Re: One giga ohms resistor

On 19 Nov 2005 01:15:21 -0800, "mowhoong@xxxxxxxxxxx"
<mowhoong@xxxxxxxxxxx> wrote:

>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
.

Relevant Pages

  • Re: One giga ohms resistor
    ... >>I am wondering what is the pupose to use such a high resistance ... >>person know the reason for buying a 1 giga ohm resistor? ... Professional Circuit Designer ...
    (sci.electronics.basics)
  • Re: One giga ohms resistor
    ... >person know the reason for buying a 1 giga ohm resistor? ... They are used as feedback resistors in photodiode transimpedance ... Steve Noll | The Used Equipment Dealer Directory: ...
    (sci.electronics.basics)
  • Re: build circuit
    ... >>I want to build a simple circuit that will turn off a 120 volt light ... 1Meg Ohm resistor ... Solder the 0.33uF capacitor between these leads. ... Connect the ground lead to ground (ie, the center pin of the LM7805, which is also connected to the - input of the wall adapter). ...
    (sci.electronics.basics)
  • Re: Einsteins Doppler equation wrong?
    ... the voltage is zero, i.e dE/dt is at its greatest, and ceases when the ... short circuit. ... :>: consisted of a connector with a small resistor tying the core ... :>: Without the terminator, the thinnet cable spits back echoes into ...
    (sci.physics.relativity)
  • Re: Some Notes on Gary =?iso-8859-1?Q?Pimm=92s?= Phono Preamp
    ... Follower as the input amp. ... The 47 K input resistor forms part of the playback correction curve in ... this case an actual circuit needs to be posted as proof. ... So then what is your explanation for the rectifiers used in this phono preamp? ...
    (rec.audio.tubes)