Bestrazing power supply unit 12 volts with your own hands at home

Sometimes a low-voltage current source is required to connect various instruments. Models implemented in stores have large dimensions and weight due to a lowering transformer, which is included in their composition. For some devices, these parameters may be critical, so more and more often users prefer to assemble the bats for 12 volts with their own hands.

Fitness of the Power Block in everyday life

Each in the house has different equipment that works from batteries or batteries. In order not to change each time the items are powered by any source connected to 220 V.

High power from a fully used non-informator small-sized block should not be waited. Rechargeable tools (screwdrivers, drills, disk saws), pumps, tablets and laptops will not work from it.

To such a BP, you can connect lighting and electronic techniques that consume a current of up to 500 mA:

  • small-sized receivers;
  • LED bulbs and garlands (but not tapes);
  • portable low-power medical equipment (wrist tonometer, pulse meter and other parameters);
  • Charging modules of phones;
  • Kids toys;
  • Motors of tape recorders, fans;
  • homemade devices;
  • Arduino boards.

Device and design

A simple 12-volt BP without a transformer can be made of several radio elements. It is a diode bridge VD1-4 and 3 of the same type of transistor stabilizers included in series.


Another scheme consists of the following details:

  • 2 condensers C1 and C2;
  • 4 diodes forming the bridge VD1-4;
  • 1 Stabilion D1.

C1, connected to the 220 V network, quenches most of the voltage. It straightens the VD1-4 diode bridge. The chain D1, C2 is a parametric stabilizer, from the output of which a constant voltage is removed that feeds the load.


A more advanced device contains at the input resistance R1 to suppress the current and Rc chain - connected parallel to the C1 particulate container and the R2 resistor of a large nominal value for its discharge. The middle part of the scheme is the same. The output is installed an additional non-polar capacitor C3.


Further improvement involves the installation at the output of the VR1 stabilizer on the transistors or chip.


These blocks are dangerous, since their parts are under a voltage of 220. in the absence of a load (if the stabilizer is spoiled) the output potential will be equal to the network.

Principle of operation

The best transformer block on the transistors works as follows. 220 V is straightened by a condenser bridge and enters stabilizers. They are all fulfilled according to the same scheme, but are designed for different stresses. The first limits the potential of the network at the level of 150-180 V, the second stabilizer reduces it by about 2-3 times. The third gives the desired voltage. Changing Stabilitron D3, you can get a bipstranformator BP, for example, by 12 or 5 volts.

The block with RC chain is a voltage divider. In its top (according to the scheme), the shoulder has a C1 capacitor representing the reactive for AC (does not consume energy at all) resistance. In the lower part there is a diode bridge VD1-4 with a load (stabilitron, transistor, microcircuit, etc.).

The input voltage comes to the divider, straightens the bridge and enters the stabilizer that limits it to the required value.

Work schemes

All described devices are made on common radio elements. Below are the schemes with the designation of all parts.


In BP with transistor stabilizers KT940A, it can be replaced with high-voltage, withstanding more than 250 V, and KT815G - to another, with a minimum voltage of 80 V. When specified details, the device can give up to 300 mA. To increase the current strength, you need to install transistors on radiators. If instead of the KS512A stabilion to put D814D, then the output current of the device will decrease to 200 mA.


The traditional brass-informator unit on 12 V with RC chain gives only 20-40 mA. If after the bridge to install a powerful stabilitron D8155, which will limit the voltage to 16-19 V, and supplement the scheme by the stabilizer on the transistor, then the output current will increase to 120 mA. To increase it up to 180 mA, it is necessary to parallel condensers C1, C2 to solder another same.


The block is more stable on the 78L08 chip (Russian designation KR142B). With the details, it gives up to 200 mA.

Calculation of parameters

To prevent the breakdown of details of the best-to-informator schemes, they must be correctly calculated. For each device there is a method.

The transistor unit is considered according to the law of Ohm: u = i × r. It is necessary to calculate the resistance R1, R2, R3 on the basis of the value, voltage and current, which can withstand each stabilion.

R = U max / i min.

The calculation of the ballast capacitor for blocks with the RC chain is made according to the following formula C = I EF / 2 * 3,14 * F * √ (UP²-UV²), where:

  • C - Ballast Capacity (Farad);
  • UP and UR - feed and output voltage (volt);
  • I eff - current load;
  • F - signal frequency at the inlet of the device (hertz).

Since 1 pharaD = 1 million microfrades, then the formula can be simplified:

C = 3200 * i Eff / √ (UP²-UV²).


Resistance R1 (com) is approximately 0.025 from the size of the ballast capacitor. Its power should not be below 1 W (optimally 2-5 W).

If manual count is inconvenient, find and use the Calculator online.

Creating a power supply for 12V with your own hands

Bestrazing block can be made independently. First you need to select one of the shown schemes.

Support such tools and materials:

  • soldering iron, flux, solder;
  • radio components indicated in the figure;
  • wires in insulation for the formation of conclusions;
  • Foil Material (Textolite, Gheetinax) for the manufacture of printed circuit board;
  • drill with a thin (0.5-1 mm) drill;
  • nippers or scissors for clipping conclusions;
  • Pliers or tweezers.

To create the board, you will need an etching composition, for example:

  • chlorine iron solution;
  • A mixture of food salt (2 tbsp. l.), copper sipop (4 art. l.) and 0.5 liters of water.

Boards take place 2-6 hours. To reduce this period, the solution is recommended to heat up to + 50 ... + 60 ° C.

Next, follow these steps:

  1. Draw tracks on the board and etch them.
  2. Drill holes in the right places.
  3. Crop the legs of details and form them.
  4. Insert them into the holes and pecks.
  5. Install radiators (if necessary).

After assembling the board, the wires with the necessary connectors are connected to it. To turn on 220 V, a network plug is used, and at the output put any connector or a special plug.

Sooner or later, the question arises in front of the homemade - from which to feed the homemade, LED ribbon, etc. You can make the power supply yourself, you can buy a new, ready. There are several "folk" blocks, well-proven themselves. However, there is another option - the purchase of food supplies former in operation, but still possess good characteristics. This time I got a 12 volt block and as much as 5 amps.

The power supply should always have a power supply, even if the device consumes 2.3.4 amps. Completely block is suitable for powering the popular TS100 soldering iron or recently appeared SH72.

As always, to start the characteristics:

- Input Voltage: AC 100V-240V 50-60HZ - Output Voltage: DC 12V - Output Current: 5A - Output Power: 60 W - Operating Temperature: -30 - + 85 C - Size: 10.2 x 4.5 x 2 , 6 cm

Find out the actual price.

Already ordered used power supplies, they all turned out to be workers and always arrived in simple plastic bags. It did not exception and this sample.

The fact that the b / y unit say trimming input and output wires. However, dirt and dust is not at all, which means that the unit was previously operated in a closed case. Judging from the name of the lot, before the unit provided with a power monitor.

The massive components of the block are fixed by "sealant" and easily survived the road. A little went to one radiator. It is attached to the board with pins, which are soldered in the fee. Apparently, the road was pressed somewhere, the radiator leaned into the block and damaged the track section under the soldering. The problem is small and easily corrected.

The overall size of the board practically comply with the declared.

All the boards are used that I came across, were made from Ghetinaks and did not have fasteners under the screws in the case inserted on the guides and pressed the lid.

The block is neatly assembled, the flux traces are only in the places of the hand soldering of the wires. It is easy to see that high-voltage (hot) part of the scheme is separated from the "cold" part of the width of approximately one centimeter without any conductors. As a bonus, rubber seals remained on the underside of the board. Under the opamp, which we will see later, a slot is traditionally made in the board. This is not ventilation, it is a protection against the arc in the case of a breakdown of optocouplers. The label of Shima could not consider, lured with scratches.

The input filter has not one, but two chokes that plus. There is a varistor and a Condenser X2 type. In addition, in stock a fuse, which in my case turned out to be cut off on the one hand, but was easily restored. Under the heat shrinking on it there was an inscription 3.15 amp 250 volts.

All capacitors in the power supply circuit are installed from the well-known manufacturer JamiCon. The output filter is dialed from three capacitors (1000, 1000 and 470 μF. All 16 volts) and choke.

To consider the input capacitor, the transistor, dual diodes and the inter-winding capacitor had to be unscrewed and dropping radiators. The places of contact of the cases of the transistor and dual diodes turned out to be labeled thermal stuff. Under diodes not all over the spot, but there is.

The rectifier is built on the diode assembly of KBP206 by 600 volts and 2amper, quite sufficient in this case.

An interference Condenser X2 type with a capacity of 0.47 microf.

As a high-voltage field transistor FTA06N60D in an isolated case.

The inter-winding capacitor is applied, as it should be, Y1 type, which in the case of an abnormal situation do not closed, but are destroyed.

After removing the radiator, you can consider the labeling of the optocoupler and the slot in the board. A widespread PC817 applied here.

Dual Schottky Diodes MBR20100CT with a maximum current through one diode 10 amp.

To view the labeling of the smoothing capacitor of the rectifier, it was necessary to drive it from the sealant and draw. The declared capacity of 82 μF with nutrition from the 220 volt network is taken even with a decent reserve, based on the ratio of 1 μF per 1 W power.

So, as the unit used and worked in a close body, then the parameters of the capacitors could change. Therefore, it checked all electrolytic capacitors using a Multifunction TC-1 tester. As a result, no bad capacitor found - capacity, ESR and leakage were at a normal level.

82 μF 400 volts

Two output filter capacitor for 1000 ICF 16 volts showed almost the same results.

And the capacitance of the capacitor at 470 μF 16 volts was even higher than the stated.

Next to the transformer and one of the radiators are installed two more capacitors of 10 μF 35 volts, which were also good, despite the "warm" neighborhood.

At idle, the block behaves quietly, the output voltage consistently holds at 12.18 volts.

Tested block currents 1, 3 and 5 amps half an hour.

With a load current of 1 ampere, the outlet voltage decreased by only 0.07 volts, and the temperature of heating was only 38 degrees, which is rather "warm-up" mode for this unit.

With a current of 3 amps, the outlet voltage was exactly 12 volts. Radiator with spacing diodes was heated to 51 degrees, which is also absolutely not critical.

With a current of 5 ampers, the voltage sloping slightly, but rather the wires, probe and crocodiles, and it is impossible to call a critical drawdown. The current of the 5 amper block holds, heated only to 67 degrees.

Maximum, with my way of testing and switching, I managed to remove from block 5, 166 amps. Next, the block is in defense with the reduction of the voltage to zero, and its work is resumed after the load is removed. Similarly, the block behaves with a short closure at the output. And throughout the range of loads, the block behaves quietly, without pisch and tip on the radio.

And at the end, measured the level of ripples.

The generally accepted technique implies a soldering of additional capacitors with a capacity of 1000 μF and 0.1 μF (ceramics) directly to the output of the power supply and measurement of ripples on their outputs.

Measurements were carried out at idle and under load 1, 3 and 5 amps with a closed input of oscilloscope, 10 mV / division and 10 μs sweep. Pulsation at the exit even with 5 amps loads did not exceed 12 Milvololt.

Increased the scan to 10 milliseconds and received the results, as well as not different from the previous ones. Maximum 18 Millivolt !!!

Such low ripples were forced to doubt, but repeated tests of other results were not given.

Already from sports interest, additional capacitors dropped and re-conducted measurements at 10 mV / division and 10 μs sweep.

And in this case, at the maximum load, the pulsation did not exceed 30 Milvololt.

At 10 mV / division and 10 milliseconds of sweep, the results turned out to be almost the same, only the form of pulsations at the output characteristic of the pulse blocks was considered.

Before, it was already dealt with used power supplies from the Banggood store. Then these were blocks by 12 volts 2 amps and 12 volts 2.5 amps. We have been exploiting them for two years, and there are no complaints. They also differ in the stability of parameters and low ripples.

However, sometimes it is necessary to feed devices with a large consumption current and in this case the observed unit is more beneficial as two times more powerful.

A few words about the valuation. Blocks are available to lots one by one, three and five pieces. If you do not plan to feed several devices, you can buy one. But if there is a need and plans to use several blocks, it is more profitable to buy a lot of five blocks.

Power supply 12 volts 5 amp Lot 1 pc. - $ 5.92, taking into account delivery.

Power supply 12 volt 5 amp Lot 3 pcs. - $ 5.19 per one with delivery.

Power supply 12 volt 5 amp Lot 5 pcs. - 4.91 $ per one, taking into account delivery.

Summing up, you can talk about honestly declared characteristics of the lot. The unit confidently holds 5 amps with almost unchanged voltage at the output. There is a small supply for power, the presence of protection for the CW and overcurrent. The block works quietly and without the flooring on the radio. Well, and a big plus for low ripples, low heating temperature, aluminum radiators and the ability to waste time on building a power source for their projects.

Hello colleagues!

As promised, in this article we will make a power supply for 12V. IN last article we reduced the voltage on the transformer from 32V to 12V and now we will do from this transformer full 12V power supply constant voltage.

So, we need 4 diodes and condenser 470MKF 25B.


Diodes can be taken any, since the voltage will not be large. Condenser is needed at least 25V, because at the output with Power supply , DC voltage will be more 12V. . Do not be afraid of this - this is normal, since when the power supply is loaded, the power supply will give it 12V.

On diodes, however, as on the condenser, there is polarity. The conclusion on which the strip is drawn is a plus. Accordingly, the conclusion without strips is "minus".


We take two diodes and connect them as follows: "Plus" with a "minus". We take the remaining two diodes and just join them. You can unwind, but you can simply twist. I will twist:


I show you the simplest, you can say "handicraft", the way. Who needs it, can do it on a special board or in some case, who has what the need and fantasy. It also explains the principle of this action.

Next, we take these two "twists" and connect them between themselves so that the free "plus" on one "twist", connected with the same "plus" on another "twist". Also with "minuses": free "minus" on one "twist", we connect with the same one. We will get such a "square":


Then we attach the output with transformer To our diode bridge, which we turned out. One withdrawal from the transformer to the "plus minus" of a diode bridge and another withdrawal from the transformer to another contact "plus-minus" a diode bridge. Contacts "Plus-Plus" and "minus-minus" remain, while free.


After this "procedure", we take the capacitor. It also has polarity. Usually on the condenser, the contact "minus" is noted. Not marked contact, respectively, will be "plus".

Condenser We will attach to the diode bridge. We do this in such a scheme: "Plus" of the capacitor we join the contact "plus-plus" a diode bridge, and the "minus" of the capacitor we attach to the contact "minus-minus" a diode bridge.


Almost ready.

Now take two wiring of different colors. I will take a red for the "plus" and blue for "minus". Colors can choose anyone as comfortable or which has anyone. You can take one color and on one to tie a nodule.

Red wiring, which for the "plus", I solder a "plus plus" of a diode bridge. There is also the conclusion of the "plus" condenser.

Blue wiring, which for "minus", solder to the conclusion of a "minus-minus" of a diode bridge, where the condenser's "minus" conclusion is also located.


That's all!

Now I will measure the voltage:


Voltage is 16.3V DC. On "idle" it is normal, when the power supply will give the power supply to it 12V.

For cases where accurate voltage is needed, you can put an additional stabilizer. If this moment is interesting to someone, write in the comments and I will explain how!

Do not worry if something has not turned out the first time. Show persistence and patience, because you can learn something like that!

If you are interested in something like that, write in the comments. I will try to answer all questions and wishes!

Hello all radio amateurs, in this article I want to present you a power supply with voltage adjustment from 0 to 12 volts. It is very easy to put the desired tension, even in Milvololt. The scheme does not contain any purchased parts - all this can be pulled out from the old technology, both imported and Soviet.

Concept of BP (reduced)

The housing is made of wood, a 12 volt transformer is screwed in the middle, a condenser for 1000 μF x 25 volts and a board that adjusts the voltage.

How to make a power supply for 12V

Capacitor C2 must be taken with a large capacity, for example, to connect the amplifier to the power unit and that the voltage does not fail at low frequencies.

Wood case on homemade power supply

The VT2 transistor is better to install on a small radiator. Because with long work, it can warm up and burn, I have already burned 2 pieces until I put a decent radiator in size.

Homemade power supply 0 12 V

R1 resistor can be set permanent, it does not play a big role. From above on the case there is a variable resistor, which is adjusted voltage, and a red LED, which shows whether the voltage at the output of the BP.

Homemade power supply at 12 V

At the output of the device, to constantly not to screw the wiring to anything, I soldered crocodiles - it is very convenient with them. The scheme does not require any settings and works reliably and stable, it can really make any radio amateur. Thank you for your attention, good luck! Author:



Forum according to the schemes of the simplest BP

   Forum on the discussion of the material homemade power supply for 12V

Hello everyone's self-relocated. Many radio amateurs know that the power supply is expensive part of the whole electronics and often buy a good power supply is not possible, but each beginning to dealt with radio holder has an old computer unit, which has long been lying and not used. In this article, I will tell you how to make a laboratory power supply for various devices, such as an amplifier.

To begin with, it is necessary to decide what to be needed for the assembly, it is:

* Computer block itself, my power was 350 watts, which is enough for everything with a margin.

* Plywood, I had 4 segments.




* Screwdrivers.

* Soldering iron and soldering supplies.






, greens bigger.

* Nails, I preferred nails with a shallow hat.

* Rubber plugs mined from chemical tubes.

When everything you need is, you can proceed to the disassembly of the computer unit.

First, unscrew the upper bolts that hold the lid.

By revealing them, go to four bolts on the cooler.

After that, I will free your fee from the body, there are also bolts there, in my case, one black bolt was still hid in the middle, which I was at first and did not notice.

But, as it turned out, you don't pull out the fee, you need to disappear wires from the connection to the power supply of 220V. Be careful, nearby


May not be discharged and out of such high voltage current.

We also disappear wires from the switch.

Now the block board is easily removed, but

Native body is no longer useful.

Next that we will remove from the block there will be a bunch of wires, since we need only 3 of them, it is yellow (12 V +) and blue (-) and green for inclusion.

In order for the block to turn on the green wiring to be searched to the place of the accumulation of ferrous wires.

Now you will clean everything from dust, the cooler could not be cleaned, I disassembled it and as it should be missed by Solidol.

Everything is now clean and you can already move to the manufacture of the housing.

Armed with an electroll bitch drink down the bottom side, I made it 8 mm more on four sides than the fee itself.

In the middle, I made a bolt hole and gave it a bit to make a thread, with the help of it and four bolts around the edges will be attached to the fee.

We screw the board to the plywood on the central bolt.

After that, trying on another piece of plywood and measure the length we need and height. The height I made a little more cooler so that the power supply was not so bulky.

Before you sprinkle the front part, we note on it to our cooler, it will be right in the center.

We supply a pencil and drill two holes, the distance between them is made about 2 mm, then loosen the hole removing the partition to run the pylon of the electrol bike.

Sorser the seat of the cooler.

We try, it sits there well).

Four holes for bolts for fixing the cooler are made of small drill.

Now you can freeze the front part blank.

Front, so to speak the most important part of the block is ready, by analogy, cut the rear wall.

We try on the walls, it looks good, it's over the side lids.

Having simply at an even angle of the side wall, we plan a place to cut the corner.

The side wall is ready, you need another same. Just circle the previous one.

Under the cord 220 in the plug, the same thing that was in the native building, we need to be placed in the front of the block.

We cut down the same junk, ready.

Tighten the plug for two regular bolts.

Having done the deep holes in the front panel under the bolts Bratym Cooler.

Let's see how it all looks like, it seems good looks, of course I am not a designer).

You nail the lower and front side of our block into two nails with a shallow hat.

Since our block will turn on and off, then it is also necessary for the switch, I posted it next to the plug under the plug.

We do a place for the switch, the main thing is not to overdo it, then he will just hang out that it is not very good.

The highway sat down tightly and not the backup.

With the installed cooler, the front panel looks like this.

Since the rear panel should have a ventilation output, then using the jigsaw, we make an oval blowing.

To connect various devices to be used with these block, you need terminal workers, I found them from a school resistor.

From the reverse side, everything is dragged with the help of a nut and pressed with its help with a lifted contact.

It took two such terminal artes, one goes on a plus power, the other for minus.

And so the front panel looks like from the outside.

Having attached the rear panel, nail it to the rear with the already fixed front panel.

Since initially I did not think that the connections of the 220 V in the native body were short, so I had to replace them on the longest.

One wire I soldered to the plug, and the other through the switch.

The power supply was labeled that the blue wire is minus 12 volt line, and the yellow wire is plus the same line.

Plus I soldered higher, minus is located on the bottom.

Finish the board for four bolts.

The front panel is now equipped with electronics, so it remains only to the top and consolidate the sides.

By analogy with the bottom drinking and the upper cover. Fix it into four nails around the edges.

We smash two side covers, as well as 4 nails.

So that when connected is not mistaken with polarity, I made a screwdriver clarifying icons, plus and minus, now for sure without errors.

At the end, I added 4 legs made from traffic jams for chemical tubes, I saw them in half, because they were high and dragged on 4 screws one on each leg.

On this laboratory power supply is ready, you can listen to the car radio, check the light bulb on the performance of the light bulb.

All successful homemade and interesting ideas.

Become an author of the site, publish your own articles, descriptions of homemade with payment for text.

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12 volt constant voltage power supply consists of three main parts:

  • A lowering transformer from a conventional input voltage 220 V. At its output will be the same sinusoidal voltage, only reduced to about 16 volts at idle - without load.
  • Rectifier in the form of a diode bridge. It "cuts" the lower semi-sinusoids and puts them up, that is, it turns out the voltage, changing from 0 to the same 16 volts, but in the positive area.
  • The electrolytic capacitor of a large container, which smoothes semi-sinusoids of stress, making them approaching a straight line at 16 volts. This smoothing is better than the capacity of the capacitor.

The simplest thing is to obtain a constant voltage capable of feeding devices designed for 12 volts - light bulbs, LED tapes and other low-voltage equipment.

A lowering transformer can be taken from the old power supply of the computer or just buy in the store not to bother with windings and rewinding. However, to exit ultimately on the desired 12 volt voltage during running load, you need to take a transformer that reduces volts to 16.

For the bridge, you can take four rectifier diode 1N4001, designed for the voltage range we need or similar.

The capacitor should be a capacity of at least 480 microf. For good quality, the output voltage can also be more than 1,000 μF or higher, but it is not necessary to power the lighting devices. The range of operating stresses of the condenser is needed, say, volts up to 25.

Layout device

If we want to make a decent device that will not be ashamed to fit as a constant power supply, for example, for a chain of LEDs, you need to start with a transformer, installation fees for installing electronic components and boxes, where all this will be fixed and connected. When choosing a box, it is important to consider that the electrical circuits are warmed during operation. Therefore, the box is well found suitable in size and with ventilation holes. You can buy in the store or take the housing from the power supply of the computer. The last option may be bulky, but in it as simplification you can leave an existing transformer, even together with the cooling fan.

Power supply housing
Power supply housing
Power supply housing
Power supply housing

On the transformer we are interested in low-voltage winding. If it gives a decrease in voltage from 220 V to 16 V is the perfect case. If not, it will have to rewind it. After rewinding and checking the voltage at the output of the transformer, it can be fixed on the circuit board. And immediately think about how the mounting board will be attached inside the box. She has a landing hole for this.

Low-voltage winding
Low-voltage winding
Circuit board
Circuit board

Further installation actions will be held on this circuit board, it means that it should be sufficient on the area, length and allow the possible installation of radiators to diodes, transistors, or chip, which should still be placed in the selected box.

Diode bridge
Diode bridge

The diode bridge is collected on the circuit board, such a rhombission from four diodes should be obtained. Moreover, the left and right pair consist equally from diodes connected in series, and both pairs are parallel to each other. One end of each diode is marked with a strip - this is indicated plus. First we solder diodes in pairs to each other. Consistently - this means plus the first is connected with a minus second. Free ends of the pair will also work out - plus and minus. In parallel to connect the couples - it means to solder both plus pairs and both minuses. Now we have a weekend contacts of the bridge - plus and minus. Or they can be called poles - upper and lower.

Scheme of a diode bridge
Scheme of a diode bridge

The remaining two poles are left and right - used as input contacts, they are supplied to an alternating voltage from the secondary winding of the lowering transformer. And at the outputs of the axle, the diodes will fill a pulsating alpoporant voltage.

If you now connect in parallel with the output of the condenser's bridge, observing the polarity - to the bridge plus - plus a capacitor, it will start smoothing, and as well as it has a container. 1,000 ICF will be enough, and even put 470 μF.

Attention! Electrolytic condenser - unsafe device. With an incorrect connection, when the voltage is applied outside the operating range or with a large overheating, it can explode. At the same time, all its internal contents are scattered around the district - the rags of the housing, metal foil and electrolyte splashes. What is very dangerous.

Well, here it turned out the easiest (if not to say, primitive) power supply for devices with voltage 12 V DC, that is, DC.

Problems of a simple power supply with load

Resistance drawn in the diagram is the equivalent of the load. The load should be as follows that the current, its feeding, when the voltage is supplied at 12 V, did not exceed 1 A., you can calculate the load capacity and resistance by formulas.

Load and Resistance Power Formulas

From where the resistance r = 12 ohms, and the power p = 12 watts. This means that if the power is more than 12 watts, and resistance is less than 12 ohms, then our scheme will start working with overload, it will be very warm and quickly burns. You can solve the problem in several ways:

  1. Stabilize the output voltage so that with the current load resistance, the current did not exceed the maximum allowed value or with sudden current jumps on the load network - for example, at the moment of inclusion of certain devices - the peak values ​​of the current are cut to the nominal. Such phenomena are when the power supply is powered by radio electronic devices - radio receivers, etc.
  2. Use special protection schemes that would disconnect the power supply when the current is exceeded on the load.
  3. Use more powerful power supplies or power supplies with a large power reserve.

Power supply with stabilizer on the chip

Figure below shows the development of the previous simple scheme with the inclusion of a 12-volt stabilizer LM7812 chip.

Power supply with stabilizer on the chip
Power supply with stabilizer on the chip

It is already better, but the maximum current in the load of such a block of stabilized nutrition still should not exceed 1 A.

Increased power supply

A more powerful power supply can be done by adding several powerful cascades into the Darlington type TIP2955 in the diagram. One stage will give an increase in the load current in 5 A, six composite transistors connected in parallel will provide load current in 30 A.

TIP2955 darlington transistors
TIP2955 darlington transistors

A diagram having such an output power requires appropriate cooling. Transistors must be provided with radiators. The additional cooling fan will be needed. In addition, you can protect yourself with fuses (not shown in the diagram).

The figure shows the connection of one composite transistor of the Darlington, which makes it possible to increase the output current to 5 amps. You can increase further by connecting new cascades in parallel with the specified one.

Connecting one composite transistor of Darlington
Connecting one composite transistor of Darlington

Attention! One of the main disasters in electrical circuits is a sudden short circuit in the load. At the same time, as a rule, there is a current of gigantic force, which burns everything in its path. In this case, it is difficult to come up with such a powerful power supply that is able to withstand it. Then apply protection schemes, ranging from fuses and ending with complex schemes with automatic shutdown on integrated circuits.

Good day dear friends, in this article I want to share with you your experience in creating pulsed power sources. It will be about how to assemble with your own hands the pulse power supply on the IR2153 microcircuit.

The IR2153 microcircuit is a high-voltage shutter driver, there are many different schemes, power supplies, chargers, etc. The supply voltage varies from 10 to 20 volts, the operating current is 5 mA and the operating temperature is up to 125 degrees Celsius.

Beginner radio amateurs are afraid to collect their first pulse power supply, very often resort to transformer blocks. I was also afraid of afraid, but still gathered and decided to try, especially since the details were enough for its assembly. Now let's talk not much about the scheme. This is a standard half-lit power supply with IR2153 on board.

Powerful pulse power supply by 12 volts with your own hands


Diode Bridge at the inlet 1N4007 or the finished diode assembly designed for current at least 1 A and reverse voltage of 1000 V.

Resistor R1 at least two watts can also be 5 watts 24 com, resistor R2 R3 R4 with a power of 0.25 watts.

Condenser electrolytic on high side 400 volts 47 μF.

Output 35 volts 470 - 1000 μF. Filter Capacitors Calculated for voltage at least 250 V 0.1 - 0.33 μF. Capacitor C5 - 1 NF. Ceramic, C6 Condenser Ceramic 220 NF, C7 Film 220 NF 400 V. Transistor VT1 VT2 N IRF840, Transformer From the Old Computer Power Block, The diode bridge at the outlet is full of four ultra-free HER308 diodes or other similar.

The archive can download the scheme and fee: Powerful pulse power supply by 12 volts with your own hands

The printed circuit board is made on a piece of foil one-sided glass fiberstolite by the LUT method. For convenience of connecting power and connect the output voltage on the board there are screw terminals.

Powerful pulse power supply by 12 volts with your own handsPowerful pulse power supply for 12 in your own hands

Pulse power supply diagram 12 V

The advantage of this scheme is that this scheme is very popular in its kind and it is repeated by many radio amateurs as their first impulse power supply and efficiency, and once again, no longer speaking. The diagram is powered by a 220 volt network voltage in the input is a filter that consists of a throttle and two film capacitors calculated for a voltage of at least 250 - 300 volts with a capacity of 0.1 to 0.33 μF them can be taken from a computer power supply unit.

Powerful pulse power supply for 12 in your own hands

In my case there is no filter, but it is desirable to put. Next, the voltage enters the diode bridge calculated on the reverse voltage of at least 400 volts and a current of at least 1 amp. You can also put a ready-made diode assembly. The further scheme is a smoothing capacitor with an operating voltage of 400 V, since the amplitude value of the network voltage is in the area of ​​300 V. The capacity of this capacitor is selected as follows, 1 μF per 1 watt of power, since I'm not going to dig up a large current from this block, In my case, there is a condenser at 47 μF, although it is possible to pump up one hundred watts from such a scheme. The meal of the chip is taken from the change, the power supply is organized here. The resistor R1, which ensures that the current is desirable, it is desirable to put more than two watts that is heated as it is carried out, then the voltage is rectified with only one diode and enters the smoothing capacitor and then on the microcircuit. 1 Chip output plus power and 4 output is minus power.

Powerful pulse power supply for 12 in your own hands

You can collect a separate power source for it and apply according to the polarity of 15 V. In our case, the microcircuit operates at a frequency of 47 - 48 kHz for such a frequency of the RC chain consisting of a resistor R2 15 com and film or ceramic capacitor per 1 nf. With this scenario, the details of the microcircuit will work correctly and produce rectangular pulses on their outputs that enter the shutters of powerful field keys through the R3 R4 resistors. Renses of them may deviate from 10 to 40 ohms. Transistors It is necessary to install N channels, in my case cost IRF840 with an operating voltage of the flow of the source 500 V and the maximum flow current at a temperature of 25 degrees 8 A and the maximum dispersible power of 125 watts. Further, the scheme is a pulse transformer, after it is a full-fledged rectifier of four Her308 brand diodes, ordinary diodes do not fit here as they will not be able to work at high frequencies, so we set ultra-free diodes and after the bridge the voltage already enters the output capacitor 35 volts 1000 Igf , It is possible and 470 μF of particularly large tanks in pulse power blocks is not required.

Powerful pulse power supply by 12 volts with your own hands

Let's go back to the transformer, it can be found on the boards of computer power supplies, it is not difficult to determine here it is not difficult in the photo the biggest here it is necessary for us. To rewind such a transformer, it is necessary to glue the glue to which the halves of ferrite are glued, for this we take a soldering iron or soldering hair dryer and slowly warm up the transformer, you can lower in boiling water for several minutes and gently disconnect the half of the core. We chat all the basic windings, we will wink your own. At the calculation of the fact that I need to get a voltage in the region of 12-14 volts, the primary transformer winding contains 47 turns with a wire of 0.6 mm in two veins, we make isolation between the winding of the usual scotch, the secondary winding contains 4 turns of the same wire in 7 live . It is important to carry out the winding in one direction, each layer isolate with a scotch, noting the beginning and the end of the windings otherwise it will not work, and if there is a block then the unit will not be able to give all the power.

Block checking

Well, now let's test our power supply as my option is fully working, I immediately connect to the network without a safety lamp.

We will check the output voltage as we see in the area 12 - 13 in not much walking from the voltage drops on the network.

Powerful pulse power supply by 12 volts with your own hands

As a load, the automotive lamp at 12 in a power of 50 watt current flows 4 A. If such a unit is supplemented with a current and voltage adjustment, put the input electrolyte of a larger capacity, then you can safely collect a charger for a car and a laboratory power supply unit.

Powerful pulse power supply by 12 volts with your own hands

Before starting the power supply, you must check the entire installation and turn on the network via an insurance lamp of incandescent 100 watts, if the lamp is full of intensity means looking for errors when installing the nozzles not washed flux or no one component and T d. With the correct assembly, the lamp should be slightly To flare and go out, it says to us that the condenser at the entrance has been charged and there is no mistakes in the montage. Therefore, before installing the components on the board, they must be checked even if they are new. Another not a little important moment after starting the voltage on the chip between 1 and 4 with the output must be at least 15 V. If this is not so selecting the rating of the resistor R2.

Powerful pulse power supply by 12 volts with your own hands

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Types of power supplies, their main technical characteristics

The power supply is a secondary energy source for technical devices that converts the power supply voltage into their operating voltage.

The most popular power supplies in which the primary voltage is an alternating voltage of the household electrical network, equal to 220 volts, and the secondary - converted to constant, equal to 24/12 / 5/3,3 V. According to the principle of voltage conversion, power supplies (BP) are divided into two types:

  • Transformer - when the transformation is carried out by means of a lowering transformer, they are called linear;
  • Pulse - The transformation is carried out due to the presence of electronic components providing voltage conversion, they are called inverter.

If the output voltage stabilizer is provided in the BP scheme, then such a device is called a stable power supply.

The main technical characteristics that determine the possibility of using such technical devices are:

  • electrical power measured in watts (W or in × a);
  • inlet and outlet voltage measured in volts (B);
  • output current measured in amperes (A);
  • efficiency - parameter useful when using high power BP, is measured in%;
  • The presence of elements for the protection of internal electrical circuits from overloads and short circuit currents.

Application area

Power supplies with second-voltage 12 volts of pulse type are used to connect to the household electrical network:

  • personal computers of various types - to charge their batteries and work directly from the network;
  • To charge electronic gadgets , including cell phones and smartphones, players and camcorders, as well as other devices that have battery batteries in their design;
  • To charge a manual portable electrical tool - screwdriver, Bulgarian, etc.;
  • To connect LED lighting devices (LED lamps and ribbons);
  • To use other devices Supporting work from a direct current network with a voltage of 12 V and up to 5 amps, - car radio or auto receivers in a house or garage.

Schematic diagram and principle of work

The schematic diagram and the principle of operation depends on the type of device, and therefore it is necessary to consider them separately:

The analog type of BP has a lowering transformer in its scheme, which provides the value of the secondary voltage in the specified values, and the diode bridge, which serves to straighten it. The simplest scheme of such a device is as follows:

Analog Power Supply Scheme

Concept of analog power supply

The capacitors installed in the diagram provide the smoothing of the voltage pulses at the output of the power supply.

Transformer power supply

The inverter type of BP works at the expense of the electronic components included in the diagram of the device. The supply voltage is supplied to the input diode bridge, and its peaks are smoothed by installed capacitors. After that, the signal is converted to other elements of the circuit (transistors, chip, thyristors, etc.) and is supplied to the pulse transformer.

Transformers of this species are made on the basis of ferromagnetary materials, therefore have small overall dimensions that allow minimize the size of the BP. The voltage obtained after the transformation is supplied to the load (power supplies). This type of BP is called a scheme with galvanic junction.

Pulse power supply circuit

Pulse power supply on an integrated circuit and with designer resistors

There are BP schemes without using a galvanic compound. In this case, the input signal is immediately fed to the low-pass filter.

Impulse power block

Calculation of power supply power by 12 V

Power BP is one of the main technical characteristics that determine the possibility of connecting to it of one or another load. Power therefore can be calculated in different ways:

For LED tapes.

In this case, the calculation is performed as follows:

  • The basis of 1 meter LED-ribbon is taken as the basis, indicated by the manufacturer on the package;
  • its length is determined;
  • These values ​​are variable, and the resulting expression increases by 30%.

An increase of 30% provides the necessary power supply. This calculation can be expressed by the following formula:

PBlok. = P. UD × L. Ribbons × K. Stock Where:

PBlok. - electrical power supply power;

PUD  - electrical power of 1 meter of LED tape;

LRibbons - Length of the tape;

KStock - Power reserve factor.

For a personal computer.

If it is necessary to determine the power of the BP personal computer, you should know the power of all the elements of the devices included in its kit. This is a difficult task, so there are special programs and online calculators that serve to perform such a calculation. Here is some of them:

  • OuterVision® - Calculator, download link:
  • Company "ENERMAX" , Power Calculator - Link for download:
  • MSI - Power Supply Calculator, Link to download:
  • KSA POWER SUPPLY CALCULATOR Workstation - Link to download:

To charge electrical tools and electronic gadgets.

When it is necessary to determine the power of the BP to charge the screwdriver, a smartphone or other electronic device, you need to know their electrical power and take into account the reserve factor. This can be reflected by the following formula:

PBlok. = P. Devices × K. Stock

Diodes for power supply

To straighten the alternating voltage of the household electrical network in the diagrams of power supplies and other electronic devices, diodes collected on a bridge circuit. A schematic semiconductor diode looks like this.

Scheme of a semiconductor diode device

Device of semiconductor diode.

For the diode bridge device, 4 of the same type of diodes are used, which are connected in a certain way shown in the following scheme. Their technical characteristics must correspond to the value of current flowing through them, as well as the magnitude of the allowable reverse voltage.

The diagram of the connection of diodes on the pavement scheme

The diagram of the connection of diodes on the pavement scheme

Stabilization of tension

To stabilize voltage in BP, electrolytic capacitors of large capacitance and stabilion are used. Capacitors smooth voltage signals that have a semi-sinusoidal form almost to a straight line. The greater the capacitor capacity, the signal at the output of the more correct shape and tends to the straight line. Stabilians ensure the constancy of the voltage at the output of the power supply.

Pulse power supply 12 V do it yourself - scheme

There are a large number of different power units that have different specifications and collected on various electronic components. Below is a diagram of a pulsed BP with a secondary voltage of 12 volts.

Circuit diagram of the pulse power supply unit

Circuit diagram of the pulse power supply unit

With independent manufacture of such devices, it is necessary to remember that in order to ensure a predetermined voltage pulsation at the output, capacitors must be taken from the calculation of 1 μF per 1 W output power. Electrolytic capacitors must be calculated on the voltage of at least 350 V. The optimal ratio of power of BP and the technical characteristics of the electronic components is given in the following table:

Power Supply Elements of the scheme
power, kWt Talk, A. Diode current, and Capacitor Capacity, ICF
0.1. 0.4. 0,2 one hundred
0,2 0.8. 0.4. 200.
0,3. 1,2 0,6 300.
0.5. 2 1 500.
1 4 2 1 000
2 8 4 2 000
3 12 6 3 000
5 20 ten 5 000

The main stages of the manufacture of the pulse power supply 12 in their own hands

Work on the manufacture of BP can be divided into several stages: preparatory, installation and inspection of performance. In this article, consider the manufacture of the power supply according to the scheme shown in Figure 10.

Preparatory stage

During this period, power is calculated. It must be sufficient to use it with the load planned to connect. The form and scheme of BP is selected (see Figure No. 10), after which the necessary components are purchased. In this case, this is:

  • PTC thermistor;
  • two capacitors from the calculation of 1 μF per 1 W power;
  • Diode bridge (diodes must match voltage and current);
  • Drivers - IR2152 (IR2153, IR2153D);
  • Field transistors - IRF740, IRF840;
  • transformer (can be used by PC);
  • Diodes installed at the exit, HER series.

Installation of the power supply

Step-by-step instructions for the manufacture of impulse BP on the above scheme looks like this:

Checking performance

When the BP is assembled, you need to check it, for this:

  • The load is connected to the output of the power supply;
  • BP is included in the electrical network.

If the connected load works normally: LED lamps emit light, gadgets and tools are charged, and other techniques work - it means that the installation is completed successfully. Another way to manufacture the power supply is the placement of all the elements of the device on the Dean Rake.

Dean Rake is a metal profiled band, intended for attaching electrical devices and elements of electrical circuits.

When using a Dean Rake, the need for the installation of the circuit board disappears, however, the design is obtained more voluminous, because The connection between the elements of the scheme has to be performed using connecting wires.

Nuances manufacturer of power supply for screwdriver

When making a power supply unit 12 in your own hands to connect a screwdriver to an electrical network, it is necessary to take into account the following nuances associated with its use:

  1. The output voltage must be 18-19 V, otherwise the power of the device will significantly decrease.
  2. Electronic components of the BP scheme must correspond to the nominal current of the operating screw.
  3. The size of the collected block should be so in order to accommodate the dismantled battery (in the case of the manufacture of built-in design).

The rest of the manufacturer's stages are similar, as in the case of a separately placed version of the BP.

Where to buy and how much is the power supply 12 V

They are sold in consumer electronics stores, office equipment, as well as in organizations specializing in their repair. In addition, on the Internet there are also offers of various companies offering for the implementation of BP of various orientation.

DC-12V, 20.8A power supply unit, 250 W in a waterproof case, protection degree - IP67

The cost of BP depends on their technical characteristics and type of execution that determine the possibility of using this device. The higher the power and degree of protection - the greater the price. It can be from several hundred to several thousand rubles. Cheapest models:

  • ArDV-05-12A (12V, 0,4A, 5W) - 200 rubles;
  • ARDV-12-12AW (12V, 1A, 12W) - 300 rubles;
  • ArDV-24-12A (12V, 2A, 24W) - 400 rubles.

Models in the next segment:

  • APS-100L-12BM (12V, 8.3A, 100W) - 800 rubles;
  • APS-150-12BM (12V, 12.5A, 150W) - 1 000 rubles;
  • APS-250-12BM (12V, 20.8A, 250W) - 1,400 rubles.

The presence of a large number of proposals on the market of auxiliary devices for household appliances and appliances allows you to select the power supply in accordance with the requirements for it. And the presence in free access of various schemes, as well as electronic components, allows you to make a BP with your own hands even a novice electronics lover having initial skills to work with a soldering iron.

Video: Power supply for a screwdriver on 12V from computer BP.

This type of power sources is also called laboratory, and not in vain! It is suitable not only for powering various devices, but also as a universal charger for absolutely any batteries.

As it seems to me, the mega power supply is simple and perfectly suitable for a novice radio amateur. The power supply can be built on various voltage and current ranges, it all depends on specific tasks. Today we will look at the power supply to the most popular range of 0-30 volts / 0-10 Amer. The choice of such a range is also due to the use of a Chinese voltammermeter with a current range up to 10a.

The conditionally power supply can be divided into 3 parts:

 1 Internal power source.

It is any compact source voltage 12 volts and a current of at least 300 mA. It is applied to power the PWM controller, the cooling fan and a voltammermeter. You can use absolutely any 12 volt adapter. To tell how to collect such in this article I will not, we will use a ready-made AC-DC converter from China here:

 2 Management module.

It is a micrower TL494 with a small driver on 4 transistors:

Thanks to the use of built-in operating amplifiers, the TL494, the TL494 is obtained very simple, such an inclusion is widespread in radio amateurs. Previshor R4 set the desired maximum voltage, R2-current Rule collect on a separate scarf:

3 power part. The main part of the components can be used from an old computer unit, the main thing that it is the corresponding topology.

Input filter, rectifier, capacitors from a computer power supply.

A novice radio amateur can scare the power key control transformer, it will have to be made independently. But do not hurry with the conclusions, I assure you to make it very simple.

It will take a ferrite ring R16 * 10 * 4.5 and three segments of 1 meter of MGTF wire 0.07kv.m. Just wrap on the ring 30 turns in 3 wires.

Throttle L1 winds on a ferrite ring from the same computer BP, pre-wet all the windings from it and wind the copper wire with a long 1.5-2m cross section 2mm, this will allow you to make the specified parameters (this is for those who have nothing to simulate inductance).

Also in most normal computer BP there is a second choke on a ferrite rod, it can be left as it as L2 in most cases.

The power transformer can also be used as it is, but then the output voltage will be about 20 volts. For 30 volts, the secondary winding will have to be reworked.

When I need to remove big currents I prefer to use ferrite rings.

Calculation for our power supply unit 30 volts 10 amp.Transformer donor from computer BP 39/20/12:

All major components are placed on PP standard sizes under the computer power supply housing:

By the way, after assembling the control board and the winding of the GDT transformer, they can be checked even if you do not have an oscilloscope.

In the absence of errors during installation and serviceable components, the scheme practically does not need to be configured.

To control the fan, I usually use a temperature control circuit on LM317

or KCD 9700 thermostats. And the other is immediately.

The front panel is drawn in FrontDesigner 3.0 and is printed on a self-adhesive photo paper, then a self-adhesive film is selected for textbooks and books (there is in any office magage).

Here is the case of the future BP almost ready:

I will add another version of the control module easier and more powerful, but slightly more expensive

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