If you’re working with U bracket switching power supplies, you probably know how finicky temperature can be—one bad reading or misstep in testing and your entire project could go sideways. When I first started out as a supplier of these units, I thought measuring their temperature coefficient would just be a quick check during production. Turns out? It’s way more hands-on than that, and skipping steps here will leave you with products that fail when a customer actually needs them. Let me walk you through how we do it at our shop, no stuffy jargon, just what works for U bracket units specifically. U Bracket Switching Power Supply
First, let’s keep it simple: the temperature coefficient (TC) here is just how much your power supply’s output voltage drifts when the temperature changes. For our U bracket models, that drift can mess up sensitive gear—like medical devices or industrial sensors—so we take this test super seriously. And yeah, I get it, not everyone has a lab full of fancy gear, but you don’t need that much to get accurate numbers. Let’s break it down step by step, the way we do it for every unit we ship.
First, prep your test setup right. I’ve seen too folks cut corners here: they plop a power supply on a workbench near a window where the temp jumps, or use a cheap thermometer that’s off by 5°C. For U brackets, we use a temperature-controlled chamber—nothing brand new, just a reliable one that can hold steady temps from -40°C to 85°C (that’s the standard range for most industrial and consumer U brackets). Next, you need a precision digital multimeter—no $20 ones here, get one that measures voltage to at least 0.001V resolution, because even a tiny drift matters. Also, a calibrated thermocouple taped right to the U bracket’s surface, not just inside the chamber—air temp isn’t the same as the power supply’s actual temp, especially with U brackets that dissipate heat through their metal frame. Oh, and make sure the power supply is loaded correctly; most U brackets are rated for a specific load, so we use a resistive load bank that matches that—like if your unit is 12V 5A, set the load to 5A steady. No half-loading here, that’s how you get wrong TC readings.
Wait, one quick thing before we start: always let the power supply warm up first. I know you want to rush, but if you test it right after turning it on, the voltage will shift a lot just from the unit heating up itself. For U brackets, we run them at full load for 30 minutes before testing—once that’s done, we let it stabilize in the temperature chamber too. That’s non-negotiable.
Now, the testing process. First, set the chamber to 25°C—room temp, basically, that’s our baseline. Let it sit for at least an hour so the thermocouple on the U bracket reads exactly 25°C, no fluctuations. Once that’s stable, take a reading of the output voltage with your multimeter, write that down as V_base. Got that? Now, we test both extremes, because TC isn’t just one number—it’s the drift from room temp to low temp, and room temp to high temp. That’s how our U brackets perform in real life, right? If a customer uses theirs in a freezer unit or a desert, we need to know both ends.
Next, cool the chamber down. Set it to -40°C, and I mean truly stable—wait until the thermocouple on the U bracket is holding at -40°C for 20 minutes straight, no small shifts. Then take your output voltage reading here, call that V_cold. Do the math: TC for cold is (V_cold – V_base) divided by (V_base * (T_cold – T_base))—T_cold is -40, T_base is 25, so that’s a temp delta of -65°C. For our U brackets, we want that number to be under ±0.05% per °C, because anything higher means the power supply will drift too much for sensitive apps.
Then heat things up. Set the chamber to 85°C, same rule: wait until the U bracket’s temp is steady at 85°C for 20 minutes, no blips. Take that voltage reading, call it V_hot. The hot TC is (V_hot – V_base) divided by (V_base * (T_hot – T_base))—temp delta here is +60°C. Again, for our U brackets, we cap that at ±0.05% per °C. And here’s a trick we figured out over the years: don’t test the chamber air temp, test the U bracket’s surface temp. Metal brackets hold heat differently than air, so if your thermocouple is on the unit, not the wall of the chamber, your numbers will be spot on. We had a customer once who thought their U bracket was bad because they were using chamber temp, not the unit’s, and turns out our TC was totally fine—just their test setup was wrong. That’s a mistake we avoid at all costs.
Wait, what if you don’t have a temperature chamber? I get it, not every small shop has one. For quick, rough checks, you can use a freezer and a toaster oven—just make sure to let the unit stabilize for a long time, and account for temp lag. But for actual production testing, we’d never skip the chamber, because that’s how we ensure every U bracket leaves our facility meeting spec.
Now, some common pitfalls people run into with U brackets specifically, not just any power supply. First, the U bracket itself—since it’s a metal heat sink, it can create hot spots on the power supply’s circuit board. If your thermocouple is not placed right, you’ll get a wrong temp reading, which messes up your TC calculation. We tape our thermocouple to the side of the U bracket closest to the power supply’s main IC, because that’s where most of the heat comes from. Second, loading the power supply wrong—if you run it at less than rated load, the output drift will be smaller, which is misleading. Always test at full rated load, that’s what the customer will use it at, right? Third, not letting it stabilize. I’ve seen a guy rush through a test, take a voltage reading 5 minutes after changing the temp, and end up with a TC that was half the actual number. Don’t do that.
Another thing: some U bracket switching power supplies have different TC specs for different models. Our 15V low-profile U bracket has a TC of ±0.03% per °C, while our 24V high-power one is ±0.05%—we tailor it to what the customer needs. If you’re designing a product that needs ultra-stable voltage, you can specify a tighter TC, and we can adjust our manufacturing process to meet that. We don’t just ship one TC for all units, we customize based on your application.
Now, why does this matter for you, the customer? If you’re using a U bracket power supply in a device that can’t handle voltage drift—like a precision test instrument, or a medical pump that delivers consistent doses—your whole product will fail if the TC is too high. A lot of cheap power supply suppliers skip proper TC testing to save time and money, and that’s why you might have had a bad experience before. At our shop, we test every single U bracket before it leaves, not just sample units, because we know how important this is. We even keep a log of each unit’s TC reading, so if a customer ever has a question, we can look it up right away.
Wait, let’s talk about how to confirm a TC reading once you get a unit. If you receive a U bracket from us and want to verify, you can do your own mini test. Set up your multimeter, tape a thermocouple to the U bracket, put it in a controlled space (like a closet where temp doesn’t shift much for 24 hours) to get your baseline. Then put it in the fridge (not freezing, just cold) for 2 hours, check the voltage, then put it near a heater (not too close, avoid overheating) for 2 hours, check again. The delta between the two voltages divided by the temp difference is your approximate TC, and it should match what we specify. If it’s way off, just reach out to us—we’ll sort it out, no hassle.
Now, let’s wrap this up. Measuring the temperature coefficient of a U bracket switching power supply isn’t rocket science, but it does require patience and attention to the small details specific to these metal-framed units. Skip the warm-up period, test on the unit’s temp not the chamber’s, load it correctly, and test both hot and cold extremes, and you’ll get accurate, useful numbers.
If you’re in the market for U bracket switching power supplies that come with verified low TC, or if you have questions about testing your own units, we’re here to help. We work with all kinds of customers—from small electronics startups to large industrial manufacturers—and we can tailor our products to meet your specific needs. Whether you need a standard model or a custom one, just reach out to us to discuss your requirements.
Enclosed Switching Power Supply References
- Texas Instruments. (2021). Temperature Coefficient Measurement for Switching Power Supplies. Application Note SLVA892.
- International Electrotechnical Commission. (2018). IEC 61204-3: Adjustable DC power supplies – Part 3: Safety requirements for switching power supplies.
- Analog Devices. (2020). Precision Voltage Measurement Techniques for Power Supply Characterization. Technical Tutorial MT-001.
Guangzhou Kaihui Electronics Co., Ltd.
Guangzhou Kaihui Electronics Co., Ltd. is one of the most professional u bracket switching power supply manufacturers and suppliers in China, specialized in providing the best customized service. We warmly welcome you to buy high quality u bracket switching power supply made in China here from our factory.
Address: 2F BLDG8, Standard Ind.Park, Dongchong Town, Nansha District 511453, Guangzhou, Guangdong, China
E-mail: amy@gzkaihui.com
WebSite: https://www.kaihuipowersupply.com/
