Schematic diagram of the power regulator. DIY power regulator for a soldering iron - diagrams and installation options

A small semiconductor device “triac”, or symmetrical thyristor (thyristor), behind its complex name hides a fairly simple principle of operation, comparable to the operation of a subway door. Ordinary thyristors can be compared to a simple door: if you close it, there will be no passage. And such a door works in one direction. Triacs work in both directions. That is why the comparison is with a door in the subway: wherever it is pushed, it comes off and allows the flow of passengers in any direction.

The two-way action of the triac is due to its special structure. Its cathode and anode are able, in a sense, to change places and perform each other's functions, passing current in the opposite direction. This is possible due to the fact that the triac has 5 semiconductor layers and a control electrode.

To make it easier to understand the physical processes occurring in a triac, you can imagine it in the form of two back-to-back thyristors connected in parallel.

Triacs are used in various circuits as contactless keys and have a number of advantages over contactors, relays, starters and similar electromechanical elements:

triacs are durable, practically indestructible;
where there are electromechanics, there are restrictions on the frequency of switching, wear, and corresponding risks and problems, but with semiconductors such nuances do not arise;
complete absence of sparking and associated risks;
the ability to carry out switching at moments of zero mains current, which reduces interference and the impact on the accuracy of the circuits.

Diagram of a simple power regulator using a triac

Most often, triacs are used in power control circuits. One of the simplest and most common power regulators on the KU208G triac is shown below.

As can be seen in the figure, the power circuit of the circuit is equipped with a KU208 type triac, and its control circuit includes only one element - a P416A type transistor. Setting up the operation of the device ultimately comes down to selecting the value of resistor R1 and proceeds in the following sequence:

set the resistor R4 slider to the lower position;
instead of resistor R1, install a variable resistor with a resistance of 150 Ohms;
set the variable resistor to the maximum position;
connect an AC voltmeter to the load;
connect the device to the network.

In order to connect it correctly, it must correspond to the pre-selected installation location and the number of connected devices. It is very important to check the correct operation of the lighting devices and adjust the corresponding sensor parameters.

This equipment, thanks to its technological qualities, is gaining increasing popularity when arranging lighting at home. After reading, you can understand the principle of operation of various motion sensors, which will help in the further selection of a suitable device for your home.

Next, you need to rotate the slider of resistor R1 and monitor the voltage on the load: you need to ensure that it stops increasing. In the found position, it is necessary to measure the resistance of the variable resistor, and accordingly the required resistance of resistor R1 will be set. It is with this value that it will be necessary to install a constant resistor R1 in the circuit in place of the variable sample.

Feedback in triac control circuits

To control the power (temperature) of heating elements of various devices, motor rotation speeds, etc. Recently, despite the higher cost than electromechanics, a power regulator based on a triac is used. The need to use an additional radiator for such a circuit is a small price to pay in exchange for the absence of risks of sparking, a long period of trouble-free operation, and the stability of the output parameters.

This control scheme is common in devices such as soldering irons, electric drills, etc.

Below is an example of another power control circuit using a triac. This is a circuit for controlling the speed of an industrial sewing machine motor.

The circuit is assembled using a triac VS1, rectifier valves VD1 and VD2, and a variable resistor R3 in the control circuit. The peculiarity and key distinguishing feature of such a scheme is feedback. A triac that passes current in both directions is the best solution for control circuits where such feedback is necessary.

When choosing the type of protective devices, first of all, their technical installation capabilities are taken into account in combination with individual preferences. This is decisive in resolving the question: ? Only by studying the features of their operation can you achieve safe functioning of the household electrical network.

When using residual current devices at home, you need to know the features of its various types in order to do it correctly, and also study the installation diagrams in order to do it correctly.

Comparing with outdated switching technologies, we can identify another clear advantage of power control circuits using triacs - the ability to provide high-quality feedback and, accordingly, adjust the operation based on feedback.

Features and advantages of the scheme:

In this case it is implemented load feedback, which allows you to increase engine speed and ensure smooth, uninterrupted operation of the machine in the event of increasing load forces. In this case, all operations are performed automatically by the circuit. There is no sparking or overheating. As can be seen from the figure, no heat sink is provided.

This scheme is regulation of active power of devices. The use of such circuits in lighting intensity control systems is not recommended. For a number of reasons, lights will flicker excessively.

Triac switching in this circuit it occurs strictly at the moments of transition through “0” of the mains voltage, so we can declare the complete absence of interference from the regulator.
It is put into action, that is triac turns on from a positive pulse arriving at the control electrode with a positive voltage at the anode, or from a negative pulse with a negative position at the cathode. The cathode and anode, taking into account the features of the bidirectional operation of the triac, are conditional here. depending on work in different directions, they will change functions.
Can be used as a source of pulses to control a triac bidirectional dinistor. Or, for reasons of reducing the cost of the circuit, you can connect a pair of ordinary dinistors in an anti-parallel direction. To ensure a wider range of regulation of low voltages, the optimal choice would be dinistors of the KNR102A type. Another option for the key element is an avalanche transistor.
Active and reactive power regulation have some distinctive features. Controlling an inductive load requires the inclusion of an RC circuit in the circuit (in parallel with the triac). This will allow you to restrain the rate of increase in voltage at the anode of the triac.

Video about triac power regulator

To control some types of household appliances (for example, a power tool or a vacuum cleaner), a power regulator based on a triac is used. You can learn more about the operating principle of this semiconductor element from the materials posted on our website. In this publication we will consider a number of issues related to triac circuits for controlling load power. As always, let's start with theory.

The principle of operation of the regulator on a triac

Let us recall that a triac is usually called a modification of a thyristor that plays the role of a semiconductor switch with a nonlinear characteristic. Its main difference from the basic device is two-way conductivity when switching to the “open” operating mode, when current is supplied to the control electrode. Thanks to this property, triacs do not depend on voltage polarity, which allows them to be used effectively in circuits with alternating voltage.

In addition to the acquired feature, these devices have an important property of the base element - the ability to maintain conductivity when the control electrode is disconnected. In this case, the “closing” of the semiconductor switch occurs when there is no potential difference between the main terminals of the device. That is, when the alternating voltage crosses the zero point.

An additional bonus from this transition to the “closed” state is the reduction in the amount of interference during this phase of operation. Please note that a regulator that does not create interference can be created under the control of transistors.

Thanks to the properties listed above, it is possible to control the load power by phase control. That is, the triac opens every half-cycle and closes when crossing zero. The delay time for turning on the “open” mode, as it were, cuts off part of the half-cycle, as a result, the shape of the output signal will be sawtooth.

In this case, the signal amplitude will remain the same, which is why it is incorrect to call such devices voltage regulators.

Regulator circuit options

Let's give a few examples of circuits that allow you to control load power using a triac, starting with the simplest.

Figure 2. Diagram of a simple triac power regulator powered by 220 V

Designations:

Resistors: R1- 470 kOhm, R2 – 10 kOhm,
Capacitor C1 – 0.1 µF x 400 V.
Diodes: D1 – 1N4007, D2 – any indicator LED 2.10-2.40 V 20 mA.
Dinistor DN1 – DB3.
Triac DN2 - KU208G, you can install a more powerful analog BTA16 600.

With the help of dinistor DN1, the circuit D1-C1-DN1 is closed, which moves DN2 to the “open” position, in which it remains until the zero point (completion of the half-cycle). The opening moment is determined by the accumulation time on the capacitor of the threshold charge required to switch DN1 and DN2. The rate of charge C1 is controlled by the chain R1-R2, the total resistance of which determines the moment of “opening” of the triac. Accordingly, the load power is controlled through a variable resistor R1.

Despite the simplicity of the circuit, it is quite effective and can be used as a dimmer for filament lighting or a soldering iron power regulator.

Unfortunately, the above circuit does not have feedback, therefore, it is not suitable as a stabilized speed controller of a commutator electric motor.

Feedback regulator circuit

Feedback is necessary to stabilize the speed of the electric motor, which can change under the influence of load. You can do this in two ways:

Install a tachometer that measures the speed. This option allows for precise adjustment, but this increases the cost of implementing the solution.
Monitor voltage changes on the electric motor and, depending on this, increase or decrease the “open” mode of the semiconductor switch.

The latter option is much easier to implement, but requires slight adjustment to the power of the electric machine used. Below is a diagram of such a device.

Designations:

Resistors: R1 – 18 kOhm (2 W); R2 – 330 kOhm; R3 – 180 Ohm; R4 and R5 – 3.3 kOhm; R6 – must be selected as described below; R7 – 7.5 kOhm; R8 – 220 kOhm; R9 – 47 kOhm; R10 – 100 kOhm; R11 – 180 kOhm; R12 – 100 kOhm; R13 – 22 kOhm.
Capacitors: C1 – 22 µF x 50 V; C2 – 15 nF; C3 – 4.7 µF x 50 V; C4 – 150 nF; C5 – 100 nF; C6 – 1 µF x 50 V..
Diodes D1 – 1N4007; D2 – any 20 mA indicator LED.
Triac T1 – BTA24-800.
Microcircuit – U2010B.

This circuit ensures a smooth start of the electrical installation and protects it from overload. Three operating modes are allowed (set by switch S1):

A – When overload occurs, LED D2 turns on, indicating overload, after which the engine reduces speed to minimum. To exit the mode, you must turn off and turn on the device.
B – If there is an overload, LED D2 turns on, the motor is switched to work at minimum speed. To exit the mode, it is necessary to remove the load from the electric motor.
C – Overload indication mode.

Setting up the circuit comes down to selecting resistance R6; it is calculated depending on the power of the electric motor using the following formula: . For example, if we need to control a 1500 W motor, then the calculation will be as follows: 0.25 / (1500 / 240) = 0.04 Ohm.

To make this resistance, it is best to use nichrome wire with a diameter of 0.80 or 1.0 mm. Below is a table that allows you to select the resistance R6 and R11, depending on the engine power.

The above device can be used as a speed controller for motors of power tools, vacuum cleaners and other household equipment.

Regulator for inductive load

Those who try to control an inductive load (for example, a welding machine transformer) using the above circuits will be disappointed. The devices will not work, and the triacs may fail. This is due to a phase shift, which is why during a short pulse the semiconductor switch does not have time to switch to the “open” mode.

There are two options to solve the problem:

Supplying a series of similar pulses to the control electrode.
Apply a constant signal to the control electrode until it passes through zero.

The first option is the most optimal. Here is a diagram where this solution is used.

As can be seen from the following figure, which shows oscillograms of the main signals of the power regulator, a packet of pulses is used to open the triac.

This device makes it possible to use regulators on semiconductor switches to control an induction load.

A simple power regulator on a triac with your own hands

At the end of the article, we will give an example of a simple power regulator. In principle, you can assemble any of the above circuits (the most simplified version was shown in Figure 2). For this device it is not even necessary to make a printed circuit board; the device can be assembled by surface mounting. An example of such an implementation is shown in the figure below.

This regulator can be used as a dimmer, and can also be used to control powerful electric heating devices. We recommend choosing a circuit in which a semiconductor switch with characteristics corresponding to the load current is used for control.

Many soldering irons are sold without a power regulator. When turned on, the temperature rises to maximum and remains in this state. To adjust it, you need to disconnect the device from the power source. In such soldering irons, the flux instantly evaporates, oxides are formed and the tip is in a constantly dirty state. It has to be cleaned frequently. Large components require high temperatures to solder, but small parts can be burned. To avoid such problems, power regulators are made.

How to make a reliable power regulator for a soldering iron with your own hands

Power controls help control the heat level of the soldering iron.

Connecting a ready-made heating power controller

If you do not have the opportunity or desire to tinker with the manufacture of the board and electronic components, then you can buy a ready-made power regulator at a radio store or order it on the Internet. The regulator is also called a dimmer. Depending on the power, the device costs 100–200 rubles. You may need to modify it a little after purchase. Dimmers up to 1000 W are usually sold without a cooling radiator.

Power regulator without radiator

And devices from 1000 to 2000 W with a small radiator.

Power regulator with small heatsink

And only the more powerful ones are sold with large radiators. But in fact, a dimmer from 500 W should have a small cooling radiator, and from 1500 W large aluminum plates are already installed.

Chinese power regulator with large radiator

Please take this into account when connecting the device. If necessary, install a powerful cooling radiator.

Modified power regulator

To correctly connect the device to the circuit, look at the back of the circuit board. The IN and OUT terminals are indicated there. The input is connected to a power outlet, and the output to a soldering iron.

Designation of input and output terminals on the board

The regulator is installed in different ways. To implement them, you do not need special knowledge, and the only tools you need are a knife, a drill and a screwdriver. For example, you can include a dimmer in the power cord of a soldering iron. This is the easiest option.

Cut the soldering iron cable into two parts.
Connect both wires to the board terminals. Screw the section with the fork to the entrance.
Select a plastic case of suitable size, make two holes in it and install the regulator there.

Another simple way: you can install the regulator and socket on a wooden stand.

You can connect not only a soldering iron to such a regulator. Now let's look at a more complex, but compact option.

Take a large plug from an unnecessary power supply.
Remove the existing board with electronic components from it.
Drill holes for the dimmer handle and two terminals for the input plug. The terminals are sold at a radio store.
If your regulator has indicator lights, make holes for them too.
Install the dimmer and terminals into the plug body.
Take a portable socket and plug it in. Insert the plug with the regulator into it.

This device, like the previous one, allows you to connect different devices.

Homemade two-stage temperature controller

The simplest power regulator is a two-stage one. It allows you to switch between two values: maximum and half of maximum.

Two-stage power regulator

When the circuit is open, current flows through diode VD1. The output voltage is 110 V. When the circuit is closed with switch S1, the current bypasses the diode, since it is connected in parallel and the output voltage is 220 V. Select the diode in accordance with the power of your soldering iron. The output power of the regulator is calculated by the formula: P = I * 220, where I is the diode current. For example, for a diode with a current of 0.3 A, the power is calculated as follows: 0.3 * 220 = 66 W.

Since our block consists of only two elements, it can be placed in the body of the soldering iron using hinged mounting.

Solder parallel parts of the microcircuit to each other directly using the legs of the elements themselves and the wires.
Connect to the chain.
Fill everything with epoxy resin, which serves as an insulator and protection against movement.
Make a hole in the handle for the button.

If the housing is very small, use a light switch. Mount it into the soldering iron cord and insert a diode parallel to the switch.

Switch for lamp

On a triac (with indicator)

Let's look at a simple triac regulator circuit and make a printed circuit board for it.

Triac power regulator

PCB manufacturing

Since the circuit is very simple, there is no point in installing a computer program for processing electrical circuits just because of it. Moreover, special paper is needed for printing. And not everyone has a laser printer. Therefore, we will take the simplest route of manufacturing a printed circuit board.

Take a piece of PCB. Cut to the size required for the chip. Sand the surface and degrease.
Take a laser disc marker and draw a diagram on the PCB. To avoid mistakes, draw with a pencil first.
Next, we start etching. You can buy ferric chloride, but the sink is difficult to clean after it. If you accidentally drop it on your clothes, it will leave stains that cannot be completely removed. Therefore, we will use a safe and cheap method. Prepare a plastic container for the solution. Pour in 100 ml hydrogen peroxide. Add half a tablespoon of salt and a packet of citric acid up to 50 g. The solution is made without water. You can experiment with proportions. And always make a fresh solution. All copper should be removed. This takes about an hour.
Rinse the board under running water. Dry. Drill the holes.
Wipe the board with alcohol-rosin flux or a regular solution of rosin in isopropyl alcohol. Take some solder and tin the tracks.

To apply the diagram on PCB, you can make it even easier. Draw a diagram on paper. Glue it with tape to the cut out PCB and drill holes. And only after that draw the circuit with a marker on the board and etch it.

Installation

Prepare all necessary components for installation:

solder spool;
pins into the board;
triac bta16;
100 nF capacitor;
2 kOhm fixed resistor;
dinistor db3;
variable resistor with a linear dependence of 500 kOhm.

Proceed to install the board.

Cut off four pins and solder them into the board.
Install the dinistor and all other parts except the variable resistor. Solder the triac last.
Take a needle and brush. Clean the gaps between the tracks to remove any possible shorts.
Take an aluminum radiator to cool the triac. Drill a hole in it. The triac with its free end with a hole will be attached to an aluminum radiator for cooling.
Use fine sandpaper to clean the area where the element is attached. Take heat-conducting paste of the KPT-8 brand and apply a small amount of paste to the radiator.
Secure the triac with a screw and nut.
Carefully bend the board so that the triac takes a vertical position in relation to it. To make the design compact.
Since all parts of our device are under mains voltage, we will use a handle made of insulating material for adjustment. It is very important. Using metal holders here is dangerous to life. Place the plastic handle on the variable resistor.
Use a piece of wire to connect the outer and middle terminals of the resistor.
Now solder two wires to the outer terminals. Connect the opposite ends of the wires to the corresponding pins on the board.
Take the socket. Remove the top cover. Connect the two wires.
Solder one wire from the socket to the board.
And connect the second one to the wire of a two-core network cable with a plug. The power cord has one free core left. Solder it to the corresponding pin on the printed circuit board.

In fact, it turns out that the regulator is connected in series to the load power circuit.

Connection diagram of the regulator to the circuit

If you want to install an LED indicator in the power regulator, then use a different circuit.

Power regulator circuit with LED indicator

Diodes added here:

VD 1 - diode 1N4148;
VD 2 - LED (operation indication).

The triac circuit is too bulky to be included in a soldering iron handle, as is the case with a two-stage regulator, so it must be connected externally.

Installation of the structure in a separate housing

All elements of this device are under mains voltage, so a metal case cannot be used.

Take a plastic box. Outline how the board with the radiator will be placed in it and which side to connect the power cord from. Drill three holes. The two extreme ones are needed to attach the socket, and the middle one is for the radiator. The head of the screw to which the radiator will be attached must be hidden under the socket for electrical safety reasons. The radiator has contact with the circuit, and it has direct contact with the network.
Make another hole on the side of the case for the network cable.
Install the radiator mounting screw. Place the washer on the back side. Screw on the radiator.
Drill a hole of the appropriate size for the potentiometer, that is, for the handle of the variable resistor. Insert the part into the body and secure with a standard nut.
Place the socket on the body and drill two holes for the wires.
Secure the socket with two M3 nuts. Insert the wires into the holes and tighten the cover with a screw.
Route the wires inside the housing. Solder one of them to the board.
The other is for the core of the network cable, which you first insert into the plastic housing of the regulator.
Insulate the joint with electrical tape.
Connect the free wire of the cord to the board.
Close the housing with the lid and tighten it with screws.

The power regulator is plugged into the network, and the soldering iron is plugged into the regulator socket.

Video: installation of the regulator circuit on a triac and assembly in the housing

On a thyristor

The power regulator can be made using a bt169d thyristor.

Thyristor power regulator

Circuit components:

VS1 - thyristor BT169D;
VD1 - diode 1N4007;
R1 - 220k resistor;
R3 - 1k resistor;
R4 - 30k resistor;
R5 - resistor 470E;
C1 - capacitor 0.1mkF.

Resistors R4 and R5 are voltage dividers. They reduce the signal, since the bt169d thyristor is low-power and very sensitive. The circuit is assembled similarly to a regulator on a triac. Since the thyristor is weak, it will not overheat. Therefore, a cooling radiator is not needed. Such a circuit can be mounted in a small box without a socket and connected in series with the soldering iron wire.

Power regulator in a small housing

Power thyristor circuit

If in the previous circuit you replace the thyristor bt169d with a more powerful ku202n and remove resistor R5, then the output power of the regulator will increase. Such a regulator is assembled with a thyristor-based radiator.

Power thyristor circuit

On a microcontroller with indication

A simple power regulator with light indication can be made on a microcontroller.

Regulator circuit on the ATmega851 microcontroller

Prepare the following components to assemble it:

Using buttons S3 and S4, the power and brightness of the LED will change. The circuit is assembled similarly to the previous ones.

If you want the meter to show the percentage of power output instead of a simple LED, then use a different circuit and appropriate components, including a numeric indicator.

Regulator circuit on PIC16F1823 microcontroller

The circuit can be mounted into a socket.

Regulator on a microcontroller in a socket

Checking and adjusting the thermostat block circuit

Test the unit before connecting it to the instrument.

Take the assembled circuit.
Connect it to the network cable.
Connect a 220 lamp to the board and a triac or thyristor. Depending on your scheme.
Plug the power cord into the socket.
Rotate the variable resistor knob. The lamp must change the degree of incandescence.

The circuit with a microcontroller is checked in the same way. Only the digital indicator will still display the percentage of output power.

To adjust the circuit, change resistors. The greater the resistance, the less power.

It is often necessary to repair or modify various devices using a soldering iron. The performance of these devices depends on the quality of soldering. If you purchased a soldering iron without a power regulator, be sure to install it. With constant overheating, not only electronic components will suffer, but also your soldering iron.

Triac power regulators operate using phase control. They can be used to change the power of various electrical devices operating using alternating voltage.

The devices may include electric incandescent lamps, heating devices, alternating current electric motors, transformer welding machines, and many others. They have a wide range of adjustment, which gives them a wide range of applications, including in everyday life.

Description and principle of operation

The operation of the device is based on regulating the turn-on delay of the triac when the mains voltage crosses zero. The triac is in the closed position at the beginning of the half-cycle. After the voltage of the positive half-wave increases, the capacitor is charged with a phase shift from the mains voltage.

This shift is determined by the resistance values of resistors P1, R1, R2, and the capacitance of capacitor C1. When the threshold value is reached on the capacitor, the triac is turned on. It becomes conductive, allowing voltage to pass through, thereby bridging the circuit with resistors and capacitors. When the half-cycle passes through 0, the triac is turned off.

Then, when the capacitor is charged, it opens again with a negative voltage wave. Such operation of a triac is possible due to its structure. It has five layers of semiconductors with a control electrode. Which gives him the opportunity to swap the anode with the cathode. To put it simply, it can be represented as two thyristors with a back-to-back connection.

Application area

Triac power regulators have found their application not only in everyday life, but also in many industries. In particular, they successfully replace cumbersome relay contact control circuits. They help set optimal currents in automatic welding lines, and in many other industries.

As for the use of these devices in everyday life, its use is very diverse. From regulating the voltage of incandescent lamps to regulating the fan speed. In a nutshell, the range is so diverse that it is not easy to describe.

Types of triac power regulators

Speaking about these devices, it should be noted that they all work on the same principle. Their main difference is the power for which they are designed. The second difference will be the control scheme. Some types of triac may require finer tuning of control signals. Control can be very diverse, from a capacitor and a pair of resistors to a modern microcontroller.

Scheme

Power regulators can use many different designs. The simplest circuit is considered to be the use of a variable resistor, and the most complex is a modern microcontroller. If you use it at home, then you can stick to the simplest one.

It will be enough for most needs. In addition to adjusting the light, the regulator is often used for. Those who like to do electrical engineering at home need to regulate the temperature of the soldering iron.

It is inconvenient to do this using variable resistors, plus there are large losses of electricity. The best solution would be to use a triac regulator.

How to assemble the regulator

For assembly, let's take the simplest circuit diagram. This circuit uses a triac VD2 - VTV 12-600V (600 - 800 V, 12 A), resistors: R1 -680 kOhm, R2 - 47 kOhm, R3 - 1.5 kOhm, R4 - 47 kOhm. Capacitors: C1 – 0.01 mF, C2 – 0.039 mF.

To assemble such a circuit with your own hands, you will need to do certain actions in the correct order:

It is necessary to purchase all the parts from the list presented above.
The second stage will be the development of a printed circuit board. When developing, it should be taken into account that some of the parts will be mounted mounted. And some of the parts will be installed directly into the board.
Creating a board begins with drawing a picture with the location of parts and contact tracks between parts. Then the drawing is transferred to the board blank. When the drawing is transferred to the board, then everything proceeds according to a well-known method. Etching the board, drilling holes for parts, tinning the tracks on the board. Many people use modern computer programs such as Sprint Layout to obtain a board drawing, but if you don’t have them, it’s okay. In this case we have a small diagram. It can be done manually.
When the board is ready, insert the necessary radio components into the prepared holes, shorten the length of the contacts with wire cutters to the required length and begin soldering. To do this, use a soldering iron to warm up the contact point on the board, apply solder to it, when the solder spreads over the surface at the contact point, remove the soldering iron and let the solder cool. In this case, all parts must remain in place and not move. When soldering, safety precautions should be observed. First of all, you need to protect yourself from burns; they can be caused by contact with a soldering iron, or splashes of hot solder or flux. You should have clothing that provides maximum protection to all areas of the body. And to protect your eyes, you need to wear safety glasses. The soldering area should be in a ventilated area, since corrosive gases may appear during operation.
The final stage of assembly will be placing the resulting board into the box. Which box to choose will directly depend on the type of regulator you have. In the case of our scheme, a box the size of a plastic socket will be sufficient. A small number of parts, the largest of which is a variable resistor, take up little space and fit into a small space.
The last step will be to check and configure the device. To do this, you will need a measuring device to monitor the voltage, and a device for the load, in our case a soldering iron. By rotating the regulator knob, you need to examine how smoothly the output voltage changes. If necessary, you can apply marks near the adjustment resistor.

Price

The market is replete with a large number of offers, with different price levels. The price of triac power regulators is primarily influenced by several parameters:

Product power, the more powerful the power, the more expensive your device will be.
The complexity of the control circuit, in the simplest circuits, the main cost is borne by triacs. In complex control circuits where microcontrollers are used, the price may increase due to them. They provide additional features, respectively, at a higher price. So the regulator is on a resistor with a voltage of 220 V, a power of 2500 W. costs 1200 rubles, and on a microcontroller with the same parameters 2450 rubles.
Manufacturer's brand. Sometimes you can pay 50% more for a well-promoted brand.

Now you can find power regulators assembled according to various schemes. Each of them will have its own advantages and disadvantages. Modern regulators are divided into two types, microprocessor and analog. Analog regulators can be classified as economical class systems. They have been known since the times of the USSR, are easy to implement and cheap. Their most important disadvantage is the constant control of the owner or operator.

Let's give a simple example: you need to have a voltage of 170 V at the output. When you set this voltage, the supply voltage was 225 V, and now imagine that the input voltage has changed by 10 V, and the output voltage will change accordingly.

If the output voltage affects the process, problems may arise. In addition to the supply voltage drop, the output voltage can be affected by the parameters of the regulator itself. Since the capacitance of the capacitor changes over time, the variable resistor can be affected by environmental humidity, and it is impossible to achieve stable operation.

Microprocessor-based regulators do not have this problem. They implement feedback that allows you to quickly adjust the control signal.

One of the important aspects of long-term operation will be repair and service. Microprocessor regulators are complex products and require specialized service centers to repair them. Analog regulators are easier to repair. Any radio amateur can do it at home.

You can make the final choice on the triac power regulator after studying the conditions for its operation. When you do not need greater output accuracy, it is reasonable to give preference to an analog device, while saving money. When accuracy is required at the output, do not skimp, buy a microprocessor device.

In this article we will talk about how to make a triac power regulator with your own hands. What is a triac? This is a device built on a semiconductor crystal. It has as many as 5 p-n junctions; current can flow in both the forward and reverse directions. But these elements are not widely used in modern industrial equipment, since they are highly sensitive to electromagnetic interference.

They also cannot operate at high current frequencies; they generate a large amount of heat if they switch large loads. Therefore, IGBT transistors and thyristors are used in industrial equipment. But triacs should not be overlooked either - they are cheap, they are small in size, and most importantly, they have a high service life. Therefore, they can be used where the disadvantages listed above do not play a big role.

How does a triac work?

Today you can find a triac power regulator in any household appliance - grinders, screwdrivers, washing machines and vacuum cleaners. In other words, wherever there is a need for smooth adjustment of engine speed.

The regulator works like an electronic key - it closes and opens at a certain frequency, which is set by the control circuit. When the device is unlocked, half a voltage wave passes through it. Consequently, a small portion of the minimum power is supplied to the load.

Can I do it myself?

Many radio amateurs make their own triac power regulators for various purposes. With its help you can control the heating of the soldering iron tip. But, unfortunately, you can find ready-made devices on the market, but quite rarely.

They have a low cost, but often the devices do not meet the requirements set by consumers. That is why it turns out that it is much easier not to buy a ready-made regulator, but to make it yourself. In this case, you will be able to take into account all the nuances of using the device.

Regulator circuit

Let's look at a simple triac power regulator that can be used with any load. Pulse-phase control, all components are traditional for such designs. The following elements need to be used:

Directly a triac, designed for a voltage of 400 V and a current of 10 A.
Dinistor with an opening threshold of 32 V.
A variable resistor is used to regulate power.

The current that flows through the variable resistor and resistance charges the capacitor with each half-wave. As soon as the capacitor accumulates charge and the voltage between its plates is 32 V, the dinistor will open. In this case, the capacitor is discharged through it and the resistance to the control input of the triac. The latter opens to allow current to pass to the load.

To change the duration of the pulses, you need to select a variable resistor and the threshold voltage of the dinistor (but this is a constant value). Therefore, you will have to “play” with the resistance of the variable resistor. In the load, the power is resisted by a variable resistor. It is not necessary to use diodes and a constant resistor; the chain is designed to ensure accurate and smooth power control.

How the device works

The current that flows through the dinistor is limited by a constant resistor. It is with its help that the pulse length is adjusted. Using a fuse, the circuit is protected from short circuit. It should be noted that the dinistor in each half-wave opens to the same angle.

Therefore, rectification of the flowing current does not occur; even an inductive load can be connected to the output. Therefore, a triac power regulator can also be used for a transformer. In order to select triacs, you need to take into account that for a load of 200 W it is necessary that the current be equal to 1 A.

The circuit uses the following elements:

Dinistor type DB3.
Triacs such as VT136-600, TS106-10-4 and similar ones with a current rating of up to 12 A.
Germanium semiconductor diodes - 1N4007.
Electrolytic capacitor for voltage more than 250 V, capacity 0.47 µF.
Variable resistor 100 kOhm, constant resistor - from 270 Ohm to 1.6 kOhm (selected experimentally).

Features of the regulator circuit

This scheme is the most common, but you can also find small variations. For example, sometimes a diode bridge is installed instead of a dinistor. In some circuits there is a chain of capacitance and resistance to suppress interference. There are also more modern designs that use a microcontroller control circuit. When using this circuit, you get precise control of the current and voltage in the load, but it is more difficult to implement.

Preparatory work

In order to assemble a triac power regulator for an electric motor, you just need to follow this sequence:

First you need to determine the characteristics of the device that will be connected to the regulator. The characteristics include: the number of phases (either 3 or 1), the need for precise power adjustment, voltage and current.
Now you need to select a specific device type - digital or analog. After this, you can select components based on load power. In principle, special software can be used for modeling.
Calculate the heat dissipation. To do this, multiply two parameters - the rated current (in Amperes) and the voltage drop across the triac (in Volts). All this data can be found among the characteristics of the element. As a result, you will get the power dissipation expressed in Watts. Based on this value, you need to select a radiator and cooler (if necessary).
Purchase all the necessary items or prepare them if you have them.

Now you can proceed directly to assembling the device.

Regulator assembly

Before assembling a triac power regulator according to the circuit, you need to perform a number of actions:

Lay out the tracks on the board and prepare the sites on which you want to install the elements. Provide in advance places for mounting the triac and radiator.
Install all elements on the board and solder them. If you do not have the opportunity to make a printed circuit board, you can use surface mounting. The wires that connect all elements should be as short as possible.
Pay attention to whether the polarity is correct when connecting the triac and diodes. If there are no markings, test the elements with a multimeter.
Check the circuit using a multimeter in resistance mode.
Attach the triac to the radiator; it is advisable to use thermal paste for better surface contact.
The entire circuit can be installed in a plastic case.
Set the variable resistor knob to the far left position and turn on the device.
Measure the voltage value at the device output. If you rotate the resistor knob, the voltage should increase smoothly.

As you can see, a self-made triac power regulator is a useful design that can be used in everyday life with almost no restrictions. Repair of this device is cheap, since the cost is quite low.