WANTED: Vishay Dale 100K 25W High Voltage Resistor ( Non inductive )

[Mark]

Hi All,

I need one or two Vishay Dale 100K 25W High Voltage Resistors ( Non
inductive ).

I have contacted Vishay , who appear to only beable to supply in large
quanities made to order.

The resistors part number is: HL-25-06Z

Any help at all would be grately appreciated.

Many thanks in advance,

Mark

 

[John Robertson]

Tried asking for "samples"? otherwise digi-key.com or others probably
sell this.

John :-#)#

Hi All,

I need one or two Vishay Dale 100K 25W High Voltage Resistors ( Non
inductive ).

I have contacted Vishay , who appear to only beable to supply in large
quanities made to order.

The resistors part number is: HL-25-06Z

Any help at all would be grately appreciated.

Many thanks in advance,

Mark

(Please post followups or tech enquires to the newsgroup)
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[legg]

Hi All,

I need one or two Vishay Dale 100K 25W High Voltage Resistors ( Non
inductive ).

I have contacted Vishay , who appear to only beable to supply in large
quanities made to order.

The resistors part number is: HL-25-06Z

Any help at all would be grately appreciated.

At 100K, stray inductance is unlikely to be an important physical
property - capacitance is more likely to affect bandwidth accuracy.
This is why non-inductively wound parts are so much more common below
1K, and why they want a special order to make them. Note that the data
sheet does not even list non-inductive values above 8K8 in the NHL 25W
body size.

I note that these parts are also not listed as being available in
tolerances closer than 5%.

Rather than employing HV parts, why not just use two or more standard
voltage precision parts in series? These will be much more easily
obtained and more versatile in application - they need not even be
wire-wound. Stray capacity can be controlled by paralleling known
capacitance values in the divider chain.

RL

 

[Mark]

At 100K, stray inductance is unlikely to be an important physical
property - capacitance is more likely to affect bandwidth accuracy.
This is why non-inductively wound parts are so much more common below
1K, and why they want a special order to make them. Note that the data
sheet does not even list non-inductive values above 8K8 in the NHL 25W
body size.

I note that these parts are also not listed as being available in
tolerances closer than 5%.

Rather than employing HV parts, why not just use two or more standard
voltage precision parts in series? These will be much more easily
obtained and more versatile in application - they need not even be
wire-wound. Stray capacity can be controlled by paralleling known
capacitance values in the divider chain.

Interesting idea,

I already know the specification of the part I have.

As for bandwidth!!! Where do you think this part is being used?

Non inductive values are available to 10M according to Vishay.

 

[Mark]

Tried asking for "samples"? otherwise digi-key.com or others probably
sell this.

John :-#)#

Thanks John,

I'll hassle Vishay for a sample!

 

[William P.N. Smith]

As for bandwidth!!! Where do you think this part is being used?

Dunno, you didn't say. Given that that's 1500 volts, or probably 1KV
with decent derating, probably something like a radio...

 

[legg]

Interesting idea,

I already know the specification of the part I have.

As for bandwidth!!! Where do you think this part is being used?

Does it matter? You're obviously not worried about the effective
loading presented to the source.

Pulsed applications will have the same reactive considerations as
simpler wide bandwidth circuits, within the 1% tolerance you refer to,
and will typically be capacitively trimmed at at least one location,
if a divider is required for measurement/gain accuracy.

Note that non-inductive winding methods can actually aggravate
self-capacitance to the detriment of bandwidth accuracy.

At RF, you would not be using an inconvenient or wasteful load R, nor
would you be using wirewound parts, unless completely bypassed.

......and if it's still all just on paper, then you're pulling my
chain.

RL

 

[Mark]

The resistor is in a 35KV PSU as part of a ballast resistor chain of 8
resistors to supply a CO2 Laser tube.

This may help...

 

[legg]

The resistor is in a 35KV PSU as part of a ballast resistor chain of 8
resistors to supply a CO2 Laser tube.

This may help...

Then definitely don't forget the capacitors.

RL

 

[Mark]

Then definitely don't forget the capacitors.

Hmmm... and why would I need capacitors added to a circuit that was design
not to use capacitors?

 

[legg]

Hmmm... and why would I need capacitors added to a circuit that was design
not to use capacitors?

I'm afraid that you are in a much better position to ass-ess this
requirement, than I am. Please consider my chain successfully pulled.

Note that for 2uSec pulses, 32uH and 160 pf are your 1%, 10fc stray
limit values in a 100K resistor location. This may help if you are
still on paper and are considering what type of component to use in
the ballast positions.

RL

RL