Thyristor power regulator: circuit, operating principle and application. Power regulation Thyristor power regulator for inductive circuit

A semiconductor device that has 5 p-n junctions and is capable of passing current in the forward and reverse directions is called a triac.

Due to the inability to operate at high frequencies of alternating current, high sensitivity to electromagnetic interference and significant heat generation when switching large loads, they are currently not widely used in high-power industrial installations.

There they are successfully replaced by circuits based on thyristors and IGBT transistors. But the compact dimensions of the device and its durability, combined with the low cost and simplicity of the control circuit, allowed them to be used in areas where the above disadvantages are not significant.

Today, triac circuits can be found in many household appliances from hair dryers to vacuum cleaners, hand-held power tools and electric heating devices - where smooth power adjustment is required.

Principle of operation

The power regulator on a triac works like an electronic key, periodically opening and closing at a frequency specified by the control circuit.

When unlocked, the triac passes part of the half-wave of the mains voltage, which means the consumer receives only part of the rated power. Do it yourself

Today, the range of triac regulators on sale is not very large.

And, although the prices for such devices are low, they often do not meet consumer requirements. For this reason, we will consider several basic circuits of regulators, their purpose and the element base used. Device diagram

The simplest version of the circuit, designed to work with any load.

• Traditional electronic components are used, the control principle is phase-pulse.
• Main components:
• triac VD4, 10 A, 400 V;

dinistor VD3, opening threshold 32 V; potentiometer R2.

The opening duration is regulated by selecting the threshold voltage VD3 (constant value) and resistance R2. The power in the load is directly proportional to the resistance value of potentiometer R2.

An additional circuit of diodes VD1 and VD2 and resistance R1 is optional and serves to ensure smooth and accurate adjustment of the output power.

The current flowing through VD3 is limited by resistor R4. This achieves the pulse duration required to open VD4. Fuse Pr.1 protects the circuit from short circuit currents.

A distinctive feature of the circuit is that the dinistor opens at the same angle in each half-wave of the mains voltage. As a result, the current does not rectify, and it becomes possible to connect an inductive load, for example a transformer.

Triacs should be selected according to the load size, based on the calculation of 1 A = 200 W.

• Elements used:
• Dinistor DB3;
• Triac TS106-10-4, VT136-600 or others, the required current rating is 4-12A.
• Diodes VD1, VD2 type 1N4007;
• Resistances R1100 kOhm, R3 1 kOhm, R4 270 Ohm, R5 1.6 kOhm, potentiometer R2 100 kOhm;

C1 0.47 µF (operating voltage from 250 V). Note that the scheme is the most common, with minor variations.

For example, a dinistor can be replaced with a diode bridge, or an interference-suppressing RC circuit can be installed in parallel with the triac. A more modern circuit is one that controls the triac from a microcontroller - PIC, AVR or others.

Triac power regulator circuit

Assembly

1. The power regulator must be assembled in the following sequence: Determine the parameters of the device on which the device being developed will work.
2. Parameters include: number of phases (1 or 3), the need for precise adjustment of output power, input voltage in volts and rated current in amperes. Select the type of device (analog or digital), select elements according to load power.
3. Calculate the heat dissipation using the following formula: voltage drop across the triac (about 2 V) multiplied by the rated current in amperes.
4. The exact values ​​of the voltage drop in the open state and the rated current flow are indicated in the characteristics of the triac. We get the power dissipation in watts. Select a radiator according to the calculated power. Purchase the necessary electronic components
5. , radiator and printed circuit board. Lay out contact tracks on the board and prepare sites for installing elements.
6. Provide mounting on the board for a triac and radiator. Install the elements onto the board using soldering.
7. If it is not possible to prepare a printed circuit board, then you can use surface mounting to connect the components using short wires. When assembling, pay special attention to the polarity of connecting the diodes and triac. If there are no pin markings on them, then there are “arcs”. Check the assembled circuit with a multimeter in resistance mode.
8. The resulting product must correspond to the original design. Securely attach the triac to the radiator.
9. Don’t forget to lay an insulating heat transfer gasket between the triac and the radiator. The fastening screw is securely insulated. Place the assembled circuit
10. in a plastic case. Remember that at the terminals of the elements
11. Dangerous voltage is present. Turn the potentiometer to minimum and perform a test run.
12. Measure the voltage at the output of the regulator with a multimeter. Smoothly turn the potentiometer knob to monitor the change in output voltage. If the result is satisfactory, then you can connect the load to the output of the regulator.

Triac power radiator

Power adjustment

• The power control is controlled by a potentiometer, through which the capacitor and the capacitor discharge circuit are charged. If the output power parameters are unsatisfactory, you should select the resistance value in the discharge circuit and, if the power adjustment range is small, the potentiometer value.
• extend lamp life, adjust lighting or soldering iron temperature A simple and inexpensive regulator using triacs will help.
• select the circuit type and component parameters according to the planned load.
• work it out carefully circuit solutions.
• be careful when assembling the circuit, observe the polarity of semiconductor components.

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

In everyday life, very often there is a need to regulate the power of household appliances, such as electric stoves, soldering irons, boilers and heating elements, in transport - engine speed, etc. The simplest amateur radio design comes to the rescue - a power regulator on a thyristor. Assembling such a device will not be difficult; 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 is worth noting that ready-made soldering stations with temperature control and other nice functions are an order of magnitude more expensive than a simple soldering iron. A minimal set of parts allows you to assemble a simple thyristor power regulator for wall mounting.

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

By the way, this is a single-phase thyristor power regulator. Such a device can be used to control power or speed. However, first we need to understand this 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” was used for a reason, because with its help, unlike a diode, which also conducts current only to one pole, you can select the moment when the thyristor begins to conduct current. The thyristor has three outputs:

• Anode.
• Cathode.
• Control electrode.

In order for current to begin flowing through the thyristor, the following conditions must be met: the part must be in a circuit that is energized, and a short-term pulse must be applied to the control electrode. Unlike a transistor, controlling a thyristor does not require holding the control signal. The nuances do not end there: the thyristor can be closed only by interrupting the current in the circuit, or by generating a reverse anode-cathode voltage. This means that the use of a thyristor in DC circuits is very specific and often unwise, but in AC circuits, for example in a device such as a thyristor power regulator, the circuit is constructed in such a way that a condition for closing is ensured. Each half-wave will close the corresponding thyristor.

Most likely, you don’t understand everything? Do not despair - below the process of operation of the finished device will be described in detail.

Scope of application 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, influence the active load. When working with a highly inductive load, the thyristors may simply not close, which can lead to failure of the regulator.

Is it possible to have an engine?

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 revolutions depends on the depth of pressing the trigger button of the device. It is in this element that a thyristor power regulator is built in (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 commutator 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 the indicated thyristors installed on heat sinks, the power is about 1 kW. By the way, the switch with the light brightness control is made according to a similar scheme.

If you don't need to fully regulate the voltage and just want an output of 110 to 220 volts, use this diagram, which shows a half-wave thyristor power regulator.

How it works?

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

A thyristor power regulator, the operating principle of which is based on phase control of the voltage value, also changes the power. This principle lies in the fact that under normal conditions the load is affected by the alternating voltage of the household network, changing according to a sinusoidal law. Above, when describing the operating principle of a thyristor, it was said that each thyristor operates in one direction, that is, it controls its own half-wave from a sine wave. What does it mean?

If you periodically connect a load using a thyristor at a strictly defined moment, the value of the effective voltage will be lower, since part of the voltage (the effective value that “falls” on 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 opening moment of the thyristor. When the positive half-wave ends and the period with the negative half-wave begins, one of the thyristors closes, and at the same moment the second thyristor opens.

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

Scheme one

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, capacitors C1 and C2 begin to charge. Their charging speed is limited by potentiometer R5. this element is variable, and with its help the output voltage is set. When the voltage necessary to open dinistor VS3 appears on capacitor C1, the dinistor opens and current flows through it, with the help of which thyristor VS1 will be opened. The moment of breakdown of the dinistor is point “a” on the graph presented in the previous section of the article. When the voltage value passes through zero and the circuit is under the second half-wave, the thyristor VS1 closes, and the process is repeated again, only for the second dinistor, 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 alternating voltage. Now, knowing the principle of operation and the circuit, you can assemble or repair a thyristor power regulator with your own hands.

Using the regulator in everyday life and safety precautions

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

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 through 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.

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:

1. Install a tachometer that measures the speed. This option allows for precise adjustment, but this increases the cost of implementing the solution.
2. 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:

1. Supplying a series of similar pulses to the control electrode.
2. 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.

A selection of circuits and a description of the operation of a power regulator using triacs and more. Triac power regulator circuits are well suited for extending the life of incandescent lamps and for adjusting their brightness. Or for powering non-standard equipment, for example, 110 volts.

The figure shows a circuit of a triac power regulator, which can be changed by changing the total number of network half-cycles passed by the triac over a certain time interval. The elements of the DD1.1.DD1.3 microcircuit are made with an oscillation period of about 15-25 network half-cycles.

The duty cycle of the pulses is regulated by resistor R3. Transistor VT1 together with diodes VD5-VD8 is designed to bind the moment the triac is turned on during the transition of the mains voltage through zero. Basically, this transistor is open, respectively, a “1” is sent to the input DD1.4 and transistor VT2 with triac VS1 are closed. At the moment of crossing zero, transistor VT1 closes and opens almost immediately. In this case, if the output DD1.3 was 1, then the state of the elements DD1.1.DD1.6 will not change, and if the output DD1.3 was “zero”, then the elements DD1.4.DD1.6 will generate a short pulse, which will be amplified by transistor VT2 and open the triac.

As long as there is a logical zero at the output of the generator, the process will proceed cyclically after each transition of the mains voltage through the zero point.

The basis of the circuit is a foreign triac mac97a8, which allows you to switch high-power connected loads, and to regulate it I used an old Soviet variable resistor, and used a regular LED as an indication.

The triac power regulator uses the principle of phase control. The operation of the power regulator circuit is based on changing the moment the triac is turned on relative to the transition of the mains voltage through zero. At the initial moment of the positive half-cycle, the triac is in the closed state. As the mains voltage increases, capacitor C1 is charged through a divider.

The increasing voltage on the capacitor is shifted in phase from the mains voltage by an amount depending on the total resistance of both resistors and the capacitance of the capacitor. The capacitor is charged until the voltage across it reaches the “breakdown” level of the dinistor, approximately 32 V.

At the moment the dinistor opens, the triac will also open, and a current will flow through the load connected to the output, depending on the total resistance of the open triac and the load. The triac will be open until the end of the half-cycle. With resistor VR1 we set the opening voltage of the dinistor and triac, thereby regulating the power. At the time of the negative half-cycle, the circuit operation algorithm is similar.

Option of the circuit with minor modifications for 3.5 kW

The controller circuit is simple, the load power at the output of the device is 3.5 kW. With this homemade amateur radio you can adjust lighting, heating elements and much more. The only significant drawback of this circuit is that you cannot connect an inductive load to it under any circumstances, because the triac will burn out!

Radio components used in the design: Triac T1 - BTB16-600BW or similar (KU 208 or VTA, VT). Dinistor T - type DB3 or DB4. Capacitor 0.1 µF ceramic.

Resistance R2 510 Ohm limits the maximum volts on the capacitor to 0.1 μF; if you put the regulator slider in the 0 Ohm position, the circuit resistance will be about 510 Ohms. The capacitance is charged through resistors R2 510 Ohm and variable resistance R1 420 kOhm, after U on the capacitor reaches the opening level of dinistor DB3, the latter will generate a pulse that unlocks the triac, after which, with further passage of the sinusoid, the triac is locked. The opening and closing frequency of T1 depends on the level of U on the 0.1 μF capacitor, which depends on the resistance of the variable resistor. That is, by interrupting the current (at a high frequency) the circuit thereby regulates the output power.

With each positive half-wave of the input alternating voltage, capacitance C1 is charged through a chain of resistors R3, R4, when the voltage on capacitor C1 becomes equal to the opening voltage of dinistor VD7, its breakdown will occur and the capacitance will be discharged through the diode bridge VD1-VD4, as well as resistance R1 and control electrode VS1. To open the triac, an electrical chain of diodes VD5, VD6, capacitor C2 and resistance R5 is used.

It is necessary to select the value of resistor R2 so that at both half-waves of the mains voltage, the regulator triac operates reliably, and it is also necessary to select the values ​​of resistances R3 and R4 so that when the variable resistance knob R4 is rotated, the voltage on the load smoothly changes from minimum to maximum values. Instead of the TC 2-80 triac, you can use TC2-50 or TC2-25, although there will be a slight loss in the permissible power in the load.

KU208G, TS106-10-4, TS 112-10-4 and their analogs were used as a triac. At the moment when the triac is closed, capacitor C1 is charged through the connected load and resistors R1 and R2. The charging speed is changed by resistor R2, resistor R1 is designed to limit the maximum value of the charge current

When the threshold voltage value is reached on the capacitor plates, the switch opens, capacitor C1 is quickly discharged to the control electrode and switches the triac from the closed state to the open state; in the open state, the triac bypasses the circuit R1, R2, C1. At the moment the mains voltage passes through zero, the triac closes, then capacitor C1 is charged again, but with a negative voltage.

Capacitor C1 from 0.1...1.0 µF. Resistor R2 1.0...0.1 MOhm. The triac is switched on by a positive current pulse to the control electrode with a positive voltage at the conventional anode terminal and by a negative current pulse to the control electrode with a negative voltage at the conventional cathode. Thus, the key element for the regulator must be bidirectional. You can use a bidirectional dinistor as a key.

Diodes D5-D6 are used to protect the thyristor from possible breakdown by reverse voltage. The transistor operates in avalanche breakdown mode. Its breakdown voltage is about 18-25 volts. If you don’t find P416B, then you can try to find a replacement for it.

The pulse transformer is wound on a ferrite ring with a diameter of 15 mm, grade N2000. The thyristor can be replaced with KU201

The circuit of this power regulator is similar to the circuits described above, only the interference suppression circuit C2, R3 is introduced, and the switch SW makes it possible to break the charging circuit of the control capacitor, which leads to instant locking of the triac and disconnecting the load.

C1, C2 - 0.1 MKF, R1-4k7, R2-2 mOhm, R3-220 Ohm, VR1-500 kOhm, DB3 - dinistor, BTA26-600B - triac, 1N4148/16 V - diode, any LED.

The regulator is used to regulate load power in circuits up to 2000 W, incandescent lamps, heating devices, soldering iron, asynchronous motors, car charger, and if you replace the triac with a more powerful one, it can be used in the current regulation circuit in welding transformers.

The principle of operation of this power regulator circuit is that the load receives a half-cycle of the mains voltage after a selected number of skipped half-cycles.

The diode bridge rectifies alternating voltage. Resistor R1 and zener diode VD2, together with the filter capacitor, form a 10 V power source to power the K561IE8 microcircuit and the KT315 transistor. The rectified positive half-cycles of the voltage passing through capacitor C1 are stabilized by the zener diode VD3 at a level of 10 V. Thus, pulses with a frequency of 100 Hz follow to the counting input C of the K561IE8 counter. If switch SA1 is connected to output 2, then a logical one level will be constantly present at the base of the transistor. Because the microcircuit reset pulse is very short and the counter manages to restart from the same pulse.

Pin 3 will be set to a logical one level. The thyristor will be open. All power will be released at the load. In all subsequent positions of SA1 at pin 3 of the counter, one pulse will pass through 2-9 pulses.

The K561IE8 chip is a decimal counter with a positional decoder at the output, so the logical one level will be periodic at all outputs. However, if the switch is installed on output 5 (pin 1), then counting will only occur up to 5. When the pulse passes through output 5, the microcircuit will be reset to zero. Counting will begin from zero, and a logical one level will appear at pin 3 for the duration of one half-cycle. During this time, the transistor and thyristor open, one half-cycle passes to the load. To make it clearer, I present vector diagrams of the circuit operation.

If you need to reduce the load power, you can add another counter chip by connecting pin 12 of the previous chip to pin 14 of the next one. By installing another switch, you can adjust the power up to 99 missed pulses. Those. you can get about a hundredth of the total power.

The KR1182PM1 microcircuit has two thyristors and a control unit for them. The maximum input voltage of the KR1182PM1 microcircuit is about 270 Volts, and the maximum load can reach 150 Watts without the use of an external triac and up to 2000 W with the use, and also taking into account the fact that the triac will be installed on the radiator.

To reduce the level of external interference, capacitor C1 and inductor L1 are used, and capacitance C4 is required for smooth switching on of the load. The adjustment is carried out using resistance R3.

A selection of fairly simple regulator circuits for a soldering iron will make life easier for a radio amateur.

Combination consists in combining the convenience of using a digital regulator and the flexibility of adjusting a simple one.

The considered power regulator circuit works on the principle of changing the number of periods of the input alternating voltage going to the load. This means that the device cannot be used to adjust the brightness of incandescent lamps due to visible blinking. The circuit makes it possible to regulate power within eight preset values.

There are a huge number of classic thyristor and triac regulator circuits, but this regulator is made on a modern element base and, in addition, was phase-based, i.e. does not transmit the entire half-wave of the mains voltage, but only some part of it, thereby limiting the power, since the triac opens only at the required phase angle.

Transformers, like electric motors, have a steel core. In it, the upper and lower half-wave voltage must be symmetrical. It is for this purpose that regulators are used. Thyristors themselves deal with phase changes. They can be used not only on transformers, but also on incandescent lamps, as well as on heaters.

If we consider active voltage, then circuits are required that can cope with a large load to carry out the inductive process. Some circuit engineers use triacs, but they are not suitable for transformers with a power greater than 300 V. The problem here is the spread of positive and negative polarities. Today, rectifier bridges can handle high active loads. Thanks to them, the control pulse ultimately reaches the holding current.

Simple regulator circuit

The circuit of a simple regulator directly includes a gate-type thyristor and a controller for controlling the limit voltage. Transistors are used to stabilize the current at the beginning of the circuit. Capacitors must be used in front of the controller. Some use combined analogues, but this is a controversial issue. In this case, the capacitance of the capacitors is estimated based on the power of the transformer. If we talk about negative polarity, then inductors are installed only with the primary winding. The connection to the microcontroller in the circuit can occur through an amplifier.

Is it possible to make a regulator yourself?

You can make a thyristor voltage regulator with your own hands, following standard circuits. If we consider high-voltage modifications, then it is best to use sealed type resistors. They can withstand maximum resistance at 6 ohms. As a rule, vacuum analogues are more stable in operation, but their active parameters are underestimated. In this case, it is better not to consider general-purpose resistors at all. On average, they can withstand a nominal resistance of only 2 ohms. In this regard, the regulator will have serious problems with current conversion.

For high power dissipation, class PP201 capacitors are used. They are distinguished by good accuracy, high-resistance wire is ideal for them. Lastly, a microcontroller with a circuit is selected. Low-frequency elements are not considered in this case. Single-channel modulators should only be used in conjunction with amplifiers. They are installed at the first and also at the second resistors.

Constant voltage devices

Thyristor constant voltage regulators are well suited for pulsed circuits. Capacitors in them, as a rule, are used only of the electrolytic type. However, they can be completely replaced with solid-state analogues. Good current carrying capacity is ensured by the rectifier bridge. For high precision of the regulator, combined type resistors are used. They can maintain a maximum resistance of 12 ohms. Only aluminum anodes can be present in the circuit. Their conductivity is quite good, the capacitor does not heat up very quickly.

The use of vacuum-type elements in devices is generally not justified. In this situation, thyristor DC voltage regulators will experience a significant reduction in frequency. To configure device parameters, CP1145 class microcircuits are used. As a rule, they are designed for multi-channel and have at least four ports. They have a total of six connectors. The failure rate in such a circuit can be reduced by using fuses. They should be connected to the power source only through a resistor.

AC Voltage Regulators

A thyristor AC voltage regulator has an average output power of 320 V. This is achieved due to the rapid occurrence of the inductance process. Rectifier bridges are used quite rarely in the standard circuit. Thyristors for regulators are usually four-electrode. They have only three exits. Due to their high dynamic characteristics, they can withstand a maximum resistance of 13 ohms.

The maximum output voltage is 200 V. Due to the high heat dissipation, amplifiers are absolutely not needed in the circuit. The thyristor is controlled using a microcontroller that is connected to the board. Turn-off transistors are installed in front of the capacitors. Also, high conductivity is ensured by the anode circuit. In this case, the electrical signal is quickly transmitted from the microcontroller to the rectifier bridge. Problems with negative polarity are solved by increasing the limit frequency to 55 Hz. The optical signal is controlled using electrodes at the output.

Battery charging models

The thyristor battery charging voltage regulator (the diagram is shown below) is distinguished by its compactness. It can withstand a maximum resistance in the circuit of 3 ohms. In this case, the current load can only be 4 A. All this indicates the weak characteristics of such regulators. Capacitors in the system are often used of a combined type.

In many cases their capacitance does not exceed 60 pF. However, much in this situation depends on their series. Transistors in regulators use low-power ones. This is necessary so that the dispersion index is not so large. Ballistic transistors are not suitable in this case. This is due to the fact that they can only pass current in one direction. As a result, the voltage at the input and output will be very different.

Features of regulators for primary transformers

The thyristor voltage regulator for the primary transformer uses emitter-type resistors. Thanks to this, the conductivity indicator is quite good. In general, such regulators are distinguished by their stability. The most common stabilizers are installed on them. IR22 class microcontrollers are used to control power. The current amplification factor in this case will be high. Transistors of the same polarity are not suitable for regulators of the indicated type. Experts also advise avoiding insulated gates for connecting elements. In this case, the dynamic characteristics of the regulator will be significantly reduced. This is due to the fact that the negative resistance at the output of the microcontroller will increase.

Thyristor regulator KU 202

The thyristor voltage regulator KU 202 is equipped with a two-channel microcontroller. It has three connectors in total. Diode bridges are used quite rarely in a standard circuit. In some cases, you can find various zener diodes. They are used exclusively to increase the maximum output power. They are also capable of stabilizing the operating frequency in regulators. It is more advisable to use capacitors in such devices of a combined type. Due to this, the dissipation coefficient can be significantly reduced. The throughput of the thyristors should also be taken into account. Bipolar resistors are best suited for the output anode circuit.

Modification with thyristor KU 202N

The KU 202N thyristor voltage regulator is capable of transmitting a signal quite quickly. Thus, the limiting current can be controlled at high speed. The heat transfer in this case will be low. The device should keep the maximum load at 5 A. All this will allow you to easily cope with interference of various amplitudes. Also, do not forget about the nominal resistance at the input of the circuit. Using these thyristors in regulators, the induction process is carried out with the locking mechanisms turned off.

KU 201l regulator diagram

The KU 201l thyristor voltage regulator includes bipolar transistors, as well as a multichannel microcontroller. Capacitors in the system are used only of the combined type. Electrolytic semiconductors are quite rare in regulators. Ultimately, this greatly affects the conductivity of the cathode.

Solid-state resistors are only needed to stabilize the current at the beginning of the circuit. Resistors with dielectrics can be used in conjunction with rectifier bridges. In general, these thyristors can boast high accuracy. However, they are quite sensitive and keep the operating temperature low. Due to this, the failure rate can be fatal.

Regulator with thyristor KU 201a

The capacitors are provided by a trimmer-type thyristor voltage regulator. Their nominal capacitance is 5 pF. In turn, they withstand a maximum resistance of exactly 30 ohms. High current conductivity is ensured by an interesting design of transistors. They are located on both sides of the power source. It is important to note that current passes through resistors in all directions. The PPR233 series microcontroller is presented as a closing mechanism. You can periodically adjust the system using it.

Parameters of the device with thyristor KU 101g

To connect to high-voltage transformers, the specified thyristor voltage regulators are used. Their circuits involve the use of capacitors with a maximum capacitance of 50 pF. Interlinear analogs cannot boast of such indicators. Rectifier bridges play an important role in the system.

Bipolar transistors can additionally be used to stabilize the voltage. Microcontrollers in devices must withstand a maximum resistance of 30 ohms. The induction process itself proceeds quite quickly. It is permissible to use amplifiers in regulators. In many ways, this will help increase the conductivity threshold. The sensitivity of such regulators leaves much to be desired. The maximum temperature of thyristors reaches 40 degrees. Because of this, they need fans to cool the system.

Properties of the regulator with thyristor KU 104a

The specified thyristor voltage regulators work with transformers whose power exceeds 400 V. The layout of their main elements may differ. In this case, the limiting frequency should be at 60 Hz. All this ultimately puts a huge load on the transistors. Here they are used closed type.

Due to this, the performance of such devices increases significantly. At the output, the operating voltage is on average 250 V. It is not advisable to use ceramic capacitors in this case. Also, a big question among experts is the use of trimming mechanisms to regulate the current level.