Continue to Site

# maximum available resistor value in the market

Status
Not open for further replies.

#### Junus2012

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

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....

... resistor should be at least of 10 * 50 M Ohm = 500 M ohm or greater.

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

Junus2012

### Junus2012

Points: 2
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.

Junus2012

### Junus2012

Points: 2
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

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

- - - 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 ???

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.

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

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.

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'.

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 ???

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

Junus2012

### Junus2012

Points: 2
Thank you,

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

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

They have many values, not all, but many. Its good to see detailed catalog or ask them for specific value.

Junus2012

### Junus2012

Points: 2
Thank you very much

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

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.

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)
Of course. We used Victoreen glassed resistors, about a hundred years ago. Now the company doesn't exist any more :-(

CRHV2512 is 50 G Ohm, Wow
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 ...

Junus2012

### Junus2012

Points: 2
Thanks a lot Erikl

Of course. We used Victoreen glassed resistors, about a hundred years ago. Now the company doesn't exist any more :-(

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 ...

Status
Not open for further replies.