High power triacs. Let's figure out how our thyristor power regulator works specifically

16.06.2019 Interesting

Due to the problem with electricity, people are increasingly buying power regulators. It is no secret that sudden changes, as well as excessively low or high voltage, have a detrimental effect on household appliances. In order to prevent damage to property, it is necessary to use a voltage regulator that will protect electronic devices from short circuits and various negative factors.

Regulator types

Nowadays on the market you can see a huge number of different regulators for both the whole house and low-power individual household appliances. There are transistor voltage regulators, thyristor, mechanical (voltage regulation is carried out using a mechanical slider with a graphite rod at the end). But the most common is the triac voltage regulator. The basis of this device is triacs, which allow you to sharply react to voltage surges and smooth them out.

A triac is an element that contains five pn junctions. This radio element has the ability to pass current both in the forward direction and in the opposite direction.

These components can be observed in various household appliances, from hair dryers and table lamps to soldering irons, where smooth adjustment is required.

The principle of operation of a triac is quite simple. This is a kind of electronic key, which then closes the doors, then opens them at a given frequency. When the P-N junction of the triac opens, it passes a small part of the half-wave and the consumer receives only a part of the nominal power. That is, the more the P-N junction opens, the more power the consumer receives.

The advantages of this element include:

In connection with the above advantages, triacs and regulators based on them are used quite often.

This circuit is fairly easy to assemble and doesn't require a lot of parts. Such a regulator can be used to adjust not only the temperature of the soldering iron, but also ordinary incandescent and LED lamps. You can connect various drills, grinders, vacuum cleaners, grinders to this scheme, which initially went without a smooth speed adjustment.

Such a 220v voltage regulator with your own hands can be assembled from the following parts:

R1 is a 20 kOhm resistor with a power of 0.25 W.
R2 is a variable resistor of 400-500 kOhm.
R3 - 3 kOhm, 0.25 W.
R4-300 Ohm, 0.5W.
C1 C2 - non-polar capacitors 0.05 MKF.
C3 - 0.1 Mcf, 400 V.
DB3 is a dinistor.
BT139-600 - the triac must be selected depending on the load that will be connected. The device assembled according to this scheme can regulate the current of 18A.
It is advisable to apply a radiator to the triac, since the element heats up quite a lot.

The circuit has been tested and works quite stably under different types of load..

There is another universal power regulator circuit.

An alternating voltage of 220 V is supplied to the input of the circuit, and 220 V DC is already at the output. This scheme already has more parts in its arsenal, and accordingly the complexity of the assembly increases. Any consumer (direct current) can be connected to the circuit output. In most houses and apartments, people try to install energy-saving lamps. Not every regulator can cope with smooth regulation of such a lamp, for example, it is undesirable to use a thyristor regulator. This circuit allows you to seamlessly connect these lamps and make a kind of nightlights out of them.

The peculiarity of the circuit is that when the lamps are turned on to a minimum, all household appliances must be disconnected from the network. After that, a compensator will work in the counter, and the disc will slowly stop, and the light will continue to burn. This is an opportunity to assemble a triac power regulator with your own hands. The denominations of the parts required for assembly can be seen in the diagram.

Another interesting circuit that allows you to connect a load of up to 5A and a power of up to 1000W.

The regulator is assembled on the basis of the BT06-600 triac. The principle of operation of this circuit is to open the junction of the triac. The more the element is open, the more power is supplied to the load. And also in the circuit there is an LED that will let you know if the device is working or not. List of parts that will be needed to assemble the device:

R1 is a 3.9 kΩ resistor and R2 is 500 kΩ, a kind of voltage divider that serves to charge the capacitor C1.
capacitor C1 - 0.22 μF.
dinistor D1 - 1N4148.
LED D2, serves to indicate the operation of the device.
dinistors D3 - DB4 U1 - BT06-600.
terminals for load connection P1, P2.
resistor R3 - 22kOhm and power 2W
capacitor C2 - 0.22μF is designed for a voltage of at least 400 V.

Triacs and thyristors are successfully used as starters. Sometimes it is necessary to start very powerful heating elements, control the switching on of powerful welding equipment, where the current strength reaches 300-400 A. Mechanical switching on and off with the help of contactors is inferior to the triac starter due to the rapid wear of the contactors, moreover, during mechanical switching on, an arc arises, which also detrimental to contactors. Therefore, it would be advisable to use triacs for these purposes. Here is one of the schemes.

All ratings and parts list are shown in Fig. 4. The advantage of this circuit is complete galvanic isolation from the mains, which will ensure safety in case of damage.

Often on the farm it is necessary to carry out welding work. If there is a ready-made inverter welding machine, then welding does not present any particular difficulties, since the machine has a current adjustment. Most people do not have such a welding one and have to use a conventional transformer welding one, in which the current is adjusted by changing the resistance, which is rather inconvenient.

Those who have tried using a triac as a regulator will be disappointed. It will not adjust the power. This is due to a phase shift, because of which, during a short pulse, the semiconductor switch does not have time to go into the "open" mode.

But there is a way out of this situation. A pulse of the same type should be applied to the control electrode, or a constant signal should be applied to the control electrode (control electrode) until there is a pass through zero. The regulator circuit looks like this:

Of course, the circuit is quite difficult to assemble, but this option will solve all problems with regulation. Now you will not need to use a bulky resistance, moreover, very smooth adjustment will not work. In the case of a triac, a fairly smooth adjustment is possible.

If there are constant voltage drops, as well as undervoltage or overvoltage, it is recommended to purchase a triac regulator or, if possible, make a regulator with your own hands. The regulator will protect household appliances and prevent damage to them.

The triac power regulator is designed to adjust the power of heating and lighting devices whose power does not exceed 1000 W.

Specifications:
Working voltage; 160-300V
Power adjustment range 10-90%
Load current: up to 5 A

The device consists of a triac and a timing chain. The principle of power regulation is to change the duration of the open state of the triac (Figure 1). The longer the triac is open, the more power is delivered to the load. And since the triac turns off at the moment when the current flowing through the triac is zero, we will set the duration of the triac opening within half the period. At the beginning of the positive half-cycle, the triac is closed. As the mains voltage increases, the capacitor C1 is charged through the divider R1, R2. The charge of the capacitor continues until the voltage across it reaches the "breakdown" threshold of the dinistor (about 32 V). The dynistor will close the circuit Dl, Cl, D3 and open the triac U1. The triac remains open until the end of the half cycle. The charging time of the capacitor is set by the parameters of the chain R1, R2, C1. Resistor R2 sets the charging time of the capacitor, and, accordingly, the moment of opening the dinistor and triac. Those. this resistor adjusts the power. Under the action of a negative half-wave, the principle of operation is similar. The LED indicator indicates the operating mode of the power regulator.

Used radioelements:
R1 - 3.9 ... 10K
R2 - 500K
C1 - 0.22μF
D1 - 1N4148
D2 - LED
D3 - DB4
U1 - BT06-600
P1, P2 terminals
R3 - 22K 2W
C2 - 0.22μF 400V

Correctly assembled circuit does not require adjustment.
When using a load with a power of more than 300 W, the triac must be installed on a radiator with a surface area of at least 20 cm 2
A handle made of insulated material must be installed on the variable resistor.

When the circuit is supplemented with only two elements (marked in red in the diagram), it becomes possible to control an inductive load. Those. you can connect a transformer to the output of the triac power regulator.

ATTENTION! The device is not galvanically isolated from the mains! It is forbidden to touch the elements of the included circuit!

The article describes how a thyristor power regulator works, the circuit of which will be presented below.

In everyday life, it is very often necessary to regulate the power of household appliances, for example, an electric stove, a soldering iron, boilers and heating elements, in transport - engine speed, etc. The simplest radio amateur design comes to the rescue - a power regulator on a thyristor. It is not difficult to assemble such a device, it can become the very first home-made device that will perform the function of adjusting the temperature of the soldering iron tip of a novice radio amateur. It should be noted that ready-made soldering stations with temperature control and other pleasant functions are much more expensive than a simple soldering iron. The minimum set of parts allows you to assemble a simple wall-mounted thyristor power regulator.

For your information, surface mounting is a way of assembling electronic components without using a printed circuit board, and with good skill, it allows you to quickly assemble electronic devices of average complexity.

You can also order a thyristor regulator, and for those who want to figure it out on their own, a diagram will be presented below and the principle of operation will be explained.

Incidentally, this is a single-phase thyristor power regulator. Such a device can be used to control power or the number of revolutions. However, first you need to understand the principle of operation of the thyristor, because this will allow us to understand for what load it is better to use such a regulator.

How does a thyristor work?

A thyristor is a controlled semiconductor device capable of conducting current in one direction. The word "controlled" is used for a reason, because with its help, unlike a diode, which also conducts current to only one pole, it is possible to choose the moment when the thyristor begins to conduct current. The thyristor has three outputs:

Anode.
Cathode.
Control electrode.

In order for the current to start flowing through the thyristor, the following conditions must be met: the part must be in a live circuit, and a short pulse must be applied to the control electrode. Unlike a transistor, thyristor control does not require holding the control signal. This is not the end of the nuances: the thyristor can be closed by only interrupting the current in the circuit, or by forming a reverse anode-cathode voltage. This means that the use of a thyristor in DC circuits is very specific and often unreasonable, but in AC circuits, for example, in such a device as a thyristor power regulator, the circuit is built in such a way that a condition for closing is provided. Each of the half-waves will close the corresponding thyristor.

You, most likely, do not understand everything? Do not despair - the process of the finished device will be described in detail below.

Scope of thyristor regulators

In what circuits is it effective to use a thyristor power regulator? The circuit allows you to perfectly regulate the power of heating devices, that is, to affect the active load. When working with a highly inductive load, the thyristors may simply not close, which can lead to the failure of the regulator.

Can you motor?

I think many of the readers have seen or used drills, angle grinders, which are popularly called "grinders", and other power tools. You may have noticed that the number of turns depends on the depth of pressing the trigger of the device. It is in this element that such a thyristor power regulator is built (the diagram of which is shown below), with the help of which the number of revolutions is changed.

Note! The thyristor regulator cannot change the speed of asynchronous motors. Thus, the voltage is regulated on brushed motors equipped with a brush assembly.

Scheme of one and two thyristors

A typical circuit for assembling a thyristor power regulator with your own hands is shown in the figure below.

The output voltage of this circuit is from 15 to 215 volts, in the case of using these thyristors installed on heat sinks, the power is about 1 kW. By the way, a switch with a dimmer is made according to a similar scheme.

If you do not need full voltage regulation and you only need to get 110 to 220 volts at the output, use this diagram, which shows a half-wave power regulator on a thyristor.

How it works?

The information described below is valid for most circuits. The letter designations will be taken in accordance with the first circuit of the thyristor regulator

The thyristor power regulator, the principle of operation of which is based on phase control of the voltage value, also changes the power. This principle is that, under normal conditions, the load is acted upon by an alternating voltage of the household network, which changes according to a sinusoidal law. Above, in the description, it was said that each thyristor works in one direction, that is, it controls its half-wave from a sinusoid. What does it mean?

If, with the help of a thyristor, the load is periodically connected at a strictly defined moment, the value of the effective voltage will be lower, since part of the voltage (the effective value that "gets" to the load) will be less than the mains voltage. This phenomenon is illustrated in the graph.

The shaded area is the area of stress that is under load. The letter "a" on the horizontal axis indicates the moment when the thyristor opens. When the positive half-wave ends and a period with a negative half-wave begins, one of the thyristors closes, and at the same moment the second thyristor opens.

Let's figure out how our thyristor power regulator works specifically

The first scheme

Let us stipulate in advance that instead of the words "positive" and "negative", "first" and "second" (half-wave) will be used.

So, when the first half-wave begins to act on our circuit, the capacities C1 and C2 begin to charge. Their charge rate is limited by potentiometer R5. this element is variable, and with its help the output voltage is set. When the voltage required to open the dynistor VS3 appears on the capacitor C1, the dynistor opens, a current flows through it, with the help of which the thyristor VS1 will be opened. The moment of breakdown of the dinistor is point "a" on the chart presented in the previous section of the article. When the voltage value crosses zero and the circuit is under the second half-wave, the thyristor VS1 closes, and the process is repeated again, only for the second dynistor, thyristor and capacitor. Resistors R3 and R3 are used for control, and R1 and R2 are used for thermal stabilization of the circuit.

The principle of operation of the second circuit is similar, but it controls only one of the half-waves of the alternating voltage. Now, knowing the principle of operation and the circuit, you can assemble or repair a thyristor power regulator with your own hands.

The use of the regulator in everyday life and safety

It must be said that this circuit does not provide galvanic isolation from the network, therefore there is a danger of electric shock. This means that you should not touch the regulator elements with your hands. An insulated enclosure must be used. The design of your device should be designed so that, if possible, you can hide it in an adjustable device, find free space in the case. If the adjustable device is stationary, then in general it makes sense to connect it through a switch with a dimmer. Such a solution will partially protect against electric shock, eliminate the need to search for a suitable case, has an attractive appearance and is manufactured using an industrial method.

Today I will tell you about a very useful scheme that will come in handy both in the laboratory and on the farm. The device in question is called a triac power regulator. The regulator can be used to smoothly adjust the brightness of the lighting, the temperature of the soldering iron, the speed of the electric motor (alternating current). My version of using the regulator is more interesting, I smoothly regulate the heating temperature of a 1 kW heating element in a moonshine still. Yes, yes, I am engaged in this noble cause.

The circuit has a minimum of elements and starts immediately. The load power for a triac regulator is determined by the triac current. The BTA12-600 triac is designed for a current of 12 Amperes and a voltage of 600 Volts. The triac must be chosen with a current margin, I chose a two-fold margin. For example, a BTA12-600 triac with optimal cooling can pass a current of 8 Amperes through itself in normal mode. If you need a more powerful regulator, use a BTA16-600 or BTA24-600 triac.

The operating temperature of the triac crystal is from -40 to +125 degrees Celsius. Good cooling needs to be done. I have a load of 1kW, respectively, a load current of about 5A, a radiator with an area of 200cm square. heats up from 85 to 90 degrees Celsius during long-term operation (up to 6 hours). I plan to increase the working area of the radiator to improve the reliability of the device.

The triac has a control terminal and two terminals through which the load current flows. These two conclusions can be swapped, nothing terrible will happen.

For safety (so that the current does not click), the triac must be installed on the radiator through a dielectric gasket (polymer or mica) and a dielectric bushing.

Components.

Resistor 4.7kOhm with a power of 0.25W. Dynistor marked DB3, has no polarity, solder with either side. A 100nF 400V film capacitor has no polarity.

LED of any color, diameter 3mm, reverse voltage 5V, current 25mA. In short, any LED 3mm. The LED indicates the load, do not be alarmed if it does not light up when you turn it on for the first time (naturally without load).

The first start-up must be done for a short time without load. If everything is fine, no elements are heating up, nothing clicked, then we turn it on without load for 15 seconds. Next, we catch a lamp with a voltage of 220V and a power of 60-200W, turn the handle of the variable resistor and enjoy the work.

For protection, I installed a 12A fuse in the break in the mains wire (220V).

The power regulator we assembled on the BTA12-600 triac can be used to adjust the temperature of the soldering iron (by adjusting the power), thereby obtaining a soldering station for your workshop.

Such a simple, but at the same time very effective regulator can be assembled by almost everyone who can hold a soldering iron in their hands and read the circuits even slightly. Well, this site will help you make your wish come true. The presented regulator regulates power very smoothly without surges and dips.

Simple triac regulator circuit

Such a regulator can be used in the regulation of lighting with incandescent lamps, but also with LED lamps, if you buy dimmable ones. It is easy to adjust the temperature of the soldering iron. You can steplessly regulate the heating, change the speed of rotation of electric motors with a phase rotor, and there are many more where there is a place for such a useful thing. If you have an old electric drill that has no speed control, then using this regulator, you will improve such a useful thing.
The article, with the help of photos, descriptions and the attached video, describes in great detail the entire manufacturing process, from collecting parts to testing the finished product.

I say right away that if you are not on friendly terms with your neighbors, then the C3 - R4 chain may not be assembled. (Joke) It serves to protect against radio interference.
All parts can be bought in China on Aliexpress. Prices are from two to ten times less than in our stores.
To make this device you will need:

R1 - a resistor of about 20 KOhm, with a power of 0.25 W;
R2 is a potentiometer of about 500 Kohm, from 300 Kohm to 1 Megohm is possible, but better than 470 Kohm;
R3 - resistor of about 3 Kom, 0.25 W;
R4- resistor 200-300 Ohm, 0.5 W;
C1 and C2 - capacitors 0.05 MKF, 400 V;
C3 - 0.1 MKF, 400 V;
DB3 - dinistor, found in every energy-saving lamp;
BT139-600, regulates the current 18 A or BT138-800, regulates the current 12 A - triacs, but you can take any others, depending on what kind of load needs to be regulated. Dinistor is also called diac, triac is called triac.
The cooling radiator is selected on the basis of the planned control power, but the more the better. Without a radiator, a maximum of 300 watts can be adjusted.
Any terminal blocks can be supplied;
Use the breadboard as you wish, as long as everything is included.
Well, without a device, as without hands. But it is better to use our solder. Although it is more expensive, it is much better. I have not seen good Chinese solder.

Getting started assembling the regulator

First, you need to think over the arrangement of the parts so as to put as few jumpers as possible and solder less, then we very carefully check the compliance with the diagram, and then we solder all the connections.