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. :)
marlasota I'm not an electrical expert so I was wondering how the unit "knew" not to output more than 900Ma into the light. All other videos on these types of power supplies advice to preset your max amp output before hand so I was confused when the guy in the video didn't do that. I would still preset my amp output when working on cell phone/tablet boards just to be safe.
it's reactionary. the knobs set the max current you'd like to provide, when the output current is sensed at or beyond that value it starts cutting the voltage back. the displays don't show the potential output (set with knobs) but only show the actual output. probably an analog circuit using op-amps. just ordered one to play with myself. I expect it'll explode in my face.
@R-77So how do your light bulbs in your home know they they are only 60 watts and don't trip your circuit breaker mains? Obviously they are designed to have a certain resistance to have the correct wattage consumption at the rated voltage. Watts = Volts x Amps & Voltage = Amps x Ohms.
@@robc8468 the load doesnt 'know' how much amperage it needs. This power supply requires you to set max current as well as max voltage before you connect it to your load. He only showed setting max voltage to 12v in the video. Idk why he said it was protection
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.
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.
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?
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 .😊
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.
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!
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
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)
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....
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.
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.
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? ? ?
@@remu3881 they wouldn't even take it back eva but ive got rid of it now anyway iam useing a lap top charger for zinc plating now but thanks for the reply anyway mate
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.
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?
Double check all the connecting posts on this power supply from inside the unit. Mainly make sure tight and secured. This will cause no output which is a common problem on these power supply.
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!
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.
PROTOCỢL watch out, I just order one, and fail. I do not recommend. Looks like never have been tested before shipping. Mine shows only zeros but it does not regulate.
Well, I already bought it and we'll see.. I'm going to buy a much better one with more accuracy next week, so I'm just gonna test this and use it for rough powering.
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
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. :-)
I have a question ,for protect for example laptop Mainboard when we want to find short on mainbord, just i need set manually amps on 1 amps and then iam protect the circuit??
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.
+Burger Birger Still works fine and don't have a scope to check how clean it is. Not too important for the things I do to test some basic electronic circuits.
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?
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
+Alb_ALPS There is a controller board in the power supply that might be having issues. You can open it and take a quick look, but it can be challenging to fix.
+dial2fast thanks, i had it hooked up to a fantom load and i wonder if the overload protection kicked in or burned out... i shall try to fix as not easy to get warrantee from China...
+Alb_ALPS Hi, my power supply has also died upon switching on with no load attached. There seems to be no sign of life and both fuses are okay. Did you figure out what was the cause of your unit's fault.
Is it a problem running this power supply at 10amps for over 2 hours, like wires getting really hot. I was thinking about using this for anodizing aluminum with constant current.
These are rather budget power supplies. By using it at its maximum rating for long periods of time, it may shorten the life of the unit. Really hard to say.
Eric Smith These cheaper power supplies will only give you the maximum rated power and don't often tell you the constant rated power in the advertisement so it can probably only run at 10 amps for short periods, its probably safe to say the constant rated current is around 6 amps as they normally give power supplies a rated power of a third lower than the max rated.
i would recommend using a PC power supply (PSU) its a cheaper option or you might already have an old one you could use and it works very well i use mine all the time with no problem
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?
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 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?
dial2fast a computer hard drive uses a strong magnet to position the swing arm. very nice magnets, will actually jump out of your hand to stick to your stove or fridge.
@@hotcana Wow I have been tearing down hard drives now for years to collect those magnets. The largest I ever found was a very old SCSI 4 GIG, those magnets could crush a fellows finger if you had it between them and they found each other! Gave one to my cousin to use in his small engine repair facility, he loves it, says it has saved him hours of search time when he drops a screw in the dirt, the magnet will pick it up within 5 inches!
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. :)
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.
King Parodije good lucky. Mine it didn't work. Shows the display, but the control knob button for the settings up or Down, remains in ceros. Then when I turn of, startups for a second then die my 12 v motor.
this one has a voltage spike when turning on. you have first to turn the supply on, and then connect the motor. I hope mine will be fine. Will let you know.
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
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
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.
Aaron Chamberlain I bought one of the yescom power supplies off of Newegg a couple weeks ago. The first didn't work, so I requested a replacement, and they sent it free of charge. It doesn't work either. Hopefully the third time's the charm, and they don't try and make me spend all the savings I thought I was getting on shipping.
They all had slightly different sets of problems. The first two, the knobs wouldn't turn the power up. No reading when checked by my multi-meter, so it wasn't just the display, either. The third worked intermittently for a bit less than a minute, with no load, fresh out the box. Then only the voltage regulation worked, with a very very small amperage reading. It failed before I even attached it to anything. I'm trying to get a refund now, but Yescom isn't responding, and now I'm past the 30 day return period. Newegg said they'll talk to them, and to wait a couple days for a response. I don't want to pay to ship all three of these back to the California warehouse they came from, either, to get my 50 bucks back. (I think they knocked it up to the 60 you paid right after I bought mine, btw.)
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.
***** The power supply will always try to output the proper current draw that your device requires. So if the load needs 1amp, and you set it for 2amp, it will still output the required of 1amp.
I have the same problem, annoying because i thought I would be able to adjust current while keeping voltage the same for zinc plating. I thought that was the point of a variable power supply!
Ohms law explains why as you decrease current, voltage drops, Ohms law is "Voltage = Current x Resistance". in your electrolysis tank the resistance doesn't change, but if you raise or lower current, the voltage will change. With any power supply you cannot put more current into a circuit without either raising voltage, or reducing resistance. if you need more current, look at thicker wires, and better/more terminations to reduce resistance. or raise the voltage. if you wish to reduce current, you will have a loss in voltage.
so lets say i have a 12 volt fan and i want to find what spin rate i want to use it. the higher the amp on my power supply will make the fan spin faster. so 1 power supply at 12 volts 1 amp will spin slower then if i put a 12 volt 2 amp power supply. So this power supply will not give me that option to increase the amps unless i raise the voltage. Is that correct???? My thing is like @dialfast i want to adjust the amps while keeping the volts the same. I also purchased this because i was thinking i would be able to adjust both volts and amps. My thing was this way i can find what combination volts and amps power supply i can purchase and save me the guessing game what will work best.
I have the same unit. it arrived with a piece of sheet metal between ground and the negative terminal. some units don't have that. is that peace supposed to be there? the manual fits not reference it. thnx
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.
It is recommended that you charge each battery at a fixed current until it reaches 1.5V or so. By charging individually, the charger can determine through temp rise and how quickly the voltage is rising, when to stop charging. When you have a number of batteries hooked up in series and parallel, you deprive the charging process of this information, and it is up to you when to stop. Problems arise when not all the individual batteries are at the same state of charge at the start of charging, and they will accept charge at different rates. So let's say you charge your pack at 10A, and watch the voltage rise to 13.5 V. Some of the batteries will be undercharged still, while others may be overcharged. Repeat this a few times and differences between batteries will be magnified to the point of hazard. You can find more info at batteryuniversity.com. Commercial battery packs are built with cells that have been matched, but even then failures do occur. But if you want to try anyway, set the voltage to 13.5V and current control to 10A. The charge time is determined by how discharged the batteries are. If you determine they are 50% discharged, then 33.3 Ah needs to be replaced (this will undercharge a little, to be safe), so you would charge for 3 hrs 20 min. if the current was constant at 10A. But it won't be, as the voltage rises the charging current will fall off. So you have another margin against overcharge if you stick to the calculated time. Be sure to be on the lookout for individual batteries that may be getting hot, by feel or infrared thermometer. If so, stop the charging and remove that string from the pack and charge the rest. Then go back to the problem string and see what you can do to fix it.
cats and dogs in a bag tied to my truck if you can see the piece of metal which is already connecting the ground and negative terminals by default. in most cases you probably want an earth wire connected, but that piece of metal can usually be removed if a floating ground is needed, or could be positive earth in special cases.
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.
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. :)
+Brian Gilbert Cool. Thanks for your comment!
luil
the 900mA is NOT current protection but rather the Ohm's law.
marlasota I'm not an electrical expert so I was wondering how the unit "knew" not to output more than 900Ma into the light. All other videos on these types of power supplies advice to preset your max amp output before hand so I was confused when the guy in the video didn't do that. I would still preset my amp output when working on cell phone/tablet boards just to be safe.
it's reactionary. the knobs set the max current you'd like to provide, when the output current is sensed at or beyond that value it starts cutting the voltage back. the displays don't show the potential output (set with knobs) but only show the actual output. probably an analog circuit using op-amps. just ordered one to play with myself. I expect it'll explode in my face.
@R-77So how do your light bulbs in your home know they they are only 60 watts and don't trip your circuit breaker mains? Obviously they are designed to have a certain resistance to have the correct wattage consumption at the rated voltage. Watts = Volts x Amps & Voltage = Amps x Ohms.
@@robc8468 the load doesnt 'know' how much amperage it needs. This power supply requires you to set max current as well as max voltage before you connect it to your load. He only showed setting max voltage to 12v in the video. Idk why he said it was protection
lol i just came here to say that, if the load only draws 900mA you can't magically toss 10 amps at it
Just bought one of these and this was a great explanation of how to use this power supply. Thank you.
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.
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 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.
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?
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 .😊
Hi sir how much minimum voltage you can get from power supply
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.
I have this exact PS and needed to get your input to keep from hurting myself. Thanks. Subbed.
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.
Thanks for sharing! Nice explanation of how to use the constant current feature.
Can you charge laptop batteries using your dc power supply.
Very detailed great job explaining how the amps work!
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!
Did you buy the unit? How's it going?
WHY DID YOU NOT CONNECT AN AMMETER IN SERIES WITH THE CIRCUIT?
Thank you. For your knowledge and the understanding I received, Randy Bentley
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
Great explanation and video, wish I'd found it a few years back.👍👍👍
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)
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....
Wonderful video, clear and concise. Keep it up
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.
Sir can we use this for laptop repair ?
So ive got this 15v model how to icrease it to 24v since it has a 24 v output transformer
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.
Just what I needed! Thank you!
A review of a 10A PSU with just 1A ???
Excellent but do you calibrated you new lead resistance to your power supply
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? ? ?
I think you you need just plain psu with big transformer inside and not switching psu for the job
@@remu3881 they wouldn't even take it back eva but ive got rid of it now anyway iam useing a lap top charger for zinc plating now but thanks for the reply anyway mate
@@officialmysteriousrider6327 that's all good mate keep safe 👍
What if I need to go more amps on this device, how can I do this?
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?
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.
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
what is the "ground" for on the dc output?
What is the purpose of the strip of metal between the ''Negative'' and ''Ground'' and will it cause any problems if I remove it?
It ties the negative pin to ground. That meaning your sockets ground. If you remove it you can use the power supply as a floating voltage source.
Pavetski Ok, thanks :)
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?
Double check all the connecting posts on this power supply from inside the unit. Mainly make sure tight and secured. This will cause no output which is a common problem on these power supply.
@@dial2fast Thanks, I will take the cover off again and give it another look. Do the pots tend to go bad on these?
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!
Yes it will work as a power supply for your LED circuit in a breadboard.
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.
PROTOCỢL watch out, I just order one, and fail. I do not recommend. Looks like never have been tested before shipping. Mine shows only zeros but it does not regulate.
Well, I already bought it and we'll see.. I'm going to buy a much better one with more accuracy next week, so I'm just gonna test this and use it for rough powering.
would you recommend a powersupply like this for charging lipo batteries?
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
I see a small two potentiometer between the led display and the volt and current potentiometers .. what is that small potentiometer for ?
Probably to zero the meters.
try this,,, set to 10v,,, set to 0.5a,,,,,, now short output,,,, what happens... what readings,,, pls
Current reads 0.9A, voltage reads 0.1V
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. :-)
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
Thanks for the video. It helped me out with the problem I was having with mine.
It help a lot, thanks. You never said what the yellow button was for that sits between the back and red power button.
that's just an earth clamp
+wayne murphy thanks - very helpful.
Does Your dc power supply has or support protection short circuit??
Yes it does
@@dial2fast what do you think about ,linear dc power supply?is it good??
I have a question ,for protect for example laptop Mainboard when we want to find short on mainbord, just i need set manually amps on 1 amps and then iam protect the circuit??
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.
+Vallen Larsen No
really nice demo. thank you so much. I have already destroyed many component.
Good Video. Can you do a short circuit test on these psu's? Eg. 200mA at 1.5V with output leads shorted.
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.
Jerry Ericsson verdict?
Hi, great review. Does it drop to 16-18 volts when you drawing high current like 9-10 amps?
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.
+Burger Birger Still works fine and don't have a scope to check how clean it is. Not too important for the things I do to test some basic electronic circuits.
Ok, thanks :)
Hi i want to ask you if everything is solved by eletronic or inside is transformator
There is a transformer with multiple secondary taps.
This is a fantastic power supply thanks for the link i will consider
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?
Joe Li mine just did that as well.
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
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
+Alb_ALPS There is a controller board in the power supply that might be having issues. You can open it and take a quick look, but it can be challenging to fix.
+dial2fast thanks, i had it hooked up to a fantom load and i wonder if the overload protection kicked in or burned out... i shall try to fix as not easy to get warrantee from China...
+Alb_ALPS Hi, my power supply has also died upon switching on with no load attached. There seems to be no sign of life and both fuses are okay. Did you figure out what was the cause of your unit's fault.
Is it a problem running this power supply at 10amps for over 2 hours, like wires getting really hot. I was thinking about using this for anodizing aluminum with constant current.
These are rather budget power supplies. By using it at its maximum rating for long periods of time, it may shorten the life of the unit. Really hard to say.
Eric Smith These cheaper power supplies will only give you the maximum rated power and don't often tell you the constant rated power in the advertisement so it can probably only run at 10 amps for short periods, its probably safe to say the constant rated current is around 6 amps as they normally give power supplies a rated power of a third lower than the max rated.
just got 2 of these one broken cheers for the heads up :)
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
i would recommend using a PC power supply (PSU) its a cheaper option or you might already have an old one you could use and it works very well i use mine all the time with no problem
and how do you regulate the voltage ?
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?
The knobs are fine and coarse adjustments
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?
Yes still working great!
Amazing explanation. I was searching for it from long time.
What a in complete explanation
They didn't explain ed how to connect apparatus correct ly. That's bad
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?
You ay need to open it up and adjust one of the trim POTs. The factory must have set yours a touch too low.
Gr@ssoft, did you diagnose problem? Was it bridge rectifier?
The crooked label that is lifting of the panel is pretty funny.
i could not leave a comment on the hard drive one, are there not circular magnet in there some where
I am not aware of any magnets in the hard drive. The only thing with a magnet may be the brushless motor.
dial2fast a computer hard drive uses a strong magnet to position the swing arm. very nice magnets, will actually jump out of your hand to stick to your stove or fridge.
+Stephen Surls Thank you! I found them in a old 12 GB and stronger ones inn a 60 GB drive ! Glad I never did trow them in the garbage
+dial2fast That are the round one's. More like rings.
@@hotcana Wow I have been tearing down hard drives now for years to collect those magnets. The largest I ever found was a very old SCSI 4 GIG, those magnets could crush a fellows finger if you had it between them and they found each other! Gave one to my cousin to use in his small engine repair facility, he loves it, says it has saved him hours of search time when he drops a screw in the dirt, the magnet will pick it up within 5 inches!
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. :)
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.
dude, did you test the max. 10 A specification ? you did only 0.9 A ?
I did not test the full 10A output. Most of the bench testing I do runs no more than about 7A.
King Parodije it's a crap. Don't buy it.
Soy ketzatkoatl why is it crap. I have already purchased one
King Parodije good lucky. Mine it didn't work. Shows the display, but the control knob button for the settings up or Down, remains in ceros. Then when I turn of, startups for a second then die my 12 v motor.
this one has a voltage spike when turning on.
you have first to turn the supply on, and then connect the motor.
I hope mine will be fine. Will let you know.
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
Aren't the phones just pinging the tower when on standby and not on full time broadcast mode?
Mine has an issue where it has trouble regulating below 300mA. Does yours?
I don't have the problem.
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
How can I use 12v with 1 amp ?
Yes
@@dial2fast my power supply gave only 0.20 amp please help
Nice video sir.. Thank you for knowledgeable video
Great vedio Sir it's very clear.... 👍
I really do not know whether I should make my own power supply or buy like that. Obviously fan sound disturbs me..
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.
Aaron Chamberlain I bought one of the yescom power supplies off of Newegg a couple weeks ago. The first didn't work, so I requested a replacement, and they sent it free of charge. It doesn't work either. Hopefully the third time's the charm, and they don't try and make me spend all the savings I thought I was getting on shipping.
Dalton Patterson what exactly didn't work about it? Mine powered on just fine and I used it in place of a 9V battery as a test. Worked fine for me.
They all had slightly different sets of problems.
The first two, the knobs wouldn't turn the power up. No reading when checked by my multi-meter, so it wasn't just the display, either. The third worked intermittently for a bit less than a minute, with no load, fresh out the box. Then only the voltage regulation worked, with a very very small amperage reading. It failed before I even attached it to anything.
I'm trying to get a refund now, but Yescom isn't responding, and now I'm past the 30 day return period. Newegg said they'll talk to them, and to wait a couple days for a response. I don't want to pay to ship all three of these back to the California warehouse they came from, either, to get my 50 bucks back. (I think they knocked it up to the 60 you paid right after I bought mine, btw.)
Nice sir, its knowledge video.... Thanks sir.
Thank you for this!
Great Video, It helped me alot, Thanks
Very helpful video thank you 😀
Why is the earth and negative shorted
cuz that's a normal use case. that piece of metal is usually optional and can be removed if there's some need to do so.
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.
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.
***** The power supply will always try to output the proper current draw that your device requires. So if the load needs 1amp, and you set it for 2amp, it will still output the required of 1amp.
I have the same problem, annoying because i thought I would be able to adjust current while keeping voltage the same for zinc plating. I thought that was the point of a variable power supply!
Ohms law explains why as you decrease current, voltage drops, Ohms law is "Voltage = Current x Resistance". in your electrolysis tank the resistance doesn't change, but if you raise or lower current, the voltage will change.
With any power supply you cannot put more current into a circuit without either raising voltage, or reducing resistance. if you need more current, look at thicker wires, and better/more terminations to reduce resistance. or raise the voltage. if you wish to reduce current, you will have a loss in voltage.
so lets say i have a 12 volt fan and i want to find what spin rate i want to use it. the higher the amp on my power supply will make the fan spin faster. so 1 power supply at 12 volts 1 amp will spin slower then if i put a 12 volt 2 amp power supply. So this power supply will not give me that option to increase the amps unless i raise the voltage. Is that correct???? My thing is like @dialfast i want to adjust the amps while keeping the volts the same. I also purchased this because i was thinking i would be able to adjust both volts and amps. My thing was this way i can find what combination volts and amps power supply i can purchase and save me the guessing game what will work best.
Did you pay $200 for it on eBay or did you make an offer?
I paid like $86 on Ebay and I think it was Buy It Now from a California seller.
Thanks very good information , after your i have learn new stuff
+muhammed hussain ali Glad you found my video helpful
I have the same unit. it arrived with a piece of sheet metal between ground and the negative terminal. some units don't have that. is that peace supposed to be there? the manual fits not reference it. thnx
I know it has a functional purpose, but I do not know what it is.
The current can't go higher because the blulb is only 900 ma of r
This is the video I was looking for, god dammit!.
Think about Ohm's law! You missed something!
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.
It is recommended that you charge each battery at a fixed current until it reaches 1.5V or so. By charging individually, the charger can determine through temp rise and how quickly the voltage is rising, when to stop charging. When you have a number of batteries hooked up in series and parallel, you deprive the charging process of this information, and it is up to you when to stop. Problems arise when not all the individual batteries are at the same state of charge at the start of charging, and they will accept charge at different rates. So let's say you charge your pack at 10A, and watch the voltage rise to 13.5 V. Some of the batteries will be undercharged still, while others may be overcharged. Repeat this a few times and differences between batteries will be magnified to the point of hazard. You can find more info at batteryuniversity.com. Commercial battery packs are built with cells that have been matched, but even then failures do occur. But if you want to try anyway, set the voltage to 13.5V and current control to 10A. The charge time is determined by how discharged the batteries are. If you determine they are 50% discharged, then 33.3 Ah needs to be replaced (this will undercharge a little, to be safe), so you would charge for 3 hrs 20 min. if the current was constant at 10A. But it won't be, as the voltage rises the charging current will fall off. So you have another margin against overcharge if you stick to the calculated time. Be sure to be on the lookout for individual batteries that may be getting hot, by feel or infrared thermometer. If so, stop the charging and remove that string from the pack and charge the rest. Then go back to the problem string and see what you can do to fix it.
what happens if we short gnd and - terminal together....?
cats and dogs in a bag tied to my truck
if you can see the piece of metal which is already connecting the ground and negative terminals by default. in most cases you probably want an earth wire connected, but that piece of metal can usually be removed if a floating ground is needed, or could be positive earth in special cases.
What is the price?
Got it for $80 2 years ago on Ebay
dial2fast is this for laptop repair
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.
Good information thanks sir
My QW-MS305D dc power supply is mess up FUCK.I Miss my dc power supply.
Thanks very informative