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Thermal Imaging Camera Recommendations?

DiffAmp

Jan 5, 2016
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Hello, I'm looking for a thermal imaging camera for measuring electronic component temperatures. Finding a camera looks like a research project in itself, and I'm hoping that someone with experience in this area can offer some advice. I want to look at power devices that are no smaller than 5mm square, ~5% measurement accuracy, 0.5 second update rate.

A specific camera recommendation would be great. Manufacturers? What specifications are important? How much do I need to spend?

Thanks!
 

DiffAmp

Jan 5, 2016
7
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Jan 5, 2016
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Thanks, I've done Google searches and there are a lot of cameras to choose from over an enormous price range. I know about emissivity, and that will not be a problem.

I'll contact a few manufacturers and speak to some sales folks. If I do manage to learn anything useful, I'll post it.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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The problem with thermal imagers (Forward Looking Infra Red or FLIR cameras) is calibration. Without knowing the emissivity of what you are "measuring" the numbers are almost meaningless with regards to component surface temperature. And emissivity is a function of temperature too. However, if all you want are relative temperatures (this device is hotter or cooler than that device) then perhaps a small hand-held microbolometer such as this one will do the job.

I last worked with calibrated thermal imagers in the 1980s, among other things laying out ground-truth targets for overhead image collection systems. We also collected infrared "signatures" of various objects in the 3 to 5 μm and 8 to 12 μm infrared bands that have an atmospheric "window". Back in those days, you had to use cyrogenically cooled (liquid nitrogen) photo-conductive detectors. And if you wanted an image, you had to mechanically scan it across a single detector. A few years later cooled detector arrays became available (at exorbitant prices) for use as staring sensor planes. And shortly after that, microbolometer arrays appeared on the scene.

Microbolometers have a poor D* rating compared with cyrogenically cooled detectors, but they work well when there is a large temperature difference between objects and the background radiation. And they are a LOT less expensive than an infrared-sensitive detector array. FLIR and Fluke are the go-to companies for inexpensive, hand-held, infrared imagers employing microbolometer technology.

I'll contact a few manufacturers and speak to some sales folks.
That's the best way to approach your problem without having to invest a lot of time. I have found manufacturer's reps and sales people from authorized distributors are generally very knowledgeable about their product lines and can help a lot in choosing a suitable product. Some may even loan you a demo camera for a few days (or weeks) and later offer it for sale at a small discount (since it is "used"). It doesn't hurt to ask about that, although AFAIK the low-end (less than $500) imagers are not high-margin items for distributors. Of course, once you find something you like, there is always eBay...
 

DiffAmp

Jan 5, 2016
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Thanks, you make me wonder if this will work, and if I know as much about emissivity as I thought I did...

I usually use diodes as temp sensors, but sometimes it's difficult to make a decent thermal connection. For example, I can solder one diode lead to the tab of a transistor and get a pretty accurate measurement. But I'd like to know what the temp is in the middle of a 2W 2512 SMT resistor during a short duration overload. My plan is to solder a diode to one end of the resistor to give me a reference temperature at the end of the resistor, then use imaging to look at the difference between that temperature and the center.

Off-line until 2/22.
 

Tha fios agaibh

Aug 11, 2014
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It's a matter of how much your willing to spend, and what you need it for.
For what I use one for, I'm not too particular about accuracy. I just use mine for picking out hot spots. I've got an Flir E4 and modified the software to improve its resolution. So basically I've got the E8 resolution at the E4 price.
 

mww

Mar 7, 2016
4
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Mar 7, 2016
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Another option is a civil fire service imager from the likes of eBay, then refocus the lens to close in. That would be a 320x240 pixel image which is better for PCB than the 80x60 pixels in the likes of the Flir TG165. OK they add in a visible image to help, but close in the parallax will kill it.
 
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