Thermal cameras have traditionally been very expensive, often costing thousands of dollars. Today there are a variety of options that are far more affordable, making them ideal for hobbyists and as a low-cost engineering tool. For electrical engineers thermal cameras have a variety of uses.
Thermal cameras can be a valuable tool for PCB debugging. With the help of a thermal camera, an engineer can easily see if an IC is heating up drastically, a voltage regulator is climbing close to its temperature limit or if any other parts are too close to their power rating. For example, here is a the inside of an iPhone 4s. Notice how the areas around the processor are hotter. Most people could assume that fact, but how much hotter is it than the other components? This temperature differential would be difficult to see with other means.
Here is another example, a typical 1k 0.125w resistor with 9v across it.
Thermal cameras can be a valuable tool for working with and troubleshooting power electronics. For example here is a small gearmotor that has been ran at double its rated voltage. The DC motor has heated up as well as the bushing that the output shaft passes through on the gearbox.
Electrical wiring can be another practical use for thermal cameras. If a circuit breaker, outlet, or wiring is heating up these all can be signs that something may be wrong with the system. Here is an example of a power cable for a smartphone heating up during charging. The second image is of charger that the phone plugged into. Temperatures like this are pretty typical of chargers.
Today there are a handful of low-cost options available for thermal cameras. All of the images in this article were captured with a Seek Reveal camera. This is a rugged handheld camera with a built-in flashlight. It’s small, stand-alone, design makes it easy to toss in a pocket or bag. Besides Seek, other companies make thermal cameras such as FLIR and Fluke.
Seek Thermal Reveal
The Seek Reveal is a compact thermal imager that also contains a flashlight. The Reveal uses a 205px by 156px sensor that can measure temperatures from -40F to 626F. The Reveals flashlight is 300 Lumens and the brightness is controllable via the settings menu. The Seek Reveal contains a 320px by 240px 2.4" display and a microSD card to store the images to. The camera is powered by an internal 3.7v lithium battery that delivers up to 10 hours of run time. A major drawback with the Seek Reveal is the lack of adjustable emissivity, this could cause some measurements to have errors in them.
The TG Series is FLIR's entry level thermal imagers. The TG Series features an 80px by 60px FLIR Lepton thermal sensor that can provide measurements from -13 to 716F. The TG series comes in two different versions, the TG167 features a 50-degree field of view making it ideal for measuring temperatures from a further distance. The TG165 features a 25-degree field of view making it ideal for measuring objects that are closer, such as circuit boards! The duo of FLIR cameras feature the same 2" LCD display and an internal 3.7v lithium battery that delivers more than 5 hours of measurements. Unlike the Seek, the FLIR has adjustable emissivity.
Fluke VT04 Visual IR Thermometer
Fluke's low-cost option for thermal imagers is it's VT04 Visual thermometer. Fluke doesn't list the resolution of its thermal sensor, but this camera uses two separate image sensors that it combines. The VT04 uses a visual sensor like you would find a typical digital camera and a thermal camera sensor. This produces a hybrid or overlaid image of the two cameras resulting in an image that shows more detail. The dual cameras have a field of view of 28 degrees. FLIR also produces thermal cameras that produce hybrid images like this. The Fluke VT04 is powered by either 4 AA-sized batteries or a rechargeable Lithium battery depending on the version. Like the FLIR, the Fluke VT04 has adjustable emissivity.
With thermal cameras becoming cheaper every year, now might be a great time to get one for your toolbox. The cameras mentioned above are some of the entry level All-In-One cameras. Seek Thermal and FLIR make phone attachments, FLIR One and Seek Compact, that also provide similar functionality. The capabilities of these cameras far exceeded normal IR thermometers, plus an engineer can easily save the image and data. In the next few months, CAT is releasing a cell phone with these capabilities built in.