Quite often, during testing, you have to power various crafts or devices. And using batteries, choosing the appropriate voltage, was no longer a joy. Therefore, I decided to assemble an adjustable power supply. Of the several options that came to mind, namely: remake a power supply from a computer ATX, or assemble a linear one, or purchase a KIT kit, or assemble it from ready-made modules - I chose the latter.

I liked this assembly option because of undemanding knowledge in the field of electronics, assembly speed, and in which case, quick replacement or addition of any of the modules. The total cost of all components came out to be about $15, and the power in the end turned out to be ~ 100 watts, with a maximum output voltage of 23V.

To create this adjustable power supply you will need:

1. Switching power supply 24V 4A
2. Step-down converter for XL4015 4-38V to 1.25-36V 5A
3. Volt-ammeter 3 or 4 characters
4. Two step-down converters on LM2596 3-40V to 1.3-35V
5. Two 10K potentiometers and knobs for them
6. Two terminals for bananas
7. On/off button and 220V power socket
8. Fan 12V, in my case 80mm slim
9. Corps, whatever
10. Racks and bolts for fixing boards
11. The wires I used are from a dead ATX power supply.

After finding and acquiring all the components, we proceed to the assembly according to the scheme below. According to it, we will get an adjustable power supply with a voltage change from 1.25V to 23V and a current limit of up to 5A, plus the additional ability to charge devices via USB ports, the amount of current consumed, which will be displayed on the V-A meter.

We pre-mark and cut holes for the volt-ammeter, potentiometer knobs, terminals, USB outputs on the front side of the case.

In the form of a platform for attaching modules, we use a piece of plastic. It will protect against an unwanted short circuit to the case.

We mark and drill the location of the holes in the boards, after which we screw the racks.

We fasten the plastic pad to the body.

We solder the terminal on the power supply, and solder three wires to + and -, pre-cut length. One pair will go to the main converter, the second to the converter for powering the fan and the volt-ammeter, the third to the converter for USB outputs.

We install a 220V power connector and an on / off button. We solder the wires.

We fasten the power supply and connect 220V wires to the terminal.

We figured out the main power source, now we move on to the main converter.

We solder the terminals and trimmer resistors.

We solder the wires to the potentiometers responsible for adjusting the voltage and current, and to the converter.

We solder a thick red wire from the V-A meter and the output plus from the main sampler to the output positive terminal.

Preparing USB output. We connect the date + and - for each USB separately so that the connected device can be charged, and not synchronized. Solder the wires to the paralleled + and - power contacts. Wires are better to take thicker.

We solder the yellow wire from the V-A meter and the negative wire from the USB outputs to the output negative terminal.

We connect the power wires of the fan and the V-A meter to the outputs of the additional converter. For the fan, you can assemble a thermostat (diagram below). You will need: a power MOSFET transistor (N channel) (I got it from the processor power supply harness on the motherboard), a 10 kΩ trimmer, an NTC temperature sensor with a 10 kΩ resistance (thermistor) (I got it from a broken ATX power supply). We fix the thermistor with hot glue to the microcircuit of the main converter, or to the radiator on this microcircuit. We adjust the trimmer to a certain temperature of the fan operation, for example, 40 degrees.

We solder to the output plus of another, additional converter plus USB outputs.

We take one pair of wires from the power supply and solder it to the input of the main converter, then the second to the input of the additional one. converter to USB, to provide incoming voltage.

We fasten the fan with a lattice.

We solder the third pair of wires from the power supply to the additional. fan converter and V-A meter. We fasten everything to the site.

We connect the wires to the output terminals.

We fasten the potentiometers to the front side of the case.

We fix the USB outputs. For reliable fixation, a U-shaped mount was made.

Set the output voltage to converters: 5.3V, taking into account the voltage drop when the load is connected to USB, and 12V.

We tighten the wires for a neat interior look.

We close the case with a lid.

We glue the legs for stability.

The regulated power supply is ready.

Video version of the review:

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When designing this power supply, the main goal was to be as portable as possible, and if necessary, you could take with you.

I also have other self-made LBPs, but they are only suitable for stationary use.. This time I decided to use the LM2596 instead of the commonly used LM317 or LM350, to regulate the current.

The beauty of this device is that you can connect it to any 7.5V to 28V DC source. I am using a 19 volt laptop power supply.. The output voltage will be very close to the input voltage, about half a volt less. It can also be used as an unpowered voltmeter, from 2.5V to 30V and as an ammeter . You can also charge the battery with this device, but be careful and watch the current!

Now a little about the assembly of this portable universal LBP

Step 1: Chinese modules and tool:

The basis of all this will be loweringmodule CC-CV LED DC-DC LM2596http://ali.pub/1z01w2

Ammeter with built-in 10 A shunt http://ali.pub/1z029v

Voltmeter (there are different color options for numbers) http://ali.pub/1z02fi

BNS connector + probes http://ali.pub/1z030b http://ali.pub/1z030w

Potentiometers 2 pieces with handles http://ali.pub/1z037p

The rest can be bought at any radio store:

Compact case, can be made of plastic, power input connector, switch, 3 LEDs - different colors.

Tools:

Drill and knife (file)

hot glue

soldering iron

Drills and drills (6mm, 7mm, 10mm)

This simple scheme, it is worth redoing it a little constructively.

The first thing you need to do is to solder the multi-turn trimmers - 2 extreme ones and solder the terminals (or solder the taps from our potentiometers, which will be mounted on the case, for ease of control)

Also, if you do not have a transparent case, you need to bring the LEDs to the front panel of the case. For mounting, it is more convenient to take 3mm or 5mm LEDs.

When charging the batteries, the green LED lights up if the current is less than 0.1 of the set current. This parameter can be adjusted using the middle multi-turn resistor left on the board. This is really not necessary, since you already have a built-in digital milliammeter, and you can see how much current the battery is charging.

This circuit is designed for "3A" but not more (critical load current \u003d 3 A). I ​​recommend adding a radiator to the microcircuit, then the current can be supplied up to 3 A not for a short time.

After adding the radiator, I calmly fed the devices with a current of up to 3 A, the radiator heated up, but not critically.

Secured the radiator with a tie.

This is how the modification of the compact-portable universal LBP \ Power supply turned out.

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Hi all. Everyone involved in electronics should have a . If you are reluctant to solder or you are a beginner radio amateur, this article was written especially for you. Let's talk right away about the characteristics of the power supply and its difference from the popular types of PSUs on the LM317 or LM338.

PSU modules

We will assemble a switching power supply, but we won’t solder anything, we’ll just buy from the Chinese an already soldered voltage regulation module with current limiting, such a module can deliver 30 volts 5 amperes. Agree that not every analog PSU is capable of this, and what losses in the form of heat, since the transistor or microcircuit takes on excess voltage. I don’t write about a specific type of module and its scheme - there are all sorts of them.

Now the indication - here we will not invent anything either, we will take a ready-made display module, as with the voltage control module.

How will you power all this from a 220 V network - read on. There are two ways here.

1. The first is to look for a ready-made transformer or wind your own.
2. The second is to take a pulsed power supply for the desired voltage and current, or modify it to the desired characteristics.

And yes, I forgot to say that you can apply 32 volts to the control module without consequences, but better than 30 volts 5 amperes, you need to be careful with the current too, since the control circuit tolerates 5 amperes, but no more, but it gives everything that is on transformer and therefore burns easily.

PSU Assembly

The assembly process itself is even more interesting. Let me tell you how things are going with my accessories.

• Switching power supply from a laptop 19 volts 3.5 amps.
• Control module.
• Display module.

That's all, yes, yes, I didn't forget to add anything, but we probably still need some kind of old building. I went into business from a Soviet car radio, and any other will do, but I want to separately praise the case from a PC DVD drive.

We assemble our future power supply, before attaching the board to the case, you need to isolate them, I gave a thick film substrate and then all the boards can be attached to double-sided tape.

But when it came to variable resistors for adjusting the voltage and limiting the current, I realized that I didn’t have them, well, not that I didn’t have them at all - there was no required rating, namely 10 K. But they are on the board, and I did the following: I found two burnt variables (so as not to be sorry), removed the handles and thought to solder them to the variables that were on the board, why they were - I soldered them, and tinned the screw.

But nothing happened, I was able to center only when I made this nonsense through heat shrinkage. But she worked, it suits me, and we will find out how long she will work.

If you wish, you can paint the case, I didn’t do it very well, but it’s better than just metal.

The result is a very compact, lightweight laboratory power supply with short-circuit protection, current limiting, and, of course, voltage regulation. And all this is done very smoothly thanks to the multi-turn resistors that were soldered from the control board. The voltage adjustment turned out to be from 0.8 volts to 20. The current limit was from 20 mA to 4 A. Good luck to everyone, I was with you Kalyan.Super.Bos

Discuss the article HOME-MADE POWER SUPPLY ON FINISHED MODULES

I have already done a couple of reviews of a similar thing (see photo). I ordered those devices not for myself, for friends. A handy device for homemade charging, and not only. I also envied and decided to order already for myself. I ordered not only a voltammeter, but also the cheapest voltmeter. I decided to assemble a power supply for my homemade products. Which of them to put was determined only after I assembled the product completely. Surely there will be people who are interested.
Ordered November 11th. There was a small discount. Even though the price is low.
The parcel went for more than two months. The seller gave the left track from Wedo Express. But still the package arrived and everything works. Formally, there are no complaints.
Since it was this device that I decided to implant in my power supply, I’ll tell you a little more about it.
The device came in a standard plastic bag, “bubbled” from the inside.


The item is currently unavailable. But this is not critical. Ali now has a lot of offers from sellers with a good rating. Moreover, the price is steadily decreasing.
The device was additionally sealed in an antistatic bag.

Inside the actual device and wires with connectors.


Key connectors. On the contrary, do not insert.

The sizes are just tiny.

We look at what is written on the seller's page.

My translation with corrections:
- Measured voltage: 0-100V
- Circuit supply voltage: 4.5-30V
- Minimum resolution (V): 0.01V
- Consumption current: 15mA
- Measured current: 0.03-10A
- Minimum resolution (A): 0.01A
Everything is the same, but very briefly, on the side of the product.


I immediately took it apart and noticed that minor details were missing.


But in the previous modules, this place was occupied by a capacitor.

But their price was also different.
All modules look like twin brothers. Connection experience is also available. The small connector is designed to power the circuit. By the way, at a voltage below 4V, the blue indicator becomes almost invisible. Therefore, we follow the technical characteristics of the device, we do not supply less than 4.5V. If you want to use this device to measure voltages below 4V, you need to power the circuit from a separate source through a “thin wire connector”.
The current consumption of the device is 15mA (when powered by 9V "crown").
Connector with three thick wires - measuring.


There are two accuracy controls (IR and VR). Everything is clear in the photo. Resistors are dark. Therefore, I do not recommend twisting it often (you will break it). The red wires are the leads for voltage, the blue ones are for current, the black ones are “common” (connected to each other). The colors of the wires correspond to the color of the glow of the indicator, do not get confused.
The head chip is unnamed. It once was, but it was destroyed.


And now I will check the accuracy of the readings using the exemplary installation P320. I applied calibrated voltages 2V, 5V, 10V, 12V 20V, 30V to the input. Initially, the device underestimated by one tenth of a volt at certain limits. The error is insignificant. But I adjusted myself.


It can be seen that it shows almost perfectly. Adjusted the right resistor (VR). When the trimmer is rotated clockwise, it adds, when rotated counterclockwise, it decreases the reading.
Now I'll see how it measures the current strength. I power the circuit from 9V (separately) and supply an exemplary current from the P321 installation


The minimum threshold from which it starts to correctly measure the current is 30mA.
As you can see, the current measures quite accurately, so I won’t turn the adjusting resistor. The device measures correctly even at currents greater than 10A, but the shunt starts to heat up. Most likely, the current limit is for this reason.


At a current of 10A, I also do not recommend driving for a long time.
More detailed calibration results are summarized in a table.

I liked the instrument. But there are shortcomings.
1. The inscriptions V and A are painted, so they will not be visible in the dark.
2. The instrument measures current in one direction only.
I would like to draw attention to the fact that it would seem that the same devices, but from different sellers, can be fundamentally different from each other. Be careful.
On their pages, sellers often publish incorrect connection diagrams. In this case, there are no complaints. That's just a little of it (scheme) changed to a more understandable eye.

With this device, in my opinion, everything is clear. Now I'll tell you about the second device, about the voltmeter.
I ordered on the same day, but from a different seller:

Bought for US $1.19. Even with today's exchange rate - funny money. Since in the end I did not install this device, I will go through it briefly. With the same dimensions, the numbers are much larger, which is natural.

This device does not have a single tuning element. Therefore, you can only use it in the form in which it was sent. Let's hope for Chinese good faith. But I'll check.
The installation is the same P320.

More details in the form of a table.


Although this voltmeter turned out to be several times cheaper than a voltammeter, its functionality did not suit me. It does not measure current. And the supply voltage is combined with the measuring circuits. Therefore, it does not measure below 2.6V.
Both devices are exactly the same size. Therefore, replacing one with another in your homemade product is a matter of minutes.


I decided to assemble the power supply on a more universal voltammeter. The devices are inexpensive. There is no burden on the budget. The voltmeter is still in stock. The main thing is that the device is good, and there will always be an application. Just from the store and got the missing components for the power supply.
I have been idle for several years now with such a set of homemade.

The scheme is simple but reliable.

It is pointless to check the completeness, a lot of time has passed, it is too late to make claims. But everything seems to be in place.

The trimmer resistor (complete) is too dumb. I see no point in using it. Everything else will fit.
I know all the disadvantages of linear stabilizers. I have neither the time, nor the desire, nor the opportunity to fence something more worthy. If you need a more powerful power supply with high efficiency, then I'll think about it. Until then, what has been done.
First I soldered the stabilizer board.
I found a suitable case at work.
I rewound the secondary of the torroidal trance to 25V.


Picked up a powerful radiator for the transistor. All this stuffed into the body.
But one of the most important elements of the circuit is the variable resistor. I took a multi-turn type SP5-39B. The output voltage accuracy is the highest.


Here's what happened.


A little unsightly, but the main task is completed. I protected all electrical parts from myself, I also protected myself from electrical parts :)
It remains to "retouch" a little. I will paint the case from a spray can and make the front panel more attractive.
That's all. Good luck!

I watch a lot of videos on repairing various electronics and often the video begins with the phrase "connect the board to the LBP and ...".
In general, the LBP is a useful and cool thing, it just stands like an airplane wing, and I don’t need accuracy in fractions of a millivolt for crafts, it’s enough to replace a bunch of Chinese PSUs of dubious quality, and be able to determine how much power the device needs without fear of burning something lost PSU, connect and increase the voltage until it works (routers, switches, laptops), and the so-called "Troubleshooting using the LBP method" is also a handy thing (this is when there is a short circuit on the board, but you will understand which of the thousands of SMD elements the horseradish has broken through, to the inputs LBP clings with a current limit of 1A and a hot element is searched for by touch - heating = breakdown).

But because of the toad, I could not afford such a luxury, but crawling along Pikabu I came across an interesting post that says how to assemble the PSU of your dreams from shit and sticks of Chinese modules.
After digging more on this topic, I found a bunch more videos on how to collect such a miracle Once Two.
Anyone can assemble such a craft, and the cost is not so expensive compared to ready-made solutions.
By the way, there is a whole album where people show off their crafts.
I ordered everything and started to wait.

The basis was a pulsed power supply unit 24V 6A (the same as in the soldering station, but about it next time)

The voltage and current regulation will go through such a converter - a limiter.

Well, the indicator is up to 100 volts.

In principle, this is enough for the circuit to work, but I decided to make a full-fledged device and bought more:

Power connectors for cable "eight"

Front panel banana plugs and 10K multi-turn resistors for smooth adjustment.
And I also found drills, bolts, nuts, hot-melt glue in the nearest construction store and tore out a CD drive from the old system unit.

To begin with, I collected everything on the table and tested it, the circuit is not complicated, I took it

I know that these are screenshots from YouTube, but I'm too lazy to download videos and cut frames from there, the essence of this will not change, but I could not find the source images now.

The pinout of my indicator was found in Google.


I assembled and connected the light bulb for the load, it works, I need to assemble it into a case, I have an old CD drive as the case (probably also a working one, but I think it’s time for this standard to rest) the drive is old, because the metal is thick and durable, the front panels are made of plugs from the system.

I figured out what and where it would fit in the case, and the assembly began.

I marked out the places for the components, drilled holes, painted the cork from the balloon and inserted the bolts.

Under all the elements, I glued the plastic from the packaging of the headphones to avoid a possible short circuit to the case, and under the DC-DC converters for USB power and cooling I also put a thermal pad (by making a cutout in the plastic under it, after cutting off all protruding legs, I took the thermal pad itself from the drive, it cooled the motor driver).

From the inside, I screwed one nut each and cut a washer from the plastic container on top to raise the pallets above the body.

I soldered all the wires, since there is no faith in the clamps, they can loosen up and start heating up.

To blow through the hottest elements (Voltage Regulator), I installed 2 40mm 12V fans in the side wall, since the PSU does not heat up all the time, but only under load, I don’t really want to constantly listen to the howl of not the quietest fans (yes, I took the cheapest fans, and they make noise strongly) to control the cooling, I ordered such a temperature control module, the thing is simple and super useful, you can both cool and heat, it’s easy to set up. Here is the instruction.

I set it to about 40 degrees, as the hottest point was taken by the radiator of the converter.

In order not to drive excess air, I set about 8 volts on the cooling power converter.
As a result, something like this turned out, inside the place in bulk, you can add some kind of load resistor.

Already under the final view, I ordered twisters, I had to cut off 5mm of the resistor shaft and put 2 plastic washers on the inside so that the handles became close to the case.

And that we have a completely suitable PSU, with an additional USB output that can give 3A to charge the tablet.

This is how the PSU looks already on rubber legs (3M Bumpon Self-Adhesive) paired with a soldering station.

I am pleased with the result, it turned out to be quite a powerful power supply unit with smooth adjustment and at the same time light and portable, I sometimes work on the road and carrying a factory LBP with a toroidal transformer is not a thrill at all, but here it fits quite easily in a backpack.

I will tell you about how I made the soldering station next time.