High Voltage Resistors

[Palinurus]

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

 

[Guy Macon]

Palinurus <trinitite@ev1.net> says...

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

Yes. a series string of lower resistance and lower voltage resistors.

 

[Palinurus]

Guy Macon wrote:

Palinurus <trinitite@ev1.net> says...

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?


Yes. a series string of lower resistance and lower voltage resistors.

An obvious idea. Now take your calculator and figure out just how many
10M resistors I'd have to maze up to get 10G. I'm already using that
scheme to get some lower values. I'm trying to avoid the madness of
tedium and lead fumes, as well as a ridiculously large package. But
thanks for trying.

 

[Hal Murray]

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
....

Yes. a series string of lower resistance and lower voltage resistors.

How big a string will that take?

A quick poke at Digikey shows that the biggest value they have
for 1206 at 1% is 10M. So the OP would need 100 in series to
get to 1G and 1000 to get to 10G.

Doesn't seem to practical. (But might avoid the min order
quantity problems.

--
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other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited
commercial e-mail to my suespammers.org address or any of my other addresses.
These are my opinions, not necessarily my employer's. I hate spam.

 

[Guy Macon]

Palinurus <trinitite@ev1.net> says...

An obvious idea. Now take your calculator and figure out just how many
10M resistors I'd have to maze up to get 10G.

Not willing to search and find 500M resistors? Oh well. Let us know
if you solve your problem within the constraints you have chosen.

 

[Hal Murray]

Not willing to search and find 500M resistors? Oh well. Let us know
if you solve your problem within the constraints you have chosen.

Thanks for the prod.

Digikey stocks 1,000M resistors. Ohmite Mini-Mox.
$15 each for 1/4W. $5 for 1.5W.
(maybe that price is for some other version)
1/4W is good for 500V. 1/2W is good for 1000V.

Data sheet says some versions go up to 1,000G but
Digikey doesn't stock them.

There is also a Maxi-Mox and Slim-Mox vesions.

--
The suespammers.org mail server is located in California. So are all my
other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited
commercial e-mail to my suespammers.org address or any of my other addresses.
These are my opinions, not necessarily my employer's. I hate spam.

 

[Leon Heller]

"Palinurus" <trinitite@ev1.net> wrote in message
news:10lcklvc6bnaa20@corp.supernews.com...

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order and
millennial lead time. In exchange for these unheard-of concessions, I am
willing to pay a moderately extortionate price. Does anyone know of a
source for such things?

Caddock specialises in that sort of thing:
http://www.caddock.com/Online_catalog/high_voltage/high_voltage.html

They go up to 10G, 1% or .1%.

Leon

 

[John Fields]

On Sun, 26 Sep 2004 00:25:39 -0500, Palinurus <trinitite@ev1.net>
wrote:

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

---
Try Vishay-Dale. They have an extensive line and lots of disty, so
you might get lucky.

--
John Fields

 

[Palinurus]

John Fields wrote:

On Sun, 26 Sep 2004 00:25:39 -0500, Palinurus <trinitite@ev1.net
wrote:


I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?


---
Try Vishay-Dale. They have an extensive line and lots of disty, so
you might get lucky.

Their TR10 series was one I was looking at, but finding someone who

actually stocks the requisite values is hard. I've been given a solution
to the 1G problem, but if I can avoid spending $50 for the 10G, that
would certainly be a consideration.

 

[Guy Macon]

Palinurus <trinitite@ev1.net> says...

Robert Baer wrote:

Palinurus wrote:

Guy Macon wrote:

Palinurus <trinitite@ev1.net> says...

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

Yes. a series string of lower resistance and lower voltage resistors.

An obvious idea. Now take your calculator and figure out just how many
10M resistors I'd have to maze up to get 10G. I'm already using that
scheme to get some lower values. I'm trying to avoid the madness of
tedium and lead fumes, as well as a ridiculously large package. But
thanks for trying.

Mouser carries Ohmite metal oxide HV resistors: axial to 1000Megs 1%
@5KV (588-MOX series) and planar to 1500Megs 1% @20KV (588-SM series).
Strangely, the planars are also cheaper (page 404 catalog 619).

Seems Mouser hase something closer to your requirements.

Their SM106031007 is good enough. Don't know how I overlooked it. Thanks.

I was expecting another "Here is my advice"/"Your advice is shit"/"*plonk*"
discussion and was pleasantly surprised when the conversation turned to
an actual discussion about electronics. Did I switch newsgroups without
noticing it? <grin>

 

[normanstrong]

"Palinurus" <trinitite@ev1.net> wrote in message
news:10lcklvc6bnaa20@corp.supernews.com...

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for
something
that's actually in stock, without a special order, large minimum
order
and millennial lead time. In exchange for these unheard-of
concessions,
I am willing to pay a moderately extortionate price. Does anyone
know of
a source for such things?

Are there any temperature or humidity specifications?
Can you draw any additional current from the source (for guarding,
etc.)?
Is the 1% tolerance an actual requirement, or just for ratio purposes?
Is there a voltage coefficient of resistance requirement. i.e. does
the resistance have to be the same
at all voltages?

Can you give us an idea of the application? Is this for a regulated
power supply?

Norm Strong

 

[Palinurus]

normanstrong wrote:

Are there any temperature or humidity specifications?
Not really. Room temp, <60% RH.
Can you draw any additional current from the source (for guarding,
etc.)?
No.
Is the 1% tolerance an actual requirement, or just for ratio purposes?
An actual requirement.
Is there a voltage coefficient of resistance requirement. i.e. does
the resistance have to be the same
at all voltages?
=1ppm/V

Can you give us an idea of the application? Is this for a regulated
power supply?
It's for a gadget to test megohmmeters. Not laboratory grade. Say, if

you wanted to be sure that this:
http://www.measurebetter.com/products/aemc5100.htm
was reading properly.

>

 

[legg]

On Sun, 26 Sep 2004 00:25:39 -0500, Palinurus <trinitite@ev1.net>
wrote:

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

The only thing in my junk box over 1G is made by Welwyn

http://www.welwyn-tt.com/pdf/datasheet/3810.PDF

These tend to have ratings of 1Kv or less, so you'd have to biuld up
for 5KV anyways.

RL

 

[Robert Baer]

Palinurus wrote:

normanstrong wrote:


Are there any temperature or humidity specifications?
Not really. Room temp, <60% RH.
Can you draw any additional current from the source (for guarding,
etc.)?
No.
Is the 1% tolerance an actual requirement, or just for ratio purposes?
An actual requirement.
Is there a voltage coefficient of resistance requirement. i.e. does
the resistance have to be the same
at all voltages?
=1ppm/V

Can you give us an idea of the application? Is this for a regulated
power supply?
It's for a gadget to test megohmmeters. Not laboratory grade. Say, if
you wanted to be sure that this:
http://www.measurebetter.com/products/aemc5100.htm
was reading properly.

3 million *milli* ohms??? (they use lower case "m" which according to
standards, means "milli")
Rather low!
OTH, if they mean Megohms, then that is translated "up to 3*10^12
ohms" which is not too bad.

 

[Robert Baer]

legg wrote:

On Sun, 26 Sep 2004 00:25:39 -0500, Palinurus <trinitite@ev1.net
wrote:

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

The only thing in my junk box over 1G is made by Welwyn

http://www.welwyn-tt.com/pdf/datasheet/3810.PDF

These tend to have ratings of 1Kv or less, so you'd have to biuld up
for 5KV anyways.

RL

Resistors that are a lot larger than the Sunshine meter can handle!!!

 

[Ken Smith]

In article <10lcklvc6bnaa20@corp.supernews.com>,
Palinurus <trinitite@ev1.net> wrote:

I am in need of a few resistors, of 1 GOhm and 10 GOhm values, 1%
tolerance or better to 10 kV or better. I'm also looking for something
that's actually in stock, without a special order, large minimum order
and millennial lead time. In exchange for these unheard-of concessions,
I am willing to pay a moderately extortionate price. Does anyone know of
a source for such things?

I think www.resistor.com or "State of The Art Components" may have what
you need. I know they have 1000V parts.


--
--
kensmith@rahul.net forging knowledge

 

[Palinurus]

Robert Baer wrote:

It's for a gadget to test megohmmeters. Not laboratory grade. Say, if
you wanted to be sure that this:
http://www.measurebetter.com/products/aemc5100.htm
was reading properly.



3 million *milli* ohms??? (they use lower case "m" which according to
standards, means "milli")
Rather low!
OTH, if they mean Megohms, then that is translated "up to 3*10^12
ohms" which is not too bad.

Heh. Just shows, once again, the differences between Sales and Engineering.

 

[Ross Herbert]

On Sun, 26 Sep 2004 15:26:35 -0500, Palinurus <trinitite@ev1.net>
wrote:

|normanstrong wrote:
|
|>
|> Are there any temperature or humidity specifications?
|Not really. Room temp, <60% RH.
|> Can you draw any additional current from the source (for guarding,
|> etc.)?
|No.
|> Is the 1% tolerance an actual requirement, or just for ratio purposes?
|An actual requirement.
|> Is there a voltage coefficient of resistance requirement. i.e. does
|> the resistance have to be the same
|> at all voltages?
|<=1ppm/V
|>
|> Can you give us an idea of the application? Is this for a regulated
|> power supply?
|It's for a gadget to test megohmmeters. Not laboratory grade. Say, if
|you wanted to be sure that this:
|http://www.measurebetter.com/products/aemc5100.htm
|was reading properly.
|
|>


I would be suspicious of the specs in this table.

Under Ranges it says 30 - 30,000 milli-Ohms which means 0.030 - 30
ohms, and 3 - 3,000 GOhms ??? (that's awfully high)

Under Resistance Range it says 10 - 30,000 KOhms which is 10 - 30
MOhms, somewhat shy of the 3,000 GOhms mentioned earlier.

For a start, it would not be possible for any field service test
instrument to be capable of actually measuring in the GOhm range with
any degree of reliability and repeatability. For starters, the
moisture content of the air resting on the probe tips would give a
reading without them even being in contact with any item being
measured.

I think the real maximum range is actually 30 MOhms so that is all you
would need to verify under calibration.

 

[Ross Herbert]

Sorry, from the url given I didn't see that it was an insulation test
instrument. In that case the 30GOhms range would be relevant but I
don't see how it could be reliably calibrated except under vaccuum
conditions.

Obviously, you want to build a relatively simple test jig for
calibration purposes but even if you did manage that would your device
be acceptable to the agencies responsible for instrument calibration
Standards?

You would rerally need to use an instrument such as this
http://www.dunhaminstruments.com.au/pdf/5069v3.pdf



Mon, 27 Sep 2004 02:32:07 GMT, Ross Herbert
<rherber1SPAMEX@bigpond.net.au> wrote:

|On Sun, 26 Sep 2004 15:26:35 -0500, Palinurus <trinitite@ev1.net>
|wrote:
|
||normanstrong wrote:
||
||>
||> Are there any temperature or humidity specifications?
||Not really. Room temp, <60% RH.
||> Can you draw any additional current from the source (for guarding,
||> etc.)?
||No.
||> Is the 1% tolerance an actual requirement, or just for ratio purposes?
||An actual requirement.
||> Is there a voltage coefficient of resistance requirement. i.e. does
||> the resistance have to be the same
||> at all voltages?
||<=1ppm/V
||>
||> Can you give us an idea of the application? Is this for a regulated
||> power supply?
||It's for a gadget to test megohmmeters. Not laboratory grade. Say, if
||you wanted to be sure that this:
||http://www.measurebetter.com/products/aemc5100.htm
||was reading properly.
||
||>
|
|
|I would be suspicious of the specs in this table.
|
|Under Ranges it says 30 - 30,000 milli-Ohms which means 0.030 - 30
|ohms, and 3 - 3,000 GOhms ??? (that's awfully high)
|
|Under Resistance Range it says 10 - 30,000 KOhms which is 10 - 30
|MOhms, somewhat shy of the 3,000 GOhms mentioned earlier.
|
|For a start, it would not be possible for any field service test
|instrument to be capable of actually measuring in the GOhm range with
|any degree of reliability and repeatability. For starters, the
|moisture content of the air resting on the probe tips would give a
|reading without them even being in contact with any item being
|measured.
|
|I think the real maximum range is actually 30 MOhms so that is all you
|would need to verify under calibration.

 

[Palinurus]

Ross Herbert wrote:

I would be suspicious of the specs in this table.

Under Ranges it says 30 - 30,000 milli-Ohms which means 0.030 - 30
ohms, and 3 - 3,000 GOhms ??? (that's awfully high)
The milliohms is a typo. They mean megohms.


For a start, it would not be possible for any field service test
instrument to be capable of actually measuring in the GOhm range with
any degree of reliability and repeatability.
And yet, they do. We have test fixtures up to 10 GOhm, but they only go

up to 5kV. We also have a 10 GOhm voltage divider, looks something like
a Van de Graaff generator, that will handle anything up to 100 kV
(during which time we treat it with great respect,) but it's a little
massive to move around. I'm looking for something that can fit on a
benchtop. Measurements are repeatable.

For starters, the

moisture content of the air resting on the probe tips would give a
reading without them even being in contact with any item being
measured.
And yet, they don't. A megger on the gigohm ranges will simply

overrange if not connected to anything. I think I can see how you might
get that impression from the textbooks, though. I work on the damn
things, so I don't have to theorize.

I think the real maximum range is actually 30 MOhms so that is all you
would need to verify under calibration.

Ah, if only it were so.