Bench Power Supply Full Review (variable 0-30V & 0-10A) QW-MS3010D 

Just bought one of these and this was a great explanation of how to use this power supply. Thank you.

Just what I needed! Thank you!

Very detailed great job explaining how the amps work!

Thanks for sharing! Nice explanation of how to use the constant current feature.

thank you very much! I will be receiving my power supply (exactly like yours) and I had my doubts about couple things but thanks to this video I was able to understand how to use it and feel more confident now when I receive mine. cheers!

Great explanation and video, wish I'd found it a few years back.👍👍👍

I have this exact PS and needed to get your input to keep from hurting myself. Thanks. Subbed.

Thanks for the video. It helped me out with the problem I was having with mine.

really nice demo. thank you so much. I have already destroyed many component.

Wonderful video, clear and concise. Keep it up

This is a fantastic power supply thanks for the link i will consider

Thank you. For your knowledge and the understanding I received, Randy Bentley

Thanks for sharing this excellent video and information. Yesterday I ordered a similar power supply manufactured by Longwei. Your video has been helpful and explains many features of the one I will be getting in a couple of days .😊

Amazing explanation. I was searching for it from long time.

Thank you for this!

Great Video, It helped me alot, Thanks

just got 2 of these one broken cheers for the heads up :)

Great video, and a nicely done description on how to operate those lower end power supplies. I've always wondered how the current limiting was done without all of the bells and whistles with those.

Although I've been a developer for at least educated for over 25 years, I'm only around 2 years into electronics as a self-taught 'hobby' so certainly a newb. I've only been playing around with my first PSU which is a very similar model for half a day now and I had to thank you for the MOST practical and useful info I've found yet. :)

Great vid well explained .

Very helpful video thank you 😀

thank you for the video i thought my power supply was broken straight out of the box lol well once again thank you for taking time to make this video you've definitely saved me from looking like a total idiot lol

Hi, great review. Does it drop to 16-18 volts when you drawing high current like 9-10 amps?

Great vedio Sir it's very clear.... 👍

Nice video sir.. Thank you for knowledgeable video

thanks sir ! so usefull.

I would have liked to see output on scope. Also, how well it controlled low currents,ie 10 mA. How well things works at each extreme is usually the real test. It's quite a good introductory review but not a full test and review. Quite helpful though for many. Perhaps you can do a follow up review in more detail.

Good video, good info.

the 900mA is NOT current protection but rather the Ohm's law.

Nice sir, its knowledge video.... Thanks sir.

The great video to learn

Excellent but do you calibrated you new lead resistance to your power supply

Thanks very informative

It would be super helpful if you would connect it up to an oscilloscope and show how much ripple the supply has in C.C. mode vs C.V. mode.

I have a dc power supply that I brought on eBay right,now is mess up the mosfet has shortened out but im going to fix it replaced the new mosfet when i first got mines it was kinda cool.

This is the video I was looking for, god dammit!.

Good Video. Can you do a short circuit test on these psu's? Eg. 200mA at 1.5V with output leads shorted.

Good information thanks sir

Excellent thanks

THANKS

The crooked label that is lifting of the panel is pretty funny.

Very nice Video!!

I touched the + to - when it started. It sparked and popped. Now when I start the device without the clips the voltage climbs to 5 volts. Isit broken? Any help is appreciated.

Thanks very good information , after your i have learn new stuff

Thanks for the video. I saw a model similar to this (just different branding) on Newegg for $60 so I might grab one. I don't need the resolution just yet, usually just need a voltage to debug phone circuit board and such.

No matter how much you turn up the current the load is just gonna pull what it needs to operate. It's called ohms law

Please explain the voltage connections minus, ground and plus. Do these allow a positive and negative voltage with reference to ground? I know you must disconnect the jumper from minus to ground. But I don't see a minus voltage or a positive voltage with ground as common reference.

Thank you for the video. Did you calibrate the meters at all? I also noticed the trim pots under the meters. Are they for calibration? Thanks.

thanks that is quite helpful

Thanks I was looking for a control for my 24 volt DC Power supply so I could use it for a variable, I found this particular type claiming 30 volts at 10 amps for ten bucks American free shipping from the US OF A! I can't find a power boost/buck that I Can get any cheaper, so I went ahead and put in my order. For what I need it for, if this performs anywhere near the claimed output I will be a happy camper, if not perhaps I can use the case and variable resistors to build a better PS from the leftovers.

dial 2 fast do you still have this because ive just bought one myself & was wondering if it's any good for zinc plating & it hasn't arrived yet so dont no myself until its here

Hey, I need a negative voltage to power some dual rail op amps. What is the cheapest power supply I can buy to achieve this? I am at home and do not have access to the campus labs

well good

would you recommend a powersupply like this for charging lipo batteries?

My friend, did it come with a schematic diagram, or just an instruction manual? Those settings that have two adjustment buttons on top, what do they do?

so because It has a short-circuit protection circuit, can I short-circuit this to, let's say, over-current wire to make it go incandescent?

Hi, I watched this video to find out what the yellow connector was for. I still don't know, but the rest was good, thanks.

amigo tengo una duda con mi power suplly es de 24v ajustable pero al mover el regulador de voltage al maximo llega a 28v sera malo usarla asi gracias

I have a question... I just bought the same model (QW-MS3010D). With or without the meter attached, my CV (Constant Voltage) indicator light flickers at or between 3 and 6 VDC. In addition I hear a clicking sound while the CV light flickers. My question is - is this supposed to happen? I don't think I need to be an electronics guru to know something isn't right - do you agree? When I watched your video, you CV light doesn't flicker, it stays solid. What are your thoughts on this? Any help is appreciated. Thanks in advance. :-)

WHY DID YOU NOT CONNECT AN AMMETER IN SERIES WITH THE CIRCUIT?

I have this supply. I cannot turn up the voltage unless I first adjust the coarse current knob until the c.v. light comes on.....also I can't set the current at all by connecting the two alligators. What's the problem?

Hey thanks for the helpful video. I do electronics repair and I have gotten tired of using 10 or 15 different power supplies and their different plug types to test radios and assorted gadgets. I couldn't find the 10 amp version so I settled for the 5 amp for $52, which I think is a good deal if I get a few years of service out of the unit. Is your power supply working well still?

I'm thinking about buying this for my workshop where I have a lot of different eBay electronics and lights, mostly 12V and 24V. What I thought was a bit poor with this is that it doesn't show less than 0.1A, but if I need an accurate reading of the current I can always hook up a multimeter in series with it. It costs about $75 on eBay right now, the same model number as this.

On my very same unit the knobs don’t adjust anything. I have 0v or max 30v can’t adjust voltage or current at all from very beginning. Where to look for a problem ?

They look exactly the same because they are the same! It is not made by Qal Way Electronics. They have just put their badge (sticker) on it. Which is why is comes in plain box and the User Manual isn't branded either. Shop around folks. Things that look the same usually are and some brands are a lot cheaper than others. :)

So ive got this 15v model how to icrease it to 24v since it has a 24 v output transformer

Hi sir how much minimum voltage you can get from power supply

It help a lot, thanks. You never said what the yellow button was for that sits between the back and red power button.

Does anyone know how far these power supplies can be floated above and below ground? I only want to use 2 of these in series in generate +/-15. Assuming this should be fine.

what is the "ground" for on the dc output?

So if you have a device that requires 12v, and say 3 amp, the power supply will sense this and up the amps to 3amp at 12volts? And there s no way to bypass the current protection feature if you want a specific voltage, and amperage.

A review of a 10A PSU with just 1A ???

Can you charge laptop batteries using your dc power supply.

on this or other ps.... how to do following... set to 12v dc FIXED... connect to music amplifiier...which is playing music.... and altho...the amp takes a Max of 1000 m A, i want to SLOWLY VARY ONLY THE CURRENT Limit from 100 to 1000 mA while hearing how the sound changes....

I just bought one identical to this one but its from Hong Kong and I only paid $15 for it. I'm hoping it does ok for the price lol.

Would something like this work fine using a breadboard to create LED lighting and other train related circuits for our HO Scale model railroad layout that has 15V across the tracks? Thanks!

What if I need to go more amps on this device, how can I do this?

I have a custom made battery pack made out of 324 Panasonic AA Eneloop batteries (Eneloop AA factory spec = 1.2 V/1900 mAh; actual tested spec = 1.43V/1.85 Ah which I will use for this example). Said battery pack has 9 AA batteries wired in series per column (9 x 1.43V = 12.87V/1.85 Ah) x 36 columns wired in parallel (36 x 1.85 Ah = 12.87V/66.6Ah). A freaking awesome 12.87 V/66.6 Ah battery pack that just keeps on going and going and going. However, when it comes time to charge the batteries, I spend about an 45 min taking the batteries out and putting them into the 4 bank charges that came with the batteries, then another 45 min taking them out of the chargers to put them back into the battery pack....yes, a royal pain in the butt. I have considered a 10 amp battery charger, but I have determined because I need to charge precisely to 12.8 V that I would be better off using a 12 VDC 10 amp variable power supply instead so that I can fine-tune it accordingly. I typically charge the batteries at 50% depletion so it should take me 3 hours or so to charge the battery pack at 10 amp. Question: Can I do this with this power supply? I assume there is no danger of overcharging because once it charges the battery pack to 12.8 V it just quits? Thanks for any help you can provide in this regard.

Think about Ohm's law! You missed something!

Sir can we use this for laptop repair ?

hmm guess I need more tutelage I just blue up my led light bar I set the voltage below the 12 v of the light and turned up the power

I have a old power supply But if i adjust the voltage to 13V and connect a 12V led it drop to 12V i can't rise the voltage up to 12V 😞 But i can decrease the voltage 12-0V (Power supply is 22V)

I see a small two potentiometer between the led display and the volt and current potentiometers .. what is that small potentiometer for ?

What is the purpose of the strip of metal between the ''Negative'' and ''Ground'' and will it cause any problems if I remove it?

Mine has an issue where it has trouble regulating below 300mA. Does yours?

I have that worked great for a year until it suddenly popped under light load the other day. I took the cover off and saw no viable damage and the display still works but the unit no longer gives power. Any idea what part when bad?

hi, i have this identical power supply but the other day it decided to not switch on anymore! checked the 2 glass fuses at the back and they not blown, any tips as what might be preventing to switch on?? thx

Hi i want to ask you if everything is solved by eletronic or inside is transformator

Does it still work? Have you ever connected it to a scope to check what kind of ripple it puts out? I'm considering buying one of ebay.

I bought one a month ago from an ebay seller and the display was blinking and then all of a sudden it went poof and smoke came out. The seller sent a replacement which I just tested. When I set it on current limiting and turn down the current it will make a faint, very fast clicking sound. is this normal or should I be worried?

I have one question you think this would work if i put an car amplified in home to use it at the house u think it gonna work

Helped a watt!🤣

I have a LW-3010KDS Power Supply 30V 10A but I don't understand why the max voltage is 26. I turn my voltage knob to the max but doesn't reach the 30V. Do you know why?

I really do not know whether I should make my own power supply or buy like that. Obviously fan sound disturbs me..

Mine is a 15v 3amp 1503DD model it works fine for powering stuff like bulb's moters anything that runs on electricity but it wont work for like zinc plating & that's the only reason i bought it for but i dont get nothing happening when i try to plate stuff of my bike do you have any ideas why this could be or does anyone in the comments no why this could be please? ? ?

good morning sir, sir i have one maxx dc power supply for mobile repairing when i connect the phone to the power supply and switch on the mobile device i found that current meter is fluctuating from 30 to 50 constantaly in every device so please tell me what is the problame

dude, did you test the max. 10 A specification ? you did only 0.9 A ?

hey, is it possible to keep a constant 12v while increasing/decreasing the amperage? for example I have an electrolysis tank which needs different amperage, however it is recommended to keep a constant voltage. So can I have 12v 2 amps then switch to 12v 1 amp? ect.

This is just incorrect to say that the power supply is protecting the load at 900 MA! The bulb he's using is a 12 V bulb that normally draws 900 MA. This is determined by the resistance of the filament in the light bulb. The bulb can't draw more then 900 MA at 12 V because it resists the current, and the resistance produces heat which makes it glow. If you lower the power supply's output current, the bulb will dim since it can't draw enough current to fully glow, and the voltage will also drop as well since less amperage being drawn also means less voltage is being drawn as a result of less electrons being able to get through the resistance of the filament. Basically you are "starving" the bulb of power by limiting how much it can draw... In effect this is now working as a bulb dimmer. You could dim a bulb by cutting the current, or cutting the voltage. Sure it will lengthen the life of the bulbs since you are not burning the filament at such a high temperature. This can also work in slowing down a motor, like a fan motor. If you starve it of current or voltage, the motor won't spin as fast since less electrons can flow through it... As for PROTECTION of electronics. Well if you were going to drive some LED lights, yes, limiting current will help prevent burning out the LEDs, since LEDs can draw more power than they can handle at a certain voltage and burn out. So for example, if an LED is rated at 3.3V and you apply the 3.3V directly with no current limit, it could overdrive the LED, as the LED would draw too much current and overheat. This is why resistors are generally placed in series with LEDs to prevent them from overheating. However if the power source is limited in amperage and voltage the LED won't be at risk. For example a 5V LED connected to a 3V lithium button battery will be fine since the voltage and maximum current are limited and won't overheat the LED. Otherwise when driving LEDs, it's important to limit the voltage and maximum current and this is when current limiting comes in handy. You could also limit the voltage and limit the LED to a safe brightness level where it doesn't overheat, but that is more risky... Regarding other electronic applications, electronics don't draw more power than they need. For example a radio will draw as much current as it needs to operate. Say a transistor radio will draw 50 MA of current at 1.5V. So if you hook it up to a 1.5V power supply capable of supplying 20A, that would be fine because the transistor radio will never draw more than it needs to operate, around 50MA. Of course if something shorted out, 20A might totally fry it. This is why generally electronic devices have a fuse or a current limiting resistor to limit damage in case of some short causing a huge inrush of destructive current. This is already built into the circuit. So if you hooked up a plug-in radio to a power supply and limited the current to something below what it requires, the radio won't operate properly since you would be starving it of power. If you lower the voltage below what it requires, it also will deteriorate in functionality. So a 120V clock radio might still work at 80V but below that, it will just stop working. If it needs to draw 5W and you limit it to 3W, it probably stop working. So the main reason for a variable Amperage and Voltage power supply is for electronics projects, repair and testing where you actually need to limit amperage or voltage in your application. One common scenario is charging some batteries. Batteries always need to be charged with some kind of current limiting, or they will overheat and explode. Say, a NiMH battery might recommend charging at 85 MA for 16 hours for a full charge. This will be a slow charge, it will limit heating the battery and extend its life. However you could speed up the charging by allowing 700 MA to run through the battery for only a couple hours. The battery will fully charge but will get quite warm which will reduce its longevity in the long run. This is when a power supply like this can come in handy, you can choose exactly how fast you would like to charge the battery. Normally battery charging is done by specialized circuits which use a smart chip to monitor the charge level and can stop the charging based on the current draw and current voltage of the battery. They are usually pretty necessary for Lithium batteries which are quite hard to charge properly without constant intelligent monitoring. Otherwise, when you are experimenting with electronics it's often pretty important to be able to limit the voltage and currents you are applying to avoid putting yourself or your circuits at risk of receiving too much voltage or too much current.

Does Your dc power supply has or support protection short circuit??