Making homemade voltage stabilizers is a fairly common practice. However, for the most part, stabilizing electronic circuits are created, designed for relatively low output voltages (5-36 volts) and relatively low powers. Devices are used as part of household equipment, nothing more.

We will tell you how to make a powerful voltage stabilizer with your own hands. The article we have proposed describes the process of manufacturing a device for working with a mains voltage of 220 volts. Taking into account our advice, you can easily cope with the assembly yourself.

The desire to provide a stabilized voltage of the household network is an obvious phenomenon. This approach ensures the safety of operated equipment, often expensive, constantly needed in the economy. And in general, the stabilization factor is a guarantee of increased safety in the operation of electrical networks.

For domestic purposes, most often they are purchased, the automation of which requires a connection to the power supply, pumping equipment, split systems and similar consumers.

Industrial design line voltage stabilizer, which is easy to obtain on the market. The range of such equipment is huge, but there is always the opportunity to make your own design.

It is possible to solve such a problem different ways, the easiest of which is to buy a powerful voltage stabilizer, manufactured in an industrial way.

There are many offers on the commercial market. However, acquisition opportunities are often limited by the cost of devices or other points. Accordingly, an alternative to buying is assembling a voltage stabilizer with your own hands from available electronic components.

Provided that you have the appropriate skills and knowledge of electrical installation, the theory of electrical engineering (electronics), wiring circuits and soldering elements, a home-made voltage regulator can be implemented and successfully applied in practice. There are such examples.

Something like this may look like stabilization equipment made by hand from affordable and inexpensive radio components. Chassis and housing can be picked up from old industrial equipment (for example, from an oscilloscope)

Schematic solutions for stabilizing the electrical network 220V

Considering possible circuit solutions for voltage stabilization, taking into account the relatively high power (at least 1-2 kW), one should keep in mind the variety of technologies.

There are several circuit solutions that determine the technological capabilities of devices:

• ferroresonant;
• servo-driven;
• electronic;
• inverter.

Which option to choose depends on your preference, the materials available for assembly and skills in working with electrical equipment.

Option #1 - ferroresonant circuit

For self-manufacturing simple option circuit, the first item on the list is seen - a ferroresonant circuit. It works on the use of the effect of magnetic resonance.

Structural scheme a simple stabilizer made on the basis of chokes: 1 - the first choke element; 2 - the second throttle element; 3 - capacitor; 4 – input voltage side; 5 - output voltage side

The design of a sufficiently powerful ferroresonant stabilizer can be assembled on just three elements:

1. Throttle 1.
2. Throttle 2.
3. Capacitor.

However, the simplicity in this option accompanied by many inconveniences. The design of a powerful stabilizer, assembled according to a ferroresonance scheme, turns out to be massive, bulky, and heavy.

Option #2 - Autotransformer or Servo Drive

In fact, we are talking about a circuit that uses the principle of an autotransformer. Voltage transformation is automatically carried out by controlling a rheostat, the slider of which moves the servo.

In turn, the servo drive is controlled by a signal received, for example, from a voltage level sensor.

Schematic diagram of a servo-driven apparatus, the assembly of which will allow you to create a powerful voltage stabilizer for your home or country house. However, this option is considered technologically obsolete.

Approximately according to the same scheme, a relay type device operates with the only difference that the transformation ratio changes, if necessary, by connecting or disconnecting the corresponding windings using a relay.

Schemes of this kind already look more technically complex, but at the same time they do not provide sufficient linearity of voltage changes. It is permissible to manually assemble a relay or servo device. However, it is wiser to choose the electronic version. The costs of manpower and resources are almost the same.

Option # 3 - electronic circuit

The assembly of a powerful stabilizer according to the electronic control scheme with an extensive range of radio components on sale becomes quite possible. As a rule, such schemes are assembled on electronic components- triacs (thyristors, transistors).

Also designed whole line voltage stabilizer circuits, where power field-effect transistors are used as keys.

Block diagram of the electronic stabilization module: 1 - input terminals of the device; 2 – triac control unit for transformer windings; 3 - microprocessor unit; 4 - output terminals for connecting the load

It is quite difficult to make a powerful device completely under electronic control by the hands of a non-specialist, better. In this case, experience and knowledge in the field of electrical engineering is indispensable.

It is advisable to consider this option for independent production if there is a strong desire to build a stabilizer, plus the accumulated experience of an electronics engineer. Further in the article, we will consider the design of an electronic design suitable for do-it-yourself manufacturing.

Detailed assembly instructions

The circuit considered for self-production is rather a hybrid option, since it involves the use of a power transformer in conjunction with electronics. The transformer in this case is used from among those installed in older TVs.

Here is an approximately power transformer required for the manufacture of a home-made stabilizer design. However, the selection of other options or winding with your own hands is not excluded.

True, in TV receivers, as a rule, transformers TS-180 were installed, while the stabilizer requires at least TS-320 to provide an output load of up to 2 kW.

Step # 1 - making the stabilizer body

For the manufacture of the body of the device, any suitable box based on an insulating material - plastic, textolite, etc. is suitable. The main criterion is the sufficiency of space for the placement of the power transformer, electronic board and other components.

It is also permissible to make the case from sheet fiberglass by fastening individual sheets with the help of corners or in another way.

It is permissible to choose a case from any electronics, suitable for placing all the working components of the home-made stabilizer circuit. Also, the body can be assembled with your own hands, for example, from sheets of fiberglass

The stabilizer box must be equipped with grooves for installing a switch, input and output interfaces, as well as other accessories provided for by the circuit as control or switching elements.

Under the manufactured case, a base plate is needed, on which the electronic board will “lie down” and the transformer will be fixed. The plate can be made of aluminum, but insulators should be provided for fastening the electronic board.

Step #2 - Making the PCB

Here you will need to initially design a layout for the placement and connection of all electronic parts in accordance with circuit diagram except for the transformer. Then, a sheet of foil textolite is marked out according to the layout and the created trace is drawn (printed) on the side of the foil.

Fabricate the printed circuit board of the stabilizer completely accessible ways can be done directly at home. To do this, you need to prepare a stencil and a set of tools for etching on foil textolite

The printed copy of the wiring obtained in this way is cleaned, tinned, and all radio components of the circuit are mounted, followed by soldering. This is how the electronic board of a powerful voltage stabilizer is manufactured.

In principle, third-party PCB etching services can be used. This service is quite affordable, and the quality of the "signet" is significantly higher than in the home version.

Step #3 - Assembling the Voltage Regulator

The board equipped with radio components is being prepared for external binding. In particular, external communication lines (conductors) with other elements - a transformer, a switch, interfaces, etc. - are output from the board.

A transformer is installed on the base plate of the housing, the circuits of the electronic board are connected to the transformer, and the board is fixed on insulators.

An example of a home-made relay-type voltage regulator, made at home, placed in a case from a worn-out industrial measuring device

It remains only to connect to the circuit external elements mounted on the case, install the key transistor on the radiator, after which the assembled electronic structure is closed with the case. The voltage regulator is ready. You can start setting up with further tests.

The principle of operation and homemade test

Regulating element electronic circuit stabilization is a powerful field-effect transistor of the IRF840 type. The voltage for processing (220-250V) passes through the primary winding of the power transformer, is rectified by the VD1 diode bridge and goes to the drain of the IRF840 transistor. The source of the same component is connected to the negative potential of the diode bridge.

Schematic diagram of a high power stabilizing unit (up to 2 kW), on the basis of which several devices were assembled and successfully used. The circuit showed the optimal level of stabilization at the specified load, but not higher

Part of the circuit, which includes one of the two secondary windings of the transformer, is formed by a diode rectifier (VD2), a potentiometer (R5) and other elements of the electronic regulator. This part of the circuit generates a control signal that is fed to the gate of the IRF840 field effect transistor.

In the event of an increase in the supply voltage, the control signal lowers the gate voltage of the field-effect transistor, which leads to the closing of the key. Accordingly, on the load connection contacts (XT3, XT4), the possible increase in voltage is limited. The circuit works in reverse in case of a decrease in the mains voltage.

Setting up the device is not particularly difficult. Here you will need ordinary lamp incandescent (200-250 W), which should be connected to the output terminals of the device (X3, X4). Further, by rotating the potentiometer (R5), the voltage at the marked terminals is adjusted to a level of 220-225 volts.

Turn off the stabilizer, turn off the incandescent lamp and turn on the device already with a full load (not higher than 2 kW).

After 15-20 minutes of operation, the device is turned off again and the temperature of the radiator of the key transistor (IRF840) is monitored. If the heating of the radiator is significant (more than 75º), a more powerful heat sink radiator should be selected.

If the manufacturing process of the stabilizer seemed too complicated and irrational from a practical point of view, you can find and purchase a factory-made device without any problems. Rules and criteria are given in our recommended article.

Conclusions and useful video on the topic

The video below looks at one possible homemade stabilizer design.

In principle, you can take note of this version of a home-made stabilization apparatus:

Do-it-yourself assembly of a block that stabilizes the mains voltage is possible. This is confirmed by numerous examples when radio amateurs with little experience quite successfully develop (or use an existing one), prepare and assemble an electronics circuit.

Difficulties with the acquisition of parts for the manufacture of a homemade stabilizer are usually not noted. Production costs are low and will naturally pay off when the stabilizer is put into service.

Please leave comments, ask questions, publish photos on the topic of the article in the block below. Tell us about how you assembled the voltage regulator with your own hands. Share useful information, which may be useful to novice electrical engineers visiting the site.

Household devices are sensitive to power surges, wear out faster, and malfunctions appear. In the electrical network, the voltage often changes, decreases, or increases. This is interconnected with the remoteness of the energy source and low-quality power lines.

To connect devices to a sustainable power supply, voltage stabilizers are used in residential premises. At its output, the voltage has stable properties. The stabilizer can be purchased at the distribution network, but such a device can be made by hand.

There are tolerances for voltage change no more than 10% of the nominal value (220 V). This deviation must be observed both upwards and downwards. But there is no ideal electrical network, and the voltage value in the network often changes, thereby aggravating the operation of devices connected to it.

Electrical appliances react negatively to such vagaries of the network and can quickly fail, while losing their inherent functions. To avoid such consequences, people use homemade appliances called voltage regulators. An effective stabilizer was a device made on triacs. We will consider how to make a voltage stabilizer with our own hands.

Stabilizer characteristic

This stabilization device will not have increased sensitivity to changes in the voltage supplied through the common line. Voltage smoothing will be performed if the input voltage is in the range from 130 to 270 volts.

Devices connected to the network will be powered by a voltage ranging from 205 to 230 volts. From such a device it will be possible to power electrical devices, the total power of which is up to 6 kW. The stabilizer will switch the load of the consumer in 10 ms.

Stabilizer device

Scheme of the stabilization device.

The voltage stabilizer according to the specified scheme includes the following parts:

1. The power supply unit, which includes capacities C2, C5, a comparator, a transformer, a thermoelectric diode.
2. A node that delays the connection of the consumer's load, and consists of resistances, transistors, capacitance.
3. Rectifier bridge measuring voltage amplitude. The rectifier consists of a capacitance, a diode, a zener diode, and several dividers.
4. voltage comparator. His constituent parts are resistors and comparators.
5. Logic controller on microcircuits.
6. Amplifiers, on VT4-12 transistors, current-limiting resistors.
7. LEDs as indicators.
8. Optitronic keys. Each of the nicknames is supplied with triacs and resistors, as well as opto-triacs.
9. Electric machine or fuse.
10. Autotransformer.

Operating principle

Let's see how it works.

After the power is connected, the capacitance C1 is in a state of discharge, the transistor VT1 is open, and VT2 is closed. VT3 transistor also remains closed. Through it, current is supplied to all LEDs and an optitron based on triacs.

Since this transistor is in the closed state, the LEDs do not light up, and each triac is closed, the load is turned off. At this moment, the current flows through the resistance R1 and comes to C1. Then the capacitor begins to charge.

The shutter speed range is three seconds. During this period, all transition processes are performed. After their completion, the Schmitt trigger is activated based on transistors VT1 and VT2. After that, the 3rd transistor opens and the load is connected.

The voltage coming from the 3rd winding T1 is equalized by the diode VD2 and capacitance C2. Next, the current flows to the divider on the resistances R13-14. From the resistance R14, a voltage, the magnitude of which is directly dependent on the magnitude of the voltage, is included in each non-inverting comparator input.

The number of comparators becomes 8. They are all made on DA2 and DA3 chips. At the same time, the inverted input of the comparators is suitable D.C., fed with dividers R15-23. Next comes the controller, which receives the input signal of each comparator.

Voltage stabilizer and its features

When the input voltage drops below 130 volts, a small logic level appears at the outputs of the comparators. At this moment, the VT4 transistor is open, the first LED is blinking. This indication indicates the presence of low voltage, which means that the adjustable stabilizer cannot perform its functions.

All triacs are closed and the load is off. When the voltage is in the range of 130-150 volts, then signals 1 and A have the properties of a logic high value. This level has low value. In this case, the VT5 transistor opens, and the second LED starts to signal.

Optosimistor U1.2 opens in the same way as triac VS2. A load current will flow through the triac. Then the load will go into the upper output of the T2 autotransformer coil.

If the input voltage is 150 - 170 V, then signals 2, 1 and V have an increased logic level value. Other signals are low. With this input voltage, the transistor VT6 opens, the 3rd LED turns on. At this moment, the 2nd triac opens and the current flows to the second output of the T2 coil, which is the 2nd from the top.

A self-assembled voltage regulator for 220 volts will connect the windings of the 2nd transformer if the input voltage level reaches, respectively: 190, 210, 230, 250 volts. To make such a stabilizer, you need a 115 x 90 mm printed circuit board made of foil fiberglass.

The board image can be printed on the printer. Then, using an iron, this image is transferred to the board.

Manufacturing of transformers

You can make transformers T1 and T2 yourself. For T1, whose power is 3 kW, it is necessary to use a magnetic circuit with a cross section of 1.87 cm 2, and 3 wires of PEV - 2. The 1st wire with a diameter of 0.064 mm. They wind the first coil, with the number of turns 8669. The other 2 wires are used to form the remaining windings. The wires on them must be of the same diameter 0.185 mm, with the number of turns 522.

In order not to manufacture such transformers yourself, you can use ready-made versions of TPK - 2 - 2 x 12 V, connected in series.

To make a T2 transformer for 6 kW, a toroidal magnetic circuit is used. The winding is wound with PEV-2 wire with the number of turns 455. 7 taps must be brought out on the transformer. The first 3 of them are wound with 3 mm wire. The remaining 4 outlets are wound with tires with a cross section of 18 mm 2. With this wire section, the transformer will not heat up.

Branches are performed on such turns: 203, 232, 266, 305, 348 and 398. The turns are counted from the lower branch. In this case electricity the network should flow through the outlet of the 266th turn.

Details and materials

The remaining elements and parts of the stabilizer for self-assembly are purchased from the distribution network. Let's list them:

1. Triacs (optrons) MOS 3041 - 7 pcs.
2. Triacs BTA 41 - 800 V - 7 pcs.
3. KP 1158 EN 6A (DA1) stabilizer.
4. Comparator LM 339 N (for DA2 and DA3) – 2 pcs.
5. Diodes DF 005 M (for VD2 and VD1) - 2 pcs.
6. Wirewound resistors SP 5 or SP 3 (for R13, R14 and R25) - 3 pcs.
7. Resistors C2 - 23, with a tolerance of 1% - 7 pcs.
8. Resistors of any rating with a tolerance of 5% - 30 pcs.
9. Current-limiting resistors - 7 pcs, for passing a current of 16 milliamps (for R 41 - 47) - 7 pcs.
10. Electrolytic capacitors - 4 pcs (for C5 - 1).
11. Film capacitors (C4 - 8).
12. Switch equipped with a fuse.

Optocouplers MOS 3041 are replaced by MOS 3061. KR 1158 EN 6A stabilizer can be changed to KP 1158 EN 6B. Comparator K 1401 CA 1 can be installed as an analogue of LM 339 N. Instead of diodes, you can use KC 407 A.

Chip KR 1158 EN 6A must be installed on the heat sink. For its manufacture, an aluminum plate of 15 cm 2 is used. It is also necessary to install triacs on it. For triacs, it is allowed to use a common heat sink. The surface area must exceed 1600 cm 2 . The stabilizer must be equipped with a KR 1554 LP 5 microcircuit, which acts as a microcontroller. Nine LEDs are arranged so that they fall into the holes on the front panel of the device.

If the housing arrangement does not allow them to be installed in the manner shown in the diagram, then they are placed on the other side, where the printed tracks are located. LEDs must be installed of a flashing type, but non-flashing diodes can also be mounted, provided that they glow with a bright red light. For such purposes, apply AL 307 KM or L 1543 SRC - E.

You can assemble simpler versions of devices, but they will have certain features.

Advantages and disadvantages, differences from factory models

If you list the advantages of self-made stabilizers, then the main advantage is low cost. Instrument manufacturers often inflate prices, and their own assembly will cost less anyway.

Another advantage can be determined by such a factor as the possibility of a simple do-it-yourself repair of a device. After all, who, if not you, know better a device assembled by yourself.

In the event of a breakdown, the owner of the device will immediately find the defective element and replace it with a new one. The simple replacement of parts is created by such a factor that all parts were purchased in a store, so they can be easily bought again in any store.

The disadvantage of a self-assembled voltage stabilizer is to highlight its complex setting.

The simplest do-it-yourself voltage stabilizer

Consider how you can make your own 220 volt stabilizer with your own hands, with a few simple parts at hand. If the voltage in your electrical network is significantly reduced, then such a device will suit you just in time. To make it, you need a ready-made transformer, and a few simple parts. It is better to take such an example of a device as a note, as it turns out a good device with sufficient power, for example, for a microwave.

For refrigerators and various other home appliances lowering the mains voltage is very harmful, more than raising it. If you raise the value of the mains voltage using an autotransformer, then during the decrease in the mains voltage at the output of the device, the voltage will be normal. And if the voltage in the network becomes normal, then at the output we will get an increased voltage value. For example, let's take a transformer for 24 V. With a voltage on the line of 190 V, the output of the device will be 210 V, with a network value of 220 V, the output will be 244 V. This is quite acceptable and normal for the operation of household devices.

For manufacturing, we need the main part - this is a simple transformer, but not electronic. You can find it ready-made, or change the data on an existing transformer, for example, from a broken TV. The transformer will be connected according to the autotransformer circuit. The output voltage will be approximately 11% higher than the mains voltage.

In this case, care must be taken, since during a significant voltage drop in the network upwards, the output of the device will receive a voltage that significantly exceeds the allowable value.

The autotransformer will add only 11% to the mains line voltage. This means that the power of the autotransformer is also taken at 11% of the power of the consumer. For example, the microwave power is 700 watts, so we take a transformer of 80 watts. But it is better to take power with a margin.

The SA1 regulator makes it possible, if necessary, to connect the load of the consumer without an autotransformer. Of course, this is not a full-fledged stabilizer, but on the other hand, its manufacture does not require large investments and a lot of time.

The ideal option for the operation of power networks is to change the values ​​​​of current and voltage, both downward and upward, by no more than 10% of the nominal 220 V. But since jumps are characterized by large changes in reality, electrical appliances connected directly to the network are in danger of losing their design capabilities and even failure.

Use of special equipment will help to avoid troubles. But since it is very different high price, then many people prefer to assemble a voltage stabilizer made by themselves. How justified is such a step and what will be required for its implementation?

The design and principle of operation of the stabilizer

Instrument design

Having decided to assemble the device yourself, you will have to look inside the case of an industrial model. It consists of several main parts:

• transformer;
• Capacitors;
• Resistors;
• Cables for connecting elements and connecting the device.

The principle of operation of the simplest stabilizer is based on the operation of a rheostat. It raises or lowers the resistance depending on the current strength. More modern models have a wide range of functions and are able to fully protect household appliances from power surges.

Types of devices and their features

Types and their applications

The classification of equipment depends on the methods used to regulate the current. Since this value represents the directed motion of particles, it can be influenced by one of the following methods:

• mechanical;
• Impulse.

The first is based on Ohm's law. Devices whose work is based on it are called linear. They include two knees that are connected using a rheostat. The voltage applied to one element passes through the rheostat and thus appears on the other, from which it is supplied to consumers.

Devices of this type only allow you to set the output current parameters and can be upgraded with additional nodes. But it is impossible to use such stabilizers in networks where the difference between the input and output current is large, since they will not be able to protect household appliances from short circuits at high loads.

We watch the video, the principle of operation of a pulsed device:

Impulse models work on the principle amplitude modulation current. The stabilizer circuit uses a switch that breaks it at regular intervals. This approach allows you to evenly accumulate current in the capacitor, and after it full charge and on to appliances.

Unlike linear stabilizers, pulse regulators do not have the ability to set a certain value. On sale there are step-down models - these are perfect choice for home.

Also, voltage stabilizers are divided into:

1. Single-phase;
2. Three-phase.

But since most household appliances operate from a single-phase network, in residential premises they usually use equipment belonging to the first type.

Let's start assembling: components, tools

Since the triac apparatus is considered the most effective, in our article we will consider how to independently assemble just such a model. It should be noted right away that this do-it-yourself voltage regulator will equalize the current, provided that the input voltage is in the range from 130 to 270V.

The permissible power of devices connected to such equipment cannot exceed 6 kW. In this case, the load switching will be carried out in 10 milliseconds.

As for the components, the following elements will be needed to assemble such a stabilizer:

• Power Supply;
• Rectifier for voltage amplitude measurement;
• Comparator;
• Controller;
• Amplifiers;
• LEDs;
• Load turn-on delay unit;
• autotransformer;
• Optocoupler keys;
• Safety switch.

Of the tools I will need a soldering iron and tweezers.

Manufacturing steps

To assemble a 220V voltage regulator for your home with your own hands, you first need to prepare a printed circuit board measuring 115x90 mm. It is made of foil fiberglass. Parts layout can be printed on laser printer and with the help of an iron transferred to the board.

We watch the video, a home-made simple device:

circuit diagram

• magnetic circuit with a cross-sectional area of ​​​​1.87 cm²;
• three PEV-2 cables.

The first wire is used to create one winding, while its diameter is 0.064 mm. The number of turns should be 8669.

The two remaining wires will be required to complete the other windings. They differ from the first one with a diameter of 0.185 mm. The number of turns for these windings will be 522.

If you want to simplify your task, then you can use two ready-made transformers TPK-2-2 12V. They are connected in series.

In the case of manufacturing these parts on their own, after one of them is ready, they proceed to the creation of the second. It will need a toroidal magnetic circuit. For the winding, the same PEV-2 is chosen as in the first case, only the number of turns will be 455.

Also, in the second transformer, 7 taps will have to be made. Moreover, for the first three, a wire with a diameter of 3 mm is used, and for the rest - tires with a cross section of 18 mm². This will help to avoid heating the transformer during operation.

connection of two transformers

All other components for a do-it-yourself device are best purchased in a store. After everything you need is purchased, you can start assembling. It is best to start by installing a microcircuit that acts as a controller on a heat sink, which is made of aluminum platinum with an area of ​​\u200b\u200bmore than 15 cm². Triacs are also mounted on it. Moreover, the heat sink on which they are supposed to be installed must have a cooling surface.

If assembling a 220V triac voltage regulator with your own hands seems difficult for you, then you can stop at a simpler linear model. It will have the same properties.

The effectiveness of a handmade product

What pushes a person to make a particular device? Most often - its high cost. And in this sense, a self-assembled voltage regulator, of course, surpasses the factory model.

To the benefits homemade devices can include the possibility of self-repair. The person who assembled the stabilizer understood both its principle of operation and structure and therefore will be able to fix the malfunction without outside help.

In addition, all parts for such a device were pre-purchased in the store, so if they fail, you can always find a similar one.

If we compare the reliability of a stabilizer assembled by ourselves and produced at the enterprise, then here the advantage is on the side of the factory models. At home, it is almost impossible to develop a model with high performance, since there is no special measuring equipment.

Conclusion

Exist different types voltage stabilizers, and some of them are quite realistic to do with your own hands. But for this you will have to understand the nuances of the equipment, purchase the necessary components and perform their competent installation. If you are not confident in your abilities, then the best option is to purchase a factory-made device. Such a stabilizer is more expensive, but also significantly superior in quality to models assembled independently.

The voltage of the home electrical network is often low, never reaching normal 220 V. In such a situation, the refrigerator does not start well, the lighting is weak, and the water in the electric kettle for a long time does not boil. The power of an outdated voltage regulator designed to power a black-and-white (tube) TV is usually insufficient for all other household appliances, and the mains voltage often drops below the allowable voltage for such a stabilizer.

There is a simple way to increase the voltage in the network, using a transformer with a power much less than the load power. The primary winding of the transformer is connected directly to the network, and the load is connected in series with the secondary (step-down) winding of the transformer. With appropriate phasing, the voltage at the load will be equal to the sum of the network and taken from the transformer.

Scheme of the mains voltage stabilizer operating on this principle is shown in Fig. 1. When the field-effect transistor VT2 included in the diagonal of the diode bridge VD2 is closed, the winding I (primary) of the transformer T1 is disconnected from the network. The voltage at the load is almost equal to the mains voltage, minus a small voltage drop on the winding II (secondary) of the transformer T1. If you open the field-effect transistor, the power supply circuit of the primary winding of the transformer will be closed, and the sum of the voltage of its secondary winding and the mains is applied to the load.

Rice. one Voltage stabilizer circuit

The voltage at the load, reduced by the transformer T2 and rectified by the diode bridge VD1, is fed to the base of the transistor VT1. The engine of the trimmer resistor R1 must be set to a position in which the transistor VT1 is open, and VT2 is closed if the voltage at the load is greater than the nominal (220 V). At a voltage less than the nominal transistor VT1 will be closed, and VT2 - open. Thus organized negative I Feedback maintains the voltage on the load approximately equal to the nominal

The voltage rectified by the VD1 bridge is also used to power the collector circuit of the transistor VT1 (through the integral stabilizer DA1). The C5R6 circuit suppresses unwanted drain-source voltage surges of the transistor VT2. Capacitor C1 reduces interference that enters the network during the operation of the stabilizer. Resistors R3 and R5 are selected to achieve the best and most stable voltage stabilization. Switch SA1 turns on and off the stabilizer along with the load. By closing the SA2 switch, the automation is turned off, which maintains the voltage at the load unchanged. In this case, it becomes the maximum possible at a given voltage in the network.

Most parts of the stabilizer are mounted on printed circuit board shown in fig. 2. The rest connect with it at points A-D.

Choosing a replacement for the diode bridge KTS405A(VD2), it should be borne in mind that it must be rated for a voltage of at least 600 V and a current equal to the maximum load current divided by the transformation ratio of the transformer T1. The requirements for the VD1 bridge are more modest: voltage and current - at least 50 V and 50 mA, respectively

Rice. 2 PCB mounting

Transistor KT972A can be replaced by KT815B, a IRF840- on the IRF740. Field-effect transistor has a heat sink with dimensions of 50x40 mm.

The "booster" transformer T1 is made of the ST-320 transformer, which was used in the power supplies BP-1 of the ULPCT-59 TVs. The transformer is disassembled, and the secondary windings are carefully wound, leaving the primary windings intact. New secondary windings (the same on both coils) are wound with enameled copper wire (PEL or PEV) in accordance with the data given in the table. The more the voltage drops in the network, the more turns will be required and the lower the permissible load power.

After rewinding and assembling the transformer, the terminals 2 and 2 "of the halves of the primary winding, located on different rods of the magnetic circuit, are connected by a jumper. The halves of the secondary winding must be connected in series so that their total voltage is maximum (if the connection is incorrect, it will be close to zero). By the maximum of the total voltage of the secondary winding and the network, it is necessary to determine which of the remaining free terminals of this winding should be connected to terminal 1 of the primary, and which to the load.

Transformer T2 - any network with a voltage on the secondary winding close to that indicated in the diagram with a current consumed from this winding of 5O ... 1OmA.

Table 1

Additional voltage, V	70	60	50	40	30	20
Maximum load power, kW	1	1.2	1.4	1,8	2,3	3,5
Number of winding turns II	60+60	54+54	48+48	41+41	32+32	23+23
Wire diameter, mm	1.5	1,6	1,8	2	2,2	2,8

By including assembled stabilizer into the network, set the voltage at the load to 220 V with a trimming resistor R1. It should be borne in mind that the described device does not eliminate fluctuations in the mains voltage if it exceeds 220 V or falls below the minimum adopted in the calculation of the transformer.

A stabilizer installed in a damp room must be placed in a grounded metal case.

Note: in heavy operating modes of the stabilizer, the power dissipated by the VT2 transistor can be very increased. It is she, and not the power of the transformer, that can limit the permissible load power. Therefore, you should take care of a good heat sink of the transistor.

The stabilizer is a network autotransformer, the winding taps of which are switched automatically depending on the voltage in the mains.

The stabilizer allows you to maintain the output voltage at the level of 220V when the input voltage changes from 180 to 270 V. The stabilization accuracy is 10V.

The circuit diagram can be divided into low current circuit (or control circuit) and high current circuit (or autotransformer circuit).

The control circuit is shown in Figure 1. The role of the voltage meter is assigned to a polycomparator microcircuit with a linear voltage indication, - A1 (LM3914).

Mains voltage is supplied to the primary winding of a low-power transformer T1. This transformer has two secondary windings, 12V each, with one common terminal (or one 24V winding with a tap from the middle).

The rectifier on the diode VD1 is used to obtain the supply voltage. The voltage from the capacitor C1 is supplied to the power supply circuit of the A1 chip and the LEDs of the H1.1-H9.1 optocouplers. And also, it serves to obtain exemplary stable voltages of the minimum and maximum scale marks. To obtain them, a parametric stabilizer on US and P1 is used. The measurement limits are set by trimmer resistors R2 and R3 (resistor R2 - upper value, resistor RЗ -lower).

The measured voltage is taken from the other secondary winding of the transformer T1. It is rectified by the VD2 diode and fed to the resistor R5. It is by the level of constant voltage across the resistor R5 that the degree of deviation of the mains voltage from the nominal value is assessed. During the adjustment process, the resistor R5 is preliminarily set to the middle position, and the resistor R3 to the lower position according to the scheme.

Then, an increased voltage (about 270V) is applied to the primary winding T1 from an autotransformer of the LATR type (about 270V) and the resistor R2 sets the scale of the microcircuit to the value at which the LED connected to pin 11 lights up (temporarily instead of optocoupler LEDs you can connect ordinary light diodes). Then the input alternating voltage is reduced to 190V and the scale is brought to the value by the resistor R3 when the LED connected to pin 18 A1 is on.

If the above settings fail, you need to adjust a little R5 and repeat them again. So, by successive approximations, a result is achieved when a change in the input voltage by 10V corresponds to switching the outputs of the A1 chip.

In total, nine threshold values ​​are obtained - 270V, 260V, 250V, 240V, 230V, 220V, 210V, 200V, 190V.

The schematic diagram of the autotransformer is shown in Figure 2. It is based on a converted transformer of the LATR type. The transformer housing is disassembled and the slider contact, which serves to switch taps, is removed. Then, based on the results of preliminary measurements of the voltages from the taps, conclusions are drawn (from 180 to 260V in 10V steps), which are subsequently switched using triac switches VS1-VS9, controlled by the control system via optocouplers H1-H9. The optocouplers are connected in such a way that when the reading of the A1 microcircuit decreases by one division (by 10V), it switches to a step-up (by the next 10V) tap of the autotransformer. And vice versa - an increase in the readings of the A1 microcircuit leads to switching to a step-down tap of the autotransformer. By selecting the resistance of the resistor R4 (Fig. 1), the current through the LEDs of the optocouplers is set, at which the triac switches switch confidently. The circuit on transistors VT1 and VT2 (Fig. 1) serves to delay the switching on of the autotransformer load for the time required to complete the transients in the circuit after switching on. This circuit delays the connection of the optocoupler LEDs to power.

Instead of the LM3914 chip, you cannot use similar LM3915 or LM3916 chips, due to the fact that they work according to the logarithmic law, but here you need a linear one, like the LM3914. Transformer T1 - small Chinese transformer type TLG, for primary voltage 220V and two secondary 12V each (12-0-12V) and current 300mA. You can use another similar transformer.

The T2 transformer can be made from LATR, as described above, or you can wind it yourself.

Other triacs can be used - it all depends on the load power. You can even use electromagnetic relays as switching elements.

By making other settings with resistors R2, R3, R5 (Fig. 1) and, accordingly, other taps T2 (Fig. 2), you can change the voltage switching step.

Krivosheim N. Radio designer. 2006 No. 6.

Literature:

1. Andreev S. Universal logical probe, f. Radioconstructor 09-2005.
2. Godin A. Stabilizer AC voltage, and. Radio, №8, 2005

P.S. In our "Master's Store" you can purchase ready-made modules for stabilizers, amplifiers, voltage and current indicators, as well as various amateur radio kits for self-assembly.

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