Its resistance is high enough - and can easily be calculated.
Click to expand...

- - - Updated - - -

Oh my ***

CRHV2512 is 50 G Ohm, Wow

but please it is written in the data sheet range from 12 M to 50 M ohm, what means of a range in a constant resistor ???

tpetar said:
Check this :

1206 50MΩ
https://uk.farnell.com/vishay-techno/crhv1206af50m0fkft/resistor-50mr-1206-hi-v/dp/1572806RL



Datasheet
https://www.farnell.com/datasheets/1640465.pdf

Check in datasheet there is greater resistors.
Click to expand...
 


If you just need a measurement by simulation, you don't need a real resistor device, you can use any virtual resistor from your analog lib.
 

;-) of course i will do this if i am simulating, but want it for real measurement setup

Thank you any way

erikl said:
If you just need a measurement by simulation, you don't need a real resistor device, you can use any virtual resistor from your analog lib.
Click to expand...
 

Several websites are run by electronics hobbyists and engineers, where you can purchase components from a list of a few items. I once purchased 50 Meg and 100 Meg resistors from such a website.

Similar parts are available on Ebay.
This link does a search on '(50, 100, 200, 500) meg ohm resistor'.
 

Junus2012 said:
Oh my ***

CRHV2512 is 50 G Ohm, Wow

but please it is written in the data sheet range from 12 M to 50 M ohm, what means of a range in a constant resistor ???
Click to expand...

Ranges are linked with particular resistor manufacturing serie. They make fixed value from that range for that resistor serie.
 
Thank you,

Do I need to request them or it is available in all the values in the range ?

tpetar said:
Ranges are linked with particular resistor manufacturing serie. They make fixed value from that range for that resistor serie.
Click to expand...
 

Referring to the original question, I don't think that you actually need a high-ohmic resistor to determine your OTA parameters. I presume there are several more intelligent methods.
 

Hello FvM

it is easy to construct the PCB un-expensive setup with the resistors, however I am also interest to know these method you want to tell, please

FvM said:
Referring to the original question, I don't think that you actually need a high-ohmic resistor to determine your OTA parameters. I presume there are several more intelligent methods.
Click to expand...
 

Junus2012 said:
Erikl ... however, normal resistors help me more because if for example I would test the OTA in the inverting setup, with resistor I can control the gain (R2/R1)
Click to expand...
Of course. We used Victoreen glassed resistors, about a hundred years ago. Now the company doesn't exist any more :-(

Junus2012 said:
CRHV2512 is 50 G Ohm, Wow
Click to expand...
But here you can still buy them, up to 450MΩ, and cheaper than those offered @ eBay.

We had to mount them on teflon bearings and wash them with alcohol to keep their high resistance ...
 
Thanks a lot Erikl



 

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