In this article you can find detailed step-by-step instructions for making a 220 V 50 Hz AC inverter from a 12 V car battery. Such a device is capable of delivering power from 150 to 300 W.
The circuit diagram of this device is quite simple..
This circuit operates on the principle of Push-Pull converters. The heart of the device will be the CD-4047 board, which operates as a master oscillator and also controls field-effect transistors that operate in switch mode. Just one transistor can be open; if two transistors are open at the same time, a short circuit will occur, as a result of which the transistors will burn out; this can also happen in case of improper control.
The CD-4047 board is not designed for high-precision control of field-effect transistors, but it copes with this task perfectly. Also, for the device to operate, you will need a transformer from an old 250 or 300 W UPS with a primary winding and a middle positive connection point from the power source.
The transformer has a fairly large number of secondary windings; you will need to use a volt-ohmmeter to measure all the taps and find a 220V network winding. The wires we need will give the highest electrical resistance of approximately 17 ohms, you can remove the extra leads.
Before you start soldering, it is advisable to double-check everything again. It is recommended to select transistors from the same batch and the same characteristics; the capacitor of the driving circuit often has a small leakage and a narrow tolerance. Such characteristics are determined by a transistor tester.
Since the CD-4047 board has no analogues, you need to purchase it, but if necessary, you can replace the field-effect transistors with n-channel ones with a voltage of 60V or more and a current of at least 35A. Suitable from the IRFZ series.
The circuit can also operate using bipolar transistors at the output, but it should be noted that the power of the device will be much less when compared with a circuit that uses “field switches”.
Limiting gate resistors should have a resistance of 10-100 ohms, but it is preferable to use 22-47 ohm resistors with a power of 250 mW.
Often the master circuit is assembled exclusively from the elements indicated in the diagram, which has precise settings at 50 Hz.
If you assemble the device correctly, it will work from the first seconds, but when starting it for the first time, it is important to be on the safe side. To do this, instead of a fuse (see diagram), you need to install a resistor with a nominal value of 5-10 Ohms or a 12V light bulb, in order to avoid the transistors exploding if mistakes were made.
If the device operates stably, the transformer will make a sound, but the keys will not heat up. If everything works correctly, the resistor (bulb) needs to be removed, and power is supplied through the fuse.
On average, the inverter consumes energy when the robot is idling from 150 to 300 mA, depending on the power source and the type of transformer.
Then you need to measure the output voltage, the output should be about 210-260V, this is considered a normal indicator, since the inverter does not have stabilization. Next, you need to check the device by connecting a 60-watt light bulb under load and letting it run for 10-15 seconds; during this time the keys will heat up a little, since they do not have heat sinks. The keys should heat up evenly; if the heating is not uniform, you need to look for where errors were made.
We equip the inverter with the Remote Control function
The main positive wire should be connected to the middle point of the transformer, but for the device to start working, a low-current positive must be connected to the board. This will start the pulse generator.
A couple of suggestions about installation. Everything is installed in the computer power supply case; the transistors should be installed on separate radiators.
If a common heat sink is installed, be sure to isolate the transistor housing from the heatsink. The cooler is connected to a 12V bus.
One of the significant disadvantages of this inverter is the lack of short circuit protection and if it occurs, all transistors will burn out. In order to prevent this, you must install a 1A fuse at the output.
To start the inverter, a low-power button is used, through which plus will be supplied to the board. The power busbars of the transformer should be fixed directly to the radiators of the transistors.
If you connect an energy meter to the output of the converter, you will be able to see that the outgoing frequency and voltage are within the permissible limits. If you get a value greater or less than 50Hz, you need to adjust it using a multi-turn variable resistor, it is installed on the board.
Comments (40):
#1 Snow White February 19 2015
Perfetto. Excellent This circuit seems to be what I was looking for about the transistor, very interesting. If you increase the number of turns, say three times, the current on KT 817 will also drop to 0.6. It doesn't work fast enough, is this the reason for the high current?
To be honest, I haven’t tried to increase the turns. As for the performance speed, yes, that’s why it was replaced with KT940. the current can be reduced further. From the lamp, take only the lamp itself and throw the board out of it. then the current is in the range of 0.3-0.35A..
#3 Selyuk May 12 2015
Everything is very “simple”, but where can I get the transformer cups??
#4 root May 12 2015
In the transformer design of this high-voltage converter there is no gap between the ferrite cups, so you can try using a ferrite ring or frame from a pulse transformer with a ferrite core (you can take it from a non-working computer power supply).
You will need to experiment with the number of turns and output voltage.
#5 pavel June 01 2015
What is the principle for calculating a transformer and selecting transistors for this inverter? I would like to make one with a power supply of 60 volts.
The cups were taken because they were just there, and the number of turns in such a core is needed less. I haven’t tried ferrite rings; it works fine on regular W-shaped ferrite. I don’t remember how many turns I wound, the primary one seemed to be 12 turns with 0.5mm wire, and the booster one was done by eye until the frame on the core was filled. The transformer was taken from a 4 by 5 cm monitor.
#7 Egor October 05 2015
I have a question for you: how many ohms is the resistor on the left at 220???
I'm just not very good at electronics)))
#8 root October 05 2015
If there are only numbers next to the resistor, that means the resistance is in Ohms. In the diagram, the resistor has a resistance of 220 ohms.
Tell me, is it possible to use your circuit to power the MTX-90 thyratron and not from 12, but from a 3.7 volt battery?
If possible, what are the best transistors to use? The MTX-90 has a small operating current - from 2 to 7 mA, and the voltage for ignition needs about 170 volts, well, you can experiment with this with a transformer (about voltage).
I don’t even know what to answer. Somehow I didn’t think about it.. Why do you need to power the thyratron from this circuit? In principle, it will work, of course, the only question is how... from 3.7 volts it is also possible, but the windings must be recalculated or selected experimentally.
#11 Oleg December 13 2015
People, tell us how to make an inverter from transistors from a Chinese typewriter on a control panel. Is it possible to install a ring ferrite core and is it possible to make a 3-fold difference in turns? I should make an inverter this way just for fun and to make it easier. And is it possible to set the input voltage to somewhere around 3V?
Answer please! I will be glad if you answer all my questions! I'm waiting for your answers!
#12 Alexander December 17 2015
I have 30/10 ferrite cups, is it possible to wind a trans on them and what number of turns should be wound, at least approximately.
#13 Alexander January 24 2016
Everything works great there, both the 15 watt lamp and the 20 watt one. More powerful transistors are simply needed. KT940 can be left alone, but 814 could at least be replaced with KT837. And if the current is high, you don’t need to rewind anything, you just need to increase the value of the resistor to 3.1k. And the transformer is not necessarily of this size, even a pulse generator will work from charging, transistors will still play a special role. p.s. These transistors have a power of no more than 10 watts
#14 Eduard February 01 2016
What kind of transistor can I replace KT814 with? Can I use 13005 or KT805?
#15 Alexander February 03 2016
Change it to KT805 - you'll scrape off a lot of power, because according to the datasheet, KT805 can give up to 60 watts
KT814 is p-n-p conductivity, and KT805 and 13005 are n-p-n..., of course you can’t Eduard...
#17 Mars May 11 2016
Instead of KT814 I installed KT816.15W lamp pulled.
#18 sasha November 06 2016
I installed KT805 and KT837. primary 16v.0.5mm. secondary 230v. 0.3mm. lamp 23W. glows great.
#19 Eduard November 19 2016
March. counter question, what then can replace the KT940, so that the KT814 can be replaced with KT805 or 13005 and change the power polarity? An idea arose: I removed the 12-volt pulse transformer from the electronic transformer for halogen lamps, there is just a secondary of 12-14 turns and The primary is about 150-200 turns. If you deploy it as a booster and plug it into this circuit? I think it should work, but if you replace the combination of KT814 and KT940 with something more modern, then you can squeeze out up to 40 W of power? I also want to try it on the UC3845 PWM controller , the circuit there is generally primitive: a UC3845 microcircuit, in its circuit a frequency-setting resistor and a film capacitor, an IRFZ44 field-effect transistor and a transformer from an electronic transformer included in the circuit as a step-up, as a result we have up to 100 W of power at 12 volts
and why "..940 outputs in the old colors in abundance.. everyone has nowhere to put it... replace it with any reverse transistor, but you want 805, then yes..940 on forward conduction.... and change the polarity... but again -why do we all have so many of these transits in our bins...
#21 pavel February 09 2017
why do you need to increase the power of the circuit :)? What, will you use KrAZ batteries (190 a/h)?? this circuit makes sense, as a friend correctly said, if you use a bulb from a lamp with a burnt-out circuit. Otherwise, to hell with the button accordion: an LED lamp from the same battery, with the same light output, will illuminate many times longer!..
#22 pavel February 09 2017
Now about the transistors: you can change them, but you need to remember that any power transistor provides its declared power only when using an appropriate heat sink. this fact directly affects the dimensions of the entire device. and where will you get energy saving? l ampu more powerful than 30 watts = 150? I haven't seen it on sale. and I already talked about the battery for such a “pacifier” :). so, know your limits, inventors, good luck!
#23 Eduard February 24 2017
March, I just have a problem with the Soviet KT940 and KT814. Basically in my reserves I have imported powerful high-frequency bipolar transistors 13005 for 5 amperes 400 volts, and the like. They managed to light the flask at full brightness from a 30 W energy-saving device, while the transistor was slightly warm. And the Soviet KT814 and KT805 ARE GLUGGY BY THEMSELVES BOIL QUICKLY EVEN WITH A RADIATOR
I would not say that the KT805 is buggy... depending on which one you use. in plastic they are unreliable, there is such a thing, and then for some 80 years. take the 805 in metal, it’s generally an indestructible transistor. However, it is necessary to emphasize the fact that they are buggy not because they are bad, but because they were not entirely in capable hands, just
But you can even install imported microwave transistors, it will work!!! verified!!. In this article, I wasn’t trying to create a miniature lamp, but rather how to fix a burnt-out lamp at minimal cost. to serve again
the 814 collector should be grounded through a 10 µF capacitor, otherwise when switching the surge is very large.
The 814 transistor is in a half-open state - however, it needs a radiator.
It was easier to use a blocking generator.
what other 10 microfarad capacitor, what nonsense, is it really not clear from the photo that the miniature radiator will all fit into a pack of cigarettes. and using a blocking generator is no easier. there you need at least three windings. and the transistor will heat up there no less!!!
#28 IamJiva August 14 2017
blocking generator serves the same purpose, to provide feedback (bring the microphone to the speaker so that it buzzes), if you did without a microphone, why don’t you need it, here you got by adding a transistor, in blocking you can get by with one transistor, and turn the phase around with turns of the winding, which (allow ) can be independently connected in any polarity. You can squeeze out a lot of watts, but it’s difficult, part of the energy (for powerful lamps is significant, up to 90%) is lost on the diode bridge and electrolyte (in the lamp rectifier) that are cheap (especially if powerful) and 50Hz are suitable, at 50kHz smoke can already come from them and the voltage never appears to start the lamp, 50Hz diodes (simple, that is, not ultrafast or Schottky) do not have time to lock, and drain the charge back into the winding or somewhere else, this causes heating of everything and incorrect operation of the generator, the electrolyte has inductance (series) , and a short pulse it only “recognizes” but is in no hurry to carry out the order, while waiting for the command to set it aside... the current begins to increase to infinity or as much as they give, for 50Hz instantly, for 50kHz - never... the transistor needs to be fast, it can heat up and NO way, IRF840 2pcs, correctly used, provided on 4 4ohm columns of 500wt each, 2000Wt of power in class D, powered by +-85V (170V) TL494 PWM, Ir2112 driver in the gates, 4pcs ultrafast diodes shunt the SI and IC, varistors 400V BC 30V SI
2kW drum and bass power, they were a little warm on the same radiators as here, at the output there is a choke from the fuel assembly and 200 turns, at 2500wt they burned out without warning
It would be a good idea to bypass the output transformer of the primary with a diode, or better yet with a varistor (from flyback impulses possible in the event of a load disconnection, the selection of transistors and turns of the primary for maximum efficiency is as important and valuable as the ratio of sugar and vinegar with water + time on the timer in the microwave, so go away and take out the lollipops, the circuit works like a juggler you’ve never seen, they hope for the ease of transferring the ideal-harmony-efficiency-power to another circus and there’s no need for a jacket
One question for the author. This converter will pull an electric razor from Kharkov, Agidel, Berdsk, etc.
I need just such a miniature one that I can always build it into my shaving machine.
Just don’t write that there are plenty of battery-powered and wind-up electric shavers on sale. My dear to me.
She's been with me half my life.
Good luck.
#30 root January 21 2018
To power a 220V electric razor from the car’s on-board network, it is better to assemble some more reliable and powerful voltage converter. Here are a few similar schemes:
- Voltage inverter 12V to 220V from available parts (555, K561IE8, MJ3001)
- Simple voltage inverter 13V-220V for car (CD4093, IRF530)
Thanks for the links, but it’s too expensive and difficult to assemble on your knees.
I don't have such details. But the old color.tel. and there is a tape recorder. It's all there
People write that you can increase the power by replacing transistors with 805.837.
An electric razor consumes 30 watts. Maybe it will. What do you think.
I came across the Variom A ROM.
The trouble is that the P216G transistors can no longer be found, and one of them is not working. According to the parameters, the GT701A seems to be suitable, but here’s how to determine the resistors. There are only 4 of them, two pairs. I don’t think it will work just replacing both P216Gs with GT701A. Tell.
#33 root February 05 2018
Agu1954, P216 transistors can be replaced with GT701A or P210V. Below are the main operating limits of these transistors:
- P216G: Ukb, max=50V; Ik max=7.5A; Pk max=24W; h21e>5; f gr.>0.2 MHz;
- P210V: Ukb, max=45V; Ik max=12A; Pk max=45W; h21e>10; f gr.>0.1 MHz;
- GT701A: Ukb, max=55V; Ik max=12A; Pk max=50W; h21e>10; f gp.=0.05 MHz;
Replace two transistors P216 with GT701A (P210V). For safety reasons, the first connection of the circuit to the battery should be made through a 3A fuse.
P.S. Please ask questions not related to the diagram given in the publication on the forum or in our social groups VK and FB.
#34 Sergey February 16 2018
#35 root February 16, 2018
Hello, Sergey. An old, and no longer working, postal address was indicated. Fixed it with a new one.
#36 Sergey February 16 2018
This converter operates at a frequency far greater than 50Hz. somewhere in the region of 20-50 kHz. Even if you increase the power by replacing transistors with more powerful ones, the razor will still not work. the engine simply cannot physically operate at a frequency of tens of kilohertz
#38 Petro Kopitonenko November 19 2018
To lower the frequency of the current on the converter, you must try to increase the number of turns of the transformer, both the primary and secondary windings. Where am I coming from? 50 hertz transformers have a large number of turns. And high-frequency ones have a small number of turns. This is the same as in oscillatory circuits, the frequency depends on the number of turns. I soldered an experimental converter with a factory transformer at 50 hertz. There, two primary windings are wound with 40 turns instead of 10 turns according to the circuit. I could hear the transformer humming at a frequency of about 40 hertz by ear. If it were a frequency of 50 kilohertz, I would not hear anything!!!
#39 David June 13 2019
Or you can use a ready-made transformer in this circuit. For example, step-up transformer TP 30-2, just connect in reverse (to the 15 volt output winding)
#40 root June 15 2019
The circuit requires a high-frequency transformer; TP 30-2 or another network transformer with Sh-like or toroidal iron will not work here.
Schematic diagram of the 12-220 inverter on TL494
This inverter uses a ready-made high-frequency step-down transformer from the computer’s power supply, but in our converter it will become, on the contrary, a step-up transformer. This transformer can be taken from both AT and ATX. Typically, such transformers differ only in size, and their pin locations are the same. You can look for a dead power supply (or a transformer from it) at any computer repair shop.
If you don’t find such a transformer, you can try winding it manually (if you have the patience). Here is the transformer I used in my version:
Transistors must be placed on a radiator, otherwise they may overheat and fail.
I used an aluminum radiator from a semiconductor Soviet TV. This radiator did not quite fit the size of the transistors, but I had no other option.
It is also advisable to insulate all high-voltage terminals of this inverter and it is better to assemble everything into a housing, because if this is not done, a short circuit may accidentally occur or you may simply touch the high-voltage terminal, which will be very unpleasant.
Be careful! The output of the circuit is high voltage and can cause a very serious shock.
I used a case from a laptop power supply. It fit very well in size.
And of course the inverter in action:
Good luck to everyone, Kirill.
There are completely different situations when the owner needs to create a new voltage converter at home. The main purpose of this device is to provide a mains voltage value of 220 V from the original values of 12 W. The 12 to 220 inverter is made by hand by most amateurs, since a good quality inverter is quite expensive. Before assembling the device, you should understand the principle of its operation in order to have an idea of the mechanism of its operation.
In what areas is a 12-220 V voltage inverter used?
With stable use of the battery, its charge level gradually decreases. The converter stabilizes the voltage if there is no electricity.
A 12-220 V inverter, made by yourself, will allow you to improve engineering structures in any room. The power value of devices that convert current is selected according to the total values of the operated loads. Power consumption processes can be reactive or active. Reactive loads do not fully consume the amount of energy received, causing the apparent power value to be greater than its active value.
Pure sine wave inverters are used when connecting an element whose total power is 3 kW. Significant fuel savings are ensured by the use of voltage converters and mini-power plants.
The following consumers are connected to the inverter design:
- alarm system;
- boiler;
- pumping apparatus;
- computer system.
Advantage of using voltage converters
Due to the fact that inverters have a number of positive characteristics, they are highly valued when used for various types of electrical equipment. The devices operate silently and do not pollute the environment with all kinds of emissions. The cost of servicing such devices is minimal: there is no need to check the pressure in the engine. Inverters have fairly insignificant mechanical wear, which allows them to be used by various consumers. Inverters 12-220 V operate at increased powers KR121 EU and have increased efficiency.
In the process of assembling inverters with master devices as multivibrators, the advantage of the converters is that the device is accessible and simple. The size of the products is compact, repairing them is not difficult, and they can be operated even at low temperatures.
Scheme and principle of operation of the inverter 12 220
The main part of radio components that use inverters use high frequencies in their operation. A pulse inverter completely replaces the classical circuit that uses transformers. The K561TM2 microcircuit is formed by two D-triggers, which have an R and S input. Such a microcircuit is created taking into account the use of CMOS technologies, by enclosing it in a plastic case.
The inverter master generators are mounted taking into account the K561TM2, using the DD1 device for operation. The DD1.2 trigger is mounted on the frequency divider. The amplification stages receive the signal from the microcircuits.
For operation, KT827 transistors are selected. If they are missing, then a transistor like KT819 GM or a field-effect semiconductor - IRFZ44 will do.
Generators with a sine wave for a 12-220 V inverter operate at high frequencies. To form a circuit with a size of 50 Hz, use a secondary winding with a parallel connection of capacitors and loads. By connecting any device, inverters create a conversion voltage of 220 V.
The circuit has one significant drawback - the imperfect form of the output parameters.
Speaking about how the 12 220 inverter works, it is worth pointing out that the K561TM2 chip is duplicated by the K564TM2. You can increase the power on the converter by selecting a more intense transistor. It is important to take into account the fact which capacitors are installed at the outputs. They have a voltage of 250 V.
Converter with the latest parts
A homemade inverter can operate in a stable mode if the transistor at the outputs operates from an amplified source with the main generator. For this purpose, it is allowed to use elements of the KT819GM series installed on dimensional radiators.
When creating converters, a simplified scheme is used. As the process progresses, you should take care of purchasing the necessary materials:
- microcircuits KR121EU1;
- transistors IRL2505;
- soldering iron;
- tin.
KR12116U1 microcircuits have a remarkable property: they contain a pair of channels for regulating the switch and allow you to quite simply make a simple voltage converter. Microcircuits in the temperature range from +25 to +30°C produce a maximum voltage value within the range of 3 and 9 V.
The frequency of the master oscillators is determined by the parameter of the element in the circuits. The IRL2505 transistor is installed when used on the outputs. It must receive a signal with the proper level, due to which the output transistor is adjusted.
The formed low levels do not allow the transistor to transition from closed modes to any other states. As a result, the occurrence of instantaneous current flows during simultaneous opening of the keys is completely eliminated. If high levels are observed to reach the first output, then this helps to turn off pulse generation. The circuit determines the connection of the common wire to pin 1.
To install push-pull cascades, T1 transformers and two transistors are used: VT1 and VT2. In open channels you can see a resistance value of 0.008 Ohm. It is insignificant, and therefore the power value of the transistor is small, even if a large current passes. Output transformers with a power of 100 W allow the IRL2505 to apply a current of 104 A, and pulse transformers are 360 A.
The main features of inverters include the ability to use any transformer that has two 12 V windings at its outputs.
If the output power is about 200 W, then in such cases the transistor is not installed on the radiator. It is important to consider that the value of electric current with a power of 400 W reaches about 40 A.
How does an inverter for fluorescent lamps work?
To make a converter that will illuminate a room of any size or car, it is enough to use a DIY assembly diagram. VOLTSL pulse converters are push-pull converters. They are mounted on power supplies TL 494 (KS 1114EU4). The microcircuits are controlled by the power parts of the power supply and consist of:
- voltage generator;
- voltage stabilizing source;
- two transistors on the output sources of electric current, the capacitance of which is 0.7 mm and 0.1 V.
To complete the installation, it is necessary to provide for the purchase of rectifier diodes and a transformer from the power supply. The issue of rewinding transformers should be addressed. When performing this work yourself, you should calculate up to 100 kHz. Each resistor is purchased, taking into account the circuit R1 and R2, creating the passage of a current pulse at the output. The operating frequency is formed when creating the circuit C1 and R3. HR307 diodes are mounted, but if they are not available, then use HER304. KD213 diodes have proven themselves quite well. The selection of capacitors is carried out with different capacities. Soldered chips are placed in panels. The circuits can operate for four hours - the design of the transistors does not overheat, and they do not need tuning.
Transformers are subject to independent winding. Therefore, it is necessary to stock up on ferrite rings with a diameter of 30 mm in advance. The basis uses a winding turns ratio of 1:120, while 1:1 is the primary winding and 20 is 200 turns with a secondary winding.
Initially, the secondary winding is wound using a wire with a cross-section of 0.4 mm. At the next stage, a primary coating is created, which consists of 2 halves of ten turns on each of them. Stranded soft wire with a diameter of 0.8 mm is used to create a half-winding. To remake the transformer, it is possible to use a device for a 12-volt lamp that illuminates the ceiling. The secondary winding is removed, and the half-winding is created by winding the coverings when the wire is folded in half. After this, the connecting point is cut, and each end of the wires is soldered together, thereby forming the center of the winding.
For uninterrupted operation, it is necessary to use powerful metal conductors or field-effect transistors IRFL44N LRF46N. For converters, diodes HER307 and KD213 are installed. Computer power supplies with a diameter of 18 mm are used as capacitors.
During prolonged operation, the transistors heat up and radiators are not installed. If it is intended to be used, then the flanges on the transistor housing should not be wrapped through resistors. You should use a washer and spacer insulating materials from PC power supplies.
Inverters are reliably protected from overload if a fuse and diode are installed at the outputs. It is important that safety regulations are strictly followed: that is, high voltages must be avoided. Charges in capacitors can be stored for 24 hours. Discharge is carried out using 220 V incandescent lamps.
A 12V 220 inverter with your own hands can be made according to a simple diagram. Such a device is considered a fairly convenient device that allows you to receive a voltage of 220 V. Any devices made at home, in some situations, are absolutely in no way inferior to factory-made products, and in some cases even surpass them.
Video “Creating a converter for fluorescent lamps”
Very often situations arise when it is necessary to connect an electronic device or device in a place where there is no mains voltage of 220 volts. The simplest thing is to use rechargeable batteries, but their voltage is usually 12 volts. In order to convert 12 volts to 220 volts, inverters are used, another name is converters. So, an inverter is an electronic device that converts low direct voltage into 220 V alternating voltage.
The options for using the inverter are varied:
- Application for providing power supply in case of emergency in the 220 volt network. Such a conversion system is installed in a country house or at industrial facilities.
- To organize complete autonomy from power grids.
- During long trips by car, bus, boat, plane.
The main difference between the devices used will be the power that can be connected in the form of a load and the electronic design.
Inverters differ in their construction scheme. The first devices were of a mechanical type, until they were replaced by semiconductor ones, and modern ones have already become digital. According to the classification, the following main construction schemes are distinguished:
They are also divided into single-phase and three-phase. By type of output voltage there are:
- with a rectangular shape;
- with a stepped shape;
- with a sinusoidal shape.
For devices that do not require a correct sinusoidal signal, converters with rectangular, trapezoidal, triangular output voltage can be used. The main advantage of such converters is their low price.
For equipment that requires reliable power supply, it is necessary to use inverters with the correct sine wave shape. Such equipment costs significantly more, but their operating stability is higher.
Selecting a voltage converter
When choosing, first of all you need to pay attention to power. The total power is calculated based on the load that is planned to be connected to the device; about 25-30 percent is added to the resulting value. This allows you to work in comfortable conditions, without overloading the equipment. An inverter with a power of up to 5000 W is usually used, but even 15,000 watts may not be enough to cover almost all household needs. For a portable device, 200-800 watts are used. In addition to rated power, there is the concept of peak power. This is a value that the inverter can withstand for a short time without negative consequences for its operation.
It is important to understand that the load power when turning on a number of devices differs from the nominal one. These are devices such as a pump, refrigerator, washing machine, and powerful vacuum cleaner. All of them consume peak power when turned on. At the same time, the TV, computer, lamp and tape recorder do not exceed the rated value during operation. It is also necessary to note this point: power can be measured both in volt-amperes (VA) and watts (W). The relationship between these units of measurement is described by the expression 1W=1.6VA.
So, first of all, when choosing, we determine for what type of device the current converter from 12 to 220 volts will be used. When operating indoors, we consider the possibility of installing rechargeable batteries. They must connect parallel to each other, this will ensure the possibility of continuous operation in case of problems in the industrial electrical network. For example, for an autonomous heating system.
Then we pay attention to the shape of the output signal. A pure sine wave indicates the frequency with which the voltage is applied and how smoothly it changes. This characteristic is very important for systems with active power - these are all devices using electric motors and compressors.
We pay attention to the options if desired, this could be the implementation of automatic on and off, charger function, protection against overvoltage, overheating, etc.
How to make a voltage converter with your own hands
As an example, consider converting an inverter from 12 to 220-3000 watts. It won’t be difficult to implement it with your own hands and with a little technical training. There are several ways to resolve this issue.
Manufacturing using radio-electric circuits
The electronic part is assembled on a printed circuit board, then a housing is made on which everything is attached. The operating principle of such converters is usually the same. A pulse width modulation (PWM) controller is used to set the frequency and amplitude. The power part is assembled from powerful transistors installed on radiators.
Let's consider an example using a generator whose output signal is used for synchronization. A specialized microcircuit kr1211eu1 is used as a generator. As output transistors operating in switching mode, you can use 2SK2554 or analogues BUZ111SL, BUK9608−55, IRL2505. The advantage of such field-effect transistors is the low resistance of the open channel RDS (on), which allows the use of radiators of small areas.
The r1, c1 chain sets the frequency of the generator, and r2, c2 is intended to start it. In this circuit, you can use any step-up transformer with secondary windings of 12 volts of the required power. Microcircuit power supply carried out through a stabilizer, the output voltage of which is achieved due to the strong nonlinearity of the current-voltage characteristics of electronic components consisting of r3, vd1, c3 with a stabilization voltage of 7-10 volts. Capacitor c6 is designed to reduce the influence of high-frequency interference.
You can connect any type of load to such a device, the power of which will not exceed 2.6 kW. Thus, having understood the operation of the circuit, you can not only assemble it, but also carry out repairs if necessary.
One more point needs to be noted: when assembling it yourself, you need to pay attention to the wires connected to the power source from the inverter. The more powerful the device is, the larger the wire cross-section should be. The main characteristic that helps calculate the wire cross-section is the maximum permissible continuous load (current). This is the current value that the wire can pass through itself for a long time without heating. In our case, for 3 kW it is recommended to use a wire with a cross-section of 2.5 square. Choose copper as the material.
Using an uninterruptible power supply
They come in different capacities, so there shouldn’t be any problems with selection. This is a ready-made inverter. For example, this type of device can be used in a car by connecting a car battery to the standard battery location.
Using ready-made nodes and blocks
In radio electronics stores you can find kits that allow you to get a finished device. The kit usually includes a factory printed circuit board, the necessary radio components, radiators, assembly instructions and settings. The finished 12,220 volt inverter will have to be placed in the housing after assembly. The housing must be selected based not only on aesthetic considerations, but also on the correct organization of cooling of the active parts.
Thus, you can independently manufacture voltage converters from 12 to 220 V. If done correctly, they will work no worse than industrially manufactured options.
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