Author Topic: non cut resistors  (Read 402 times)

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Online coppercone2Topic starter

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non cut resistors
« on: December 13, 2024, 04:36:24 pm »
Most resistors are some kind of winding. Metal oxide, films, wirewound.. all have a helix structure


Which resistors are uniform. Composition resistors (ceramic, carbon) are one.

Are there others?
i.e. making a resistor controlled by deposition thickness only
 

Offline TimFox

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Re: non cut resistors
« Reply #1 on: December 13, 2024, 08:14:20 pm »
Some carbon film TH resistors are not helixed (low resistance, high resistivity).
For high-power RF applications, carborundum ("Globar") SiC resistors can be non-helixed.
The Vishay RNC90 metal-foil resistors have a planar pattern that is "non-inductive" due to a serpentine pattern.

[edit:  changed RC90]
« Last Edit: December 13, 2024, 09:59:15 pm by TimFox »
 

Online tooki

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Re: non cut resistors
« Reply #2 on: December 13, 2024, 08:45:17 pm »
Most resistors are some kind of winding. Metal oxide, films, wirewound.. all have a helix structure


Which resistors are uniform. Composition resistors (ceramic, carbon) are one.

Are there others?
i.e. making a resistor controlled by deposition thickness only
Look for "pulse" or "surge" resistant/tolerant thick-film resistors. Those want to avoid narrow bottlenecks that could become hotspots, so as I understand it, they do indeed work on the volume resistivity of the resistive thick film. I don't know whether they laser-trim those or not, and if they do, whether it's done the same way as on thin-film resistors.
 

Online tooki

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Re: non cut resistors
« Reply #3 on: December 13, 2024, 08:49:27 pm »
The Vishay RC90 metal-foil resistors have a planar pattern that is "non-inductive" due to a serpentine pattern.
You sure about that model number? Google finds nothing at all for "vishay" "RC90" resistor.
 

Offline daqq

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Re: non cut resistors
« Reply #4 on: December 13, 2024, 08:59:08 pm »
Specialty RF resistors are AFAIK structured in such a way that they are a resistive line. These fellas are a tad extreme, but they do get the point across: https://www.vishay.com/en/product/53086/

Then there are special pulse rated resistors such as these monstrosities: https://www.hvproducts.de/wp-content/uploads/2021/04/washer_resistor.pdf . Ceramic composite are another material that's used in that way and also use their whole mass as a resistor.

And of course higher current shunts - pretty much a slab of metal.
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Offline edavid

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Re: non cut resistors
« Reply #5 on: December 13, 2024, 09:38:47 pm »
The Vishay RC90 metal-foil resistors have a planar pattern that is "non-inductive" due to a serpentine pattern.
You sure about that model number? Google finds nothing at all for "vishay" "RC90" resistor.

I believe he meant RNC90.

Datasheet:
https://www.digikey.com/htmldatasheets/production/1313242/0/0/1/rnc90x-z-foil-mil.html
 
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Offline TimFox

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Re: non cut resistors
« Reply #6 on: December 13, 2024, 09:58:43 pm »
Oops--I corrected my post.
 
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Online coppercone2Topic starter

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Re: non cut resistors
« Reply #7 on: December 13, 2024, 10:07:00 pm »
that looks like a creative way to make a flat spiral
 


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