Hi all, In the search for small heaters/ resistors, my boss removed the plastic from one of these Ohmite thick film resistors.
George H.
These are cool, thick film on porcelanized steel.
They handle enormous transient power peaks.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
$23 apiece, wow.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
They only cost us $19!
We're using them to replace a military-type (bolt-down gold aluminum block) 250 watt wirewound power resistor that was failing from pulsed loads.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Yes, those tubular aluminum bolt-down units are basically just vitreous ceramic wirewounds cemented into a heat sink case. They are good at getting the heat out without going to insane temperatures (assuming adequate heat sinking to whatever they are bolted to) but have only about the same peak power capability of an air-cooled wirewound resistor.
Jon
So now you know the Ohms/square. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
It's very likely laser trimmed.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Should be visible. And easily calculated if you can use one of your "crutches" ;-) ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
It's easy to calculate ohms/square, given a visible (maybe L-shaped, maybe multiple cut)laser trim on a rectangular ohmic patch?
Tell us how.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
You forget I used to run the Dickson Electronics hybrid facility (NW corner of Thomas & Pima... I think it's Siemens now-a-days) and trimmed thick film every day. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Do an easy case: 1 ohm per square, 1 square, contacts on two sides, 1 ohm untrimmed, single narrow cut sideways, starting in the middle of one non-contact side.
contact ============================ | | | | | | | cut | |------- | | | | | | | | | ============================ contact
Post the equation for ohms as a function of cut length.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Doesn't take any math (or equations) to get the _sheet_resistivity_ (which was the original statement, NOT Ohms per cut length), it just takes intuitive thought >:-}
As you emphasize, "Math and simulation are both crutches".
As soon as you admit you don't know how to attack the problem, I'll tell a trivial way to get an answer. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
You said the laser cut math was "easily calculated". You said you did trims every day. So do the math and post it.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
What's your middle name, "Subterfuge"?
I said, "So now you know the Ohms/square."
In...
Date: Wed, 19 Mar 2014 14:28:33 -0700 Message-ID:
Stuff it up your nose, you can't even begin to present a solution.
There's a trivial way... shown _immediately_ upon your statement of incapability >:-} ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
It's thick film, so I'm not sure (haven't done it for 41 years... don't know how well the technology has progressed in that much time) that 5% is doable with not only the paste variation, but the screen motion control. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Put up or shut up.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
So you can't even think of a way ?>:-}
Those of you who are curious, E-mail me... it's trivial, but wa-a-a-ay out of Larkin's capability >:-} ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Sad old fool. That's your standard ploy when you can't put up: go "private."
Somebody should call you on that.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
the plastic from one of these
5w/dp/64K6797
looks like just a big glob.
Not at 5% it is not.
?-)
You're the "sad old fool". "Sad old fool" isn't a physical age, it's a mental age, and Larkin, you're the "sad old fool" mentally.
There's a trivial way to derive the information we are seeking, but you're too dense, AND TOO HATEFUL, to find it.
Go away, mental midget, you're tiresome... everyone with half a brain... even those with a full brain, but half of it tied behind their back, will ignore Larkin. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.