UNI-T UTP3315TFL-II (2025) Linear PSU review

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Review of UNI-T UTP3315TFL-II (2025) 30V 5A linear PSU A laboratory power supply is one of the essential devices a DIY hobbyist should have, whether built or purchased. The internet is full of schematics from experienced electronics engineers showing high-quality power supplies with various features that differ from commercial products. In my case, I also used various "adapters" — power supplies from different devices such as mobile phones, laptops, and similar — sometimes combined with Chinese voltage and current control modules. While doing that, I was also gathering schematics and knowledge to better understand what to choose from the available options that would meet my expectations. In the meantime, the opportunity arose to buy a commercial product... but which one to choose? What I already knew (from watching videos by experienced electronics repair engineers) is that it should preferably be "linear". This means it operates on an analog principle, not a digital one. Linear power supplies are generally easier to repair if something burns out inside, simpler in design, more robust, and usually do not include various "safety" limitations that can interfere with the main purpose — delivering the set current even into a short circuit. The core of linear power supplies is a large iron transformer, which is quite heavy; for a 30V 5A unit it is around 4 kg. And it is well known that Chinese manufacturers would gladly make better use of those 4 kg of iron and copper... Switch-mode power supplies (SMPS) usually come with many buttons, and it takes more time and steps to set the desired values. Once configured, they can store presets. Of course, there are also SMPS units that can deliver the set current into a short circuit, but you should always verify that before purchase. I believe switch-mode supplies can be very practical for people who frequently design on breadboards and experiment with electronics. They are lightweight — around 1.5 kg including the case — and this is often advertised as a positive feature ("look, it's not heavy!"), even while the product is labeled as a LINEAR lab power supply... In terms of form factor, there are those "box-shaped" generic power supplies that used to all be linear and the cheapest option. Sorin bought one of those for 50 dollars a few years ago... but today, prices for linear supplies have increased significantly. What you should know is that in such "generic box" power supplies, you will mostly find switch-mode designs today, and physically there is no way to fit a 60V/5A or even 30V/10A linear supply inside. With such devices, you never really know what is inside, even if it says 30V/5A on the label, because the brand name often exists for only a year before changing. Chinese manufacturers are least concerned with specification accuracy, and you can often see simple copy-paste specifications everywhere. That is why I chose the UNI-T brand, which has been present for a long time, and whose internal design is more or less known — or at least more trustworthy, although even that can change with ongoing development. www.youtube.com/watch?v=yvCeTv3a0Ac UNI-T UTP3315TFL-II (2025) Linear Power Supply 30V 5A Review Sequa coupling caps The power supply arrived undamaged, and upon first power-up I heard exactly what I expected... the fan runs at full speed all the time. Do not be misled by the "low noise" label and the speaker icon on the packaging — this is how Chinese manufacturers translate "low ripple", which refers to low output voltage ripple, a typical characteristic of linear power supplies. I immediately started designing a small smart fan controller (a truly smart one), and today that project is finished with great satisfaction. It now works exactly as intended: the fan runs at minimum speed up to 30°C (virtually silent), and then increases its speed proportionally (linearly) as the heatsink temperature rises, reaching full speed at 50°C. The result is cooling that is truly proportional to the actual need at any given moment, without unnecessary noise. As soon as the load decreases or stops, the fan quickly adapts to the new conditions... a pleasure to use. Aside from that, the power supply performs well and I am satisfied with it. Both voltage and current can be easily adjusted using coarse and fine potentiometers, which move smoothly. The display is clearly visible from different angles and is not overly bright. The only drawback is the very small heatsink, which definitely needs to be replaced if you plan to use the unit at higher voltages and currents. Fortunately, there is enough space inside the enclosure for a proper heatsink — which will be the next project

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Sorry, I forgot that badcaps has problem with formatting...

[stj]

i was about to say, thats a wall of text!

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Yes, the problem is, that I see text formatted in quick edit box... but as soon I posted, it eat all formatting and add some garbage after hash sign... I cant edit later. But, who cares that "forum" works only in new browser, the forum, aka news group, bare text, point on sharing information, knowledge... I posted the same article on Sorin forum, and on eevblog forum: https://www.eevblog.com/forum/testge...ar-psu-review/ ... but from some reason I can not visit sorins forum anymore... so sad that tehnology is fall apart...

[stj]

gotta love how a ban is listed as an error!

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That message is poped up after migration from .com to .co.uk domain I think, sorin announced to know about forum problem, so I wait... message about ban is showing at the time now, but ban is set automaticaly for unknown reason. I was not noty