One giga ohms resistor

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A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?
Best Wishes and merry x'mas
regards

 

[Rheilly Phoull]

A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?
Best Wishes and merry x'mas
regards

Perhaps they are making the worlds highest voltage 'Phase pencil' ??

 

[Paul Burridge]

A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?

The very high input impedance of MOSFET stages often specify these
very high value bias resistors, IIRC. Helps to prevent loading down
previous hi-output impedance stages.

 

[Bob Masta]

A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?
Best Wishes and merry x'mas
regards

I've seen very high resistors used as feedback in
sensitive photodetector and electrometer-type circuits.
Biggest I ever used was 100 Meg, and even at that
it was non-trivial to actually get the resistance you
paid for. The problem is that it doesn't take much
leakage current to knock down these high values
in the actual circuit. You need to be fanatical about
cleaning the outside of the glass resistor body (these
are always in glass bodies), since any sort of film
will cause leakage. You need may exotic circuit board
and teflon mounts, etc, etc. And it's hard to know
when things have gone wrong, since you typically
don't have a femtovolt or picocandela calibration source!
<g>

Best regards...


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

 

[Michael A. Terrell]

A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?
Best Wishes and merry x'mas
regards

I remember seeing them in some early B&W Vidicon type TV cameras.

 

[John Fields]

A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?

---
I've used them as part of the feedback voltage divider in regulated
high voltage power supplies.


----+---->10KV OUT
|
[1GR]
|
1V<---+
|
[100K]
|
GND

 

[John Fields]

I've seen very high resistors used as feedback in
sensitive photodetector and electrometer-type circuits.
Biggest I ever used was 100 Meg, and even at that
it was non-trivial to actually get the resistance you
paid for. The problem is that it doesn't take much
leakage current to knock down these high values
in the actual circuit. You need to be fanatical about
cleaning the outside of the glass resistor body (these
are always in glass bodies),

 

[Steve Noll]

A customer next to me asking the shop assistant whether he sells one
giga ohm resistor.
I am wondering what is the pupose to use such a high resistance
component, this is almost
a good insulator for any material like plastic. Dear member, does any
person know the reason for buying a 1 giga ohm resistor?
Best Wishes and merry x'mas
regards

They are used as feedback resistors in photodiode transimpedance
amplifiers (current to voltage converters.) One nanoamp into an op
amp with a 1 G feedback resistor comes out as one volt.

I Gigohm's are even available in chip form and in 1% tolerance. I
have used as high as 10 Gigohm 1% resistors in photodiode test
equipment. Victoreen, now owned by Ohmite, is one manufacturer.
Digi-Key carries them through 5 gig 1%.

Steve Noll | The Used Equipment Dealer Directory:
| http://www.big-list.com
| Peltier Information Directory:
| http://www.peltier-info.com

 

[redbelly]

They are used as feedback resistors in photodiode transimpedance
amplifiers (current to voltage converters.) One nanoamp into an op
amp with a 1 G feedback resistor comes out as one volt.

Or, I imagine, any application where small currents (as low as several
pA) are to be measured.

Mark