MATRIX DC Power Supply Variable, 32V 6A Adjustable Bench Power Supply 4-Digit Display 5 Sets Storage, Switching Regulated DC Lab Power Supply with Encoder Knob, Smart Fan and OCP/OVP/OTP (MPS-3206)

OK I have to admit that I bought this power supply for exactly one reason: It's short. Every other hobby-class power supply I could find was tall (>6") and narrow. I had a space on my workbench that required one that was short and wide ("landscape" instead of "portrait"). I had recently bought the Matrix MPS-3010D+ linear power supply and been impressed with the quality, so I figured maybe this one would be good too. That said, I'm quite pleased with it. I currently have six bench power supplies (both linear and switching) in the house, and this is not the best, but it's also not the worst. And given the size and price it's a great deal.I originally thought I would hate that you can't just change the voltage or current without pressing a button, but actually I love that feature. It means I don't have to worry about bumping a knob and frying my circuit. Likewise, other reviewers have complained that when you press the V/I button, it doesn't remember which digit you were previously using, but I've come to think that's a good thing too for the same reason. It always starts with the least significant digit, so there's no danger of dialing in a high voltage or current by accident.- When you first power on the unit, the output is turned off, which is good for safety. The ON/OFF button toggles the output.- It remembers the last V/C setting you used.- There are 5 memories that are easy to use. Just long-press a button to store the V/C setting or short-press to retrieve it.- Long-press the OVP/OCP button to set over-voltage limit. Long-press again to set the over-current limit. While in these modes a short-press of the button turns on or off the OVP and/or OCP feature. These are absolute values that if the PS exceeds (actual output, not set output) it will go into a fault state regardless of whether you've actually manually selected a higher V/C in the main setting.- In normal operation, the display shows actual voltage and current (in constant-current mode, the voltage will be less than the set point).- When setting the voltage/current, the output changes in real time. The current display shows the SET current, not the actual current, while changing the voltage. So be careful changing the voltage if you're worried about too much current being drawn (this is actually a great time to use the OCP mode, which shuts off the output if this happens).Now, for accuracy. All measurements were made with a Siglent SDS 1104X-E scope with the PS feeding a 50 ohm dummy load (max 0.6A @ 30V) and with a cheap multimeter (DMM).Set 0.10V = ~100 mV RMS (103.5 mV DC on my DMM), Stdev 4.8 mV, ripple < 100 mV p-p, 2 mV RMS @ ~500 HzSet 1.00V = ~910 mV RMS (996 mV DC on my DMM), Stdev 48 mV, ripple < 100 mV p-p, 4 mV RMS @ ~1.8 kHzSet 5.00V = ~4.95V RMS (4.99 V DC on my DMM), Stdev 60 mV, ripple < 100 mV p-p, 5 mV RMS @ ~14 kHzSet 30.00V = ~30.15V RMS (29.9V DC on my DMM), Stdev 180 mV, ripple < 200 mV p-p, 5 mV RMS @ ~200 kHzSo in general voltage is quite accurate, especially when measured with a DC DMM, although it seems a little worse than spec when using RMS on the AC scope (note spec is usually done at full load, which I couldn't do). Ripple is within spec and isn't bad for a switching power supply, but as other people have said it might not be the best choice for RF work. Putting my spectrum analyzer next to it I don't see any obvious emissions from 10 kHz to 1 MHz and it hasn't interfered with my ham radio 2 feet away.Unlike a lot of other PS I've tested, this one never has a voltage overshoot when you turn off the output, or when you turn off the entire PS. When you turn off the output, it takes ~100 ms for the voltage to drop from 10V to zero and 75 ms to rise from zero to 10V when you turn it back on. These delays are normal for a switching power supply.All-in-all I'm quite pleased with this PS. It has a lot of features other units in its price class are missing, and it seems to be accurate and "clean" enough for most uses. I highly recommend it.

After quite a bit of research trying to find a good quality but reasonably priced power supply, I decided to give this one a try for some projects I have. I am happy to say I am very pleased with the quality and functionality of this power supply, and I really like the ability to cut power to the leads while making adjustments. The memory functions are very nice to have as well and it has a wide range of voltage and current settings to meet my needs. It’s an all around good product for someone like me, who is a tinkerer, but I imagine it would work very well for more serious enthusiasts as well. At least that’s what I gathered from my research. I would not hesitate at all to recommend this as a bench top power supply.

I have been using this for 3 months. It has one problem. It kills its own power switch. It seems to be a design problem. When the power switch is turned on or off, it generated spark across the contacts and melts the contact together. I have replaced the original switch with some cheap small switches. They were killed almost right-away.I'm still waiting for a replacement switch. Hopefully, they'll send a better quality switch that will not get stuck.Another small problem is the way it remembers the Volt and Current settings when you turn it off. Ideally, it should keep whatever setting it was at the time you turned it off. But it does not, it remembers only the last settings you recalled from the memory. So, say, you have a memory setting of 12V and 1A. You recalled it. After that, you changed the setting to 5V 0.1A, without saving to a memory. You turn it off and back on. The setting will be 12V and 1A. It has caused me a little problem once. I turned it off and on again without checking.For the price, this is a very good value. It's a switching power supply, so there is noise on the output. But it has the control for output on/off. It measures current down to 1ma. It also has memories to store frequently used settings.It is very small, much smaller than the normal bench top power supply.4/22/2022, I did receiver a couple of replacement power switch. I put one in and have not had the problem since.

The MPS-3206 power supply was tested and met its specifications. Additional testing showed reasonable performance for a bench power supply in this price class. While this power supply is rated at 6A, over current protection can be set as high as 7A. The voltage and current can be set precisely in 1mV and 1mA increments using the digital setting knob. A press of the knob selects the digit and rotating it moves the value up or down. Not as simple as an analog knob, but can easily get more accurate settings than an analog knob.Power Out: 15V at 6A (90 watt), ran for 1 hour with no issues25V at 6A (150 watt), ran for 1 hour; temperature at exhaust fan air outlet 85FMeter Accuracy: Both voltage and amps were within 1% of my 1% accuracy meterNoise at 90W and 150W: 100mV p-p, main frequency of noise ~50kHzNoise with no load: 10mV p-p, main frequency of noise ~20 MHzFan: Off at lower power, somewhat noisy when on, measured 52 dBA at 1 meterTested it charging a LiFePO4 battery at 2A. Many of the inexpensive power supplies have difficulty regulating current, particularly near the transition between constant current and constant voltage. This power supply showed a maximum p-p variation in charge current of 15mA measured at 1 second intervals. No current variation was seen when driving a resistive load in constant current mode.