Help. info about Adjustable Step-Down Voltage Meter Power Supply Module: "WZ5012L"

@man77 Now I am going to let Dave @davee educate you re grounding that you mentioned at 

https://forum.dronebotworkshop.com/tools-equipment/help-info-about-adjustable-step-down-voltage-meter-power-supply-module-wz5012l/#post-45030

@davee Ok ok I understand 🙂 

@zander Ok, I'll study all your explanations calmly, and I'll update you if I don't explode together with the power supply 🤣

@man77 Follow Bills example at https://dronebotworkshop.com/atx-bench-supply/ and the video at

Hi  Ron @zander and @man77,

   Sorry, I don't know where you discovered the WZ converter is buck-boost.

The information I found, and also the last reference (now available) provided by Manuel says:

That sounds like Buck only to me!! In which case, my previous comments are still true - voltage out will ALWAYS be less than the input.

If my observation from available information that the WZ device is Buck-only is correct, then any 'normal' ATX power supply will not meet any requirements over about 10V.

So I think an ATX supply is a non-starter for your requirements. The WZ device is only likely to meet your stated expectations if driven by a supply capable of about 35V at (greater than) 10 A.

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Manuel wrote: Ok ok, I only need it to power and test notebooks, smartphones, household appliances (logic boards), in the near future. For me, 30 volts max and 5 or max 10 amps would be enough. I would need it to see if there are short circuits (therefore to see the absorption of the broken logic boards,
short circuits. 

By Notebooks, I assume you mean Laptops. In my (limited) experience, these typically need 19 to 20 V external power, though I expect there are exceptions.

Smart phones are often 5V, though increasingly support the 'negotiable' USB-C voltages that start at 5V, but can negotiate higher voltages.

Household appliances could mean anything, though I would expect 3.3V and 5V to be common logic choices, but often including higher voltages to drive motors, etc. Of course, household equipment is often made in huge quantities, so devices designed for a specific purpose, with unusual power requirements will probably appear.

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For the notebooks/laptops, assuming you are expecting to fix a lot in the future, maybe as a business, I would be inclined to assemble a supply specific for the purpose. No guarantees, but this would reduce the chance of you accidentally destroying a 'fixable' machine due to an overvoltage spike, etc., and cover the issues of every machine (apparently) having a different plug.

Initially that might even be one of the 'generic replacement' laptop power supply units with maybe 20 different power plug designs, and some switchable voltages in the range around 20V. Add a replaceable fuse and voltage/current meter into the wire to cover for short circuits and watch for problems.

 You could also include a simple variable current limit, based on a power transistor or two.

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Smartphones are usually USB based, and increasingly that means USB-C, with its 'smart' voltage changes. A 'simple' 5V supply might be enough for some purposes, but increasingly I think you will need to check the voltage change stuff as I predict many problems will be due to damage around the USB-C socket.

So again, a dedicated solution is probably a longer term requirement. In the meantime, maybe a 5V USB with one of the power monitor units and a range of plugs is probably a safer approach.

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Household equipment is clearly a tricky one. Not only because the voltages can be almost any value you can think of, but also from a safety viewpoint, they are often connected directly to the mains.

At the risk of sounding a pessimist, I would suggest that this is a hazardous area if you are near the beginning of your learning curve. Of course, some items, like an electric toothbrush may come with a separate low voltage supply unit, so there is no risk of shock inside the unit, if it is a battery powered toothbrush, but many items, such as a washing machine, or a TV, in which the power supply in internal, can be very hazardous.

For the low voltage cases, a variable power unit such as that described by Bill (@dronebot-workshop) is a good starting point. This would probably also fit in with any general development projects of your own.

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Sorry, this is probably not the sort of answer you are hoping for, and it assumes some guesses on my part, which may not be valid, so please take time to consider your specific needs. The above suggestions are given in good faith, but only you know about your needs, so all of the responsibility remains with you.

Best wishes and good luck with your projects, Dave

@davee Yes, notebook (that's what we call them in Italy) is Laptop. After all these explanations of yours I understood that it is not a good project to make a bench power supply with that WZ that I purchased and a computer power supply. I'm afraid it may cause damage to the equipment. I'm considering returning the WZ and purchasing a benchtop linear power supply. I'll update you soon. You were all really kind. You are good people. Sorry for my bad English

@man77 Your English is fine. You can still make a switching supply with the ATX, just follow the article I already sent you. OR if you want a linear then Bill also did one of those. Here is the link

https://dronebotworkshop.com/linear-dc-power/

The 'trick' is getting the right transformer. You will need to understand RMS but for a shortcut, get a transformer with 16VAC on the secondary with 2.5A to 3A

You also may want to look at the following, this is where I used the similar variable with meter as yours https://dronebotworkshop.com/simple-supply/#Parts_List video at

@zander Ok, I'll see if I can get a transformer with 16VAC and I'll update you 🙂. Thank you so much 🙂

@man77 That is just one part, there is a bunch more. Follow Bills article and source all the parts first. I don't know what it's like in Italy to do that, but it's a problem here in Canada. Deciding on what transformer will influence the box to hold everything so think first, act later, much later.

@zander Ok, I will try to get all the components, if I can find them and I will do everything calmly, studying your explanations and watching Bill's videos on Youtube. Perfect 👍 🙂

@man77 The videos are what I call eye candy, the associated article (click ...more under the video and the first link is the article) is the lesson material.

Hi @man77,

   Returning the WZ device and starting along the lines of Bill's design sounds like a good plan. In reality, you might be able to buy a ready-built supply for roughly the same cost (direct from China), but building it yourself will be a great learning exercise.

I suggest you use it to try out some circuits using Arduinos, ESP32s and so on, using examples kindly and expertly provided by Bill. There is an 'art' to fixing commercial equipment, and obviously a potential source of income, but a lot of the jobs will be repetitive things like broken sockets, exhausted batteries, etc., which provide the most reliable income but can be a bit boring, and you may not learn much. So look to expand your knowledge with some other construction projects, and you will also learn some skills that will be useful when doing the 'tricky' repairs.

By the way, your English is fine, so don't worry about that.

I wish you all the best for 2024 and beyond, Dave

@davee Thanks for this advice on Arduino ESP32. In reality I don't have any Arduino model (which if I'm not mistaken was invented in Italy), I've seen that the Arduino ESP32 also costs little. Anyway, thanks to your suggestion and Bill's examples, I will consider the purchase. Yes, I like electronics at 360 degrees, and not just to try to repair logic boards etc., but to expand my knowledge. Anyway, after all this wonderful advice of yours, it will be my obligation to update you on my progress in electronics 🙂 . Thanks Dave, I really respect people who don't keep their knowledge to themselves. I really hope one day to be able to help someone with their first experience in electronics, as you are doing with me, directing me slowly and with great kindness. You are a beautiful family in this forum. I am very excited by all these explanations, I did not expect to receive all this courtesy. in Italian forums they are not as patient and courteous as you...

Hi @man77,

 Thanks for your kind reply.

Arduino does indeed originate in Italy, from a company that shares its designs with the rest of the World. Such sharing inevitably means that it is heavily copied and cloned by others who undercut its price, but such cloning also establishes the designs as de facto standards, so that although they lose some business to the competition, they probably gain from larger volume customers who incorporate the Arduinos into their own products, and who would be unwilling to compromise their reputation by buying from less well-known clone sources who might supply poor quality product, whilst knowing they probably have 'second sources' available as a last resort.

The majority of ESP32 based boards do not come from Arduino, but due to work by Espressif, the ESP chip manufacturers, and many others, the Arduino IDE is one programming option, meaning that many programs originally aimed at an Arduino board can also be ported to an ESP32. Similarly, other boards like the Raspberry Pi family can also be programmed using the Arduino IDE.

Good luck with your progression ... I am sure you will soon be in the position to share some of your own findings ... may be starting with your power supply ... I am pretty sure Bill would appreciate an article describing how you used his work as an inspiration for your variant.

Best wishes for 2024, Dave

@man77 Arduino is indeed Italian, and ESP32 is Chinese. The Arduino IDE can build code for both families of chip. Most beginners start with an Arduino UNO Rev 3 kit such as https://amz.run/7b3t

There are probably a dozen kits like this and almost any will do as a starter.