SEVERAL SCHEMATIC DIAGRAMS OF POWER REGULATORS

POWER REGULATOR ON TRIAC

Features of the proposed device are the use of a D-trigger to build a generator synchronized with the mains voltage, and a method of controlling a triac using a single pulse, the duration of which is adjusted automatically. Unlike other methods of pulsed control of a triac, this method is not critical to the presence of an inductive component in the load. The generator pulses follow with a period of approximately 1.3 s.
The DD 1 microcircuit is powered by a current flowing through a protective diode located inside the microcircuit between its pins 3 and 14. It flows when the voltage at this pin, connected to the network through resistor R 4 and diode VD 5, exceeds the stabilization voltage of the zener diode VD 4 .

K. GAVRILOV, Radio, 2011, No. 2, p. 41

TWO-CHANNEL POWER CONTROL FOR HEATING DEVICES

The regulator contains two independent channels and allows you to maintain the required temperature for various loads: the temperature of a soldering iron tip, an electric iron, an electric heater, an electric stove, etc. The depth of regulation is 5...95% of the power of the supply network. The regulator circuit is powered by a rectified voltage of 9...11 V with transformer isolation from a 220 V network with low current consumption.

V.G. Nikitenko, O.V. Nikitenko, Radioamator, 2011, No. 4, p. 35

TRIAC POWER REGULATOR

A feature of this triac regulator is that the number of half-cycles of the mains voltage supplied to the load is even at any position of the control. As a result, a constant component of the consumed current is not formed and, therefore, there is no magnetization of the magnetic circuits of transformers and electric motors connected to the regulator. Power is regulated by changing the number of periods of alternating voltage applied to the load over a certain time interval. The regulator is designed to regulate the power of devices with significant inertia (heaters, etc.).
It is not suitable for adjusting the brightness of lighting, since the lamps will blink strongly.

V. KALASHNIK, N. CHEREMISINOVA, V. CHERNIKOV, Radiomir, 2011, No. 5, p. 17 - 18

INTERFERENCE-FREE VOLTAGE REGULATOR

Most voltage (power) regulators are made using thyristors according to a phase-pulse control circuit. It is known that such devices create a noticeable level of radio interference. The proposed regulator is free from this drawback. A feature of the proposed regulator is the control of the amplitude of the alternating voltage, in which the shape of the output signal is not distorted, unlike phase-pulse control.
The regulating element is a powerful transistor VT1 in the diagonal of the diode bridge VD1-VD4, connected in series with the load. The main disadvantage of the device is its low efficiency. When the transistor is closed, no current passes through the rectifier and the load. If control voltage is applied to the base of the transistor, it opens and current begins to flow through its collector-emitter section, diode bridge and load. The voltage at the regulator output (at the load) increases. When the transistor is open and in saturation mode, almost all the mains (input) voltage is applied to the load. The control signal is generated by a low-power power supply assembled on transformer T1, rectifier VD5 and smoothing capacitor C1.
The variable resistor R1 regulates the base current of the transistor, and therefore the amplitude of the output voltage. When the variable resistor slider is moved to the upper position in the diagram, the output voltage decreases, and to the lower position, it increases. Resistor R2 limits the maximum value of the control current. Diode VD6 protects the control unit in the event of breakdown of the collector junction of the transistor. The voltage regulator is mounted on a board made of foiled fiberglass laminate with a thickness of 2.5 mm. Transistor VT1 should be installed on a heat sink with an area of ​​at least 200 cm2. If necessary, diodes VD1-VD4 are replaced with more powerful ones, for example D245A, and are also placed on the heat sink.

If the device is assembled without errors, it starts working immediately and requires virtually no setup. You just need to select resistor R2.
With the KT840B regulating transistor, the load power should not exceed 60 W. It can be replaced with devices: KT812B, KT824A, KT824B, KT828A, KT828B with a permissible power dissipation of 50 W; KT856A -75 W; KT834A, KT834B - 100 W; KT847A-125 W. The load power can be increased if regulating transistors of the same type are connected in parallel: the collectors and emitters are connected to each other, and the bases are connected to the variable resistor motor through separate diodes and resistors.
The device uses a small-sized transformer with a voltage on the secondary winding of 5...8 V. The KTs405E rectifier unit can be replaced with any other one or assembled from individual diodes with a permissible forward current of no less than the required base current of the regulating transistor. The same requirements apply to the VD6 diode. Capacitor C1 - oxide, for example, K50-6, K50-16, etc., with a rated voltage of at least 15 V. Variable resistor R1 - any with a rated dissipation power of 2 W. When installing and setting up the device, precautions should be taken: the regulator elements are under mains voltage. Note: To reduce distortion of the sine wave output voltage, try eliminating capacitor C1. A. Chekarov

Voltage regulator based on MOSFET transistors (IRF540, IRF840)

Oleg Belousov, Electrician, 201 2, No. 12, p. 64 - 66

Since the physical principle of operation of a field-effect transistor with an insulated gate differs from the operation of a thyristor and triac, it can be turned on and off repeatedly during the period of mains voltage. The switching frequency of powerful transistors in this circuit is chosen to be 1 kHz. The advantage of this circuit is its simplicity and the ability to change the duty cycle of the pulses, while slightly changing the pulse repetition rate.

In the author's design, the following pulse durations were obtained: 0.08 ms, with a repetition period of 1 ms, and 0.8 ms, with a repetition period of 0.9 ms, depending on the position of the resistor R2 slider.
You can turn off the voltage on the load by closing switch S 1, while a voltage close to the voltage at pin 7 of the microcircuit is set at the gates of the MOSFET transistors. With the toggle switch open, the voltage at the load in the author's copy of the device could be changed with resistor R 2 within the range of 18...214 V (measured by a TES 2712 type device).
The schematic diagram of such a regulator is shown in the figure below. The regulator uses a domestic K561LN2 microcircuit on two elements of which a generator with adjustable sensitivity is assembled, and four elements are used as current amplifiers.

To avoid interference via the 220 network, it is recommended to connect a choke wound on a ferrite ring with a diameter of 20...30 mm in series with the load until it is filled with 1 mm of wire.

Load current generator based on bipolar transistors (KT817, 2SC3987)

Butov A.L., Radioconstructor, 201 2, No. 7, p. 11 - 12

To check the functionality and configure power supplies, it is convenient to use a load simulator in the form of an adjustable current generator. Using such a device, you can not only quickly set up a power supply and voltage stabilizer, but also, for example, use it as a stable current generator for charging and discharging batteries, electrolysis devices, for electrochemical etching of printed circuit boards, as a current stabilizer for electric lamps, for “soft” start of commutator electric motors.
The device is a two-terminal device, does not require an additional power source and can be connected to the power supply circuit of various devices and actuators.
Current adjustment range from 0...0, 16 to 3 A, maximum power consumption (dissipation) 40 W, supply voltage range 3...30 V DC. The current consumption is regulated by variable resistor R6. The further to the left the slider of resistor R6 is in the diagram, the more current the device consumes. With open contacts of switch SA 1, resistor R6 can set the consumption current from 0.16 to 0.8 A. With closed contacts of this switch, the current is regulated in the range of 0.7... 3 A.

Current generator circuit board drawing

Car battery simulator (KT827)

V. MELNICHUK, Radiomir, 201 2, No. 1 2, p. 7 - 8

When converting computer switching power supplies (UPS) and chargers for car batteries, the finished products must be loaded with something during the setup process. Therefore, I decided to make an analogue of a powerful zener diode with an adjustable stabilization voltage, the circuits of which are shown in Fig. 1 . Resistor R 6 can be used to regulate the stabilization voltage from 6 to 16 V. A total of two such devices were made. In the first version, KT 803 is used as transistors VT 1 and VT 2.
The internal resistance of such a zener diode turned out to be too high. So, at a current of 2 A, the stabilization voltage was 12 V, and at 8 A - 16 V. In the second version, composite transistors KT827 were used. Here, at a current of 2 A, the stabilization voltage was 12 V, and at 10 A - 12.4 V.

However, when regulating more powerful consumers, for example electric boilers, triac power regulators become unsuitable - they will create too much interference on the network. To solve this problem, it is better to use regulators with a longer period of ON-OFF modes, which clearly eliminates the occurrence of interference. One of the diagram options is shown.

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

Circuit of a simple triac regulator

Such a regulator can be used to regulate lighting with incandescent lamps, but also with LED lamps if you buy dimmable ones. It is easy to regulate the temperature of the soldering iron. You can continuously adjust the heating, change the rotation speed of electric motors with a wound rotor, and much more where there is a place for such a useful thing. If you have an old electric drill that does not have speed control, then by using this regulator you will improve such a useful thing.
The article, with the help of photographs, descriptions and the attached video, describes in great detail the entire manufacturing process, from collecting parts to testing the finished product.

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

• R1 – resistor approximately 20 Kom, power 0.25 W;
• R2 – potentiometer approximately 500 Kom, 300 Kom to 1 Mohm is possible, but 470 Kom is better;
• R3 - resistor approximately 3 Kom, 0.25 W;
• R4 - resistor 200-300 Ohm, 0.5 W;
• C1 and C2 – capacitors 0.05 μF, 400 V;
• C3 – 0.1 μF, 400 V;
• DB3 – dinistor, found in every energy-saving lamp;
• BT139-600, regulates a current of 18 A or BT138-800, regulates a current of 12 A - triacs, but you can take any others, depending on what kind of load you need to regulate. A dinistor is also called a diac, a triac is a triac.
• The cooling radiator is selected based on the planned regulation power, but the more, the better. Without a radiator, you can regulate no more than 300 watts.
• Any terminal blocks can be installed;
• Use the breadboard as you wish, as long as everything fits in.
• Well, without a device it’s like without hands. But it’s better to use our solder. Although it is more expensive, it is much better. I haven't seen any good Chinese solder.

Let's start assembling the regulator

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

After making sure that there are no errors and placing the product in a plastic case, you can test it by connecting it to the network.

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 need to get an output of 110 to 220 volts, use this diagram, which shows a half-wave power regulator on a thyristor.

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.

8 basic DIY regulator circuits. Top 6 brands of regulators from China. 2 schemes. 4 Most asked questions about voltage regulators.+ TEST for self-test

Voltage regulator is a specialized electrical device designed to smoothly change or adjust the voltage supplying an electrical device.

Voltage regulator

Important to remember! Devices of this type are designed to change and adjust the supply voltage, not the current. The current is regulated by the payload!

TEST:

4 questions on the topic of voltage regulators

1. Why do you need a regulator:

a) Change in voltage at the output of the device.

b) Breaking the electric current circuit

1. What does the regulator power depend on:

a) From the input current source and from the actuator

b) From the size of the consumer

1. The main parts of the device, which you can assemble yourself:

a) Zener diode and diode

b) Triac and thyristor

1. What are 0-5 volt regulators for?

a) Supply the microcircuit with a stabilized voltage

b) Limit the current consumption of electric lamps

Answers.

2 The most common do-it-yourself LV 0-220 volt circuits

Scheme No. 1.

The simplest and most convenient voltage regulator to use is regulator on thyristors connected in opposite directions. This will create a sinusoidal output signal of the required magnitude.

Input voltage up to 220V is supplied to the load through a fuse, and through the second conductor, through the power button, a sinusoidal half-wave reaches the cathode and anode thyristors VS1 and VS2. And through the variable resistor R2 the output signal is adjusted. Two diodes VD1 and VD2 leave behind only a positive half-wave arriving at the control electrode of one of thyristors, which leads to its discovery.

Important! The higher the current signal on the thyristor switch, the stronger it will open, that is, the more current it can pass through itself.

An indicator light is provided to control the input power, and a voltmeter is provided to adjust the output power.

Scheme No. 2.

A distinctive feature of this circuit is the replacement of two thyristors with one triac. This simplifies the circuit, makes it more compact and easier to manufacture.

The circuit also contains a fuse and a power button, and an adjusting resistor R3, and it controls the triac base; this is one of the few semiconductor devices with the ability to work with alternating current. Current passing through resistor R3 acquires a certain value, it will control the degree of opening triac. After this, it is rectified on the diode bridge VD1 and, through a limiting resistor, reaches the key electrode of the triac VS2. The remaining elements of the circuit, such as capacitors C1, C2, C3 and C4, serve to dampen the ripples of the input signal and filter it from extraneous noise and unregulated frequencies.

How to avoid 3 common mistakes when working with a triac.

1. The letter after the triac code indicates its maximum operating voltage: A – 100V, B – 200V, C – 300V, D – 400V. Therefore, you should not take a device with the letters A and B to adjust 0-220 volts - such a triac will fail.
2. A triac, like any other semiconductor device, gets very hot during operation; you should consider installing a radiator or an active cooling system.
3. When using a triac in load circuits with high current consumption, it is necessary to clearly select the device for the stated purpose. For example, a chandelier with 5 bulbs of 100 watts each will consume a total current of 2 amperes. When choosing from the catalog, you need to look at the maximum operating current of the device. So triac MAC97A6 is designed for only 0.4 amperes and will not withstand such a load, while MAC228A8 is capable of passing up to 8 A and is suitable for this load.

3 Key points when making a powerful LV and current with your own hands

The device controls loads up to 3000 watts. It is built on the use of a powerful triac, and it is controlled by a gate or key dinistor.

Dinistor- this is the same as a triac, only without a control output. If triac opens and begins to pass current through itself when a control voltage appears at its base and remains open until it disappears, then dinistor will open if a potential difference above the opening barrier appears between its anode and cathode. It will remain unlocked until the current between the electrodes drops below the locking level.

As soon as a positive potential hits the control electrode, it will open and allow alternating current to pass through, and the stronger this signal is, the higher the voltage will be between its terminals, and therefore across the load. To regulate the degree of opening, an decoupling circuit is used, consisting of a dinistor VS1 and resistors R3 and R4. This circuit sets the current limit on the switch triac, and capacitors smooth out ripples on the input signal.

2 basic principles in the manufacture of 0-5 volt pH

1. To convert the high input potential into a low constant potential, special LM series microcircuits are used.
2. The microcircuits are powered only by direct current.

Let's consider these principles in more detail and analyze a typical regulator circuit.

LM series microcircuits are designed to reduce high DC voltage to low values. For this purpose, there are 3 terminals in the device body:

• The first pin is the input signal.
• The second pin is the output signal.
• The third output is the control electrode.

The principle of operation of the device is very simple - the input high voltage of a positive value is supplied to the input output and then converted inside the microcircuit. The degree of transformation will depend on the strength and magnitude of the signal on the control “leg”. In accordance with the master pulse, a positive voltage will be created at the output from 0 volts to the limit for this series.

The input voltage, no higher than 28 volts and must be rectified, is supplied to the circuit. You can take it from the secondary winding of the power transformer or from a high voltage regulator. After this, the positive potential is supplied to the pin of microcircuit 3. Capacitor C1 smoothes out the ripple of the input signal. Variable resistor R1 with a value of 5000 ohms sets the output signal. The higher the current it allows through itself, the higher the chip opens. The output voltage of 0-5 volts is removed from output 2 and goes to the load through smoothing capacitor C2. The higher the capacitance of the capacitor, the smoother the output.

Voltage regulator 0 - 220v

Top 4 stabilizing microcircuits 0-5 volts:

1. KR1157– a domestic microcircuit, with an input signal limit of up to 25 volts and a load current of no higher than 0.1 ampere.
2. 142EN5A– a microcircuit with a maximum output current of 3 amperes, no higher than 15 volts is supplied to the input.
3. TS7805CZ– a device with permissible currents up to 1.5 amperes and increased input voltage up to 40 volts.
4. L4960– a pulse microcircuit with a maximum load current of up to 2.5 A. The input voltage should not exceed 40 volts.

RN on 2 transistors

This type is used in circuits of particularly powerful regulators. In this case, the current to the load is also transmitted through a triac, but the key output is controlled through a cascade transistors. This is implemented like this: a variable resistor regulates the current that flows to the base of the first low-power transistor, which, through the collector-emitter junction, controls the base of the second high-power one transistor and he already opens and closes the triac. This implements the principle of very smooth control of huge load currents.

Answers to the 4 most frequently asked questions regarding regulators:

1. What is the permissible deviation of the output voltage? For factory instruments of large companies, the deviation will not exceed + -5%
2. What does the regulator power depend on? The output power directly depends on the power source and on the triac that switches the circuit.
3. What are 0-5 volt regulators for? These devices are most often used to power microcircuits and various circuit boards.
4. Why do you need a 0-220 volt household regulator? They are used for smooth switching on and off of household electrical appliances.

4 DIY LV circuits and connection diagram

Let's briefly consider each of the schemes, features, and advantages.

Scheme 1.

A very simple circuit for connecting and smoothly adjusting a soldering iron. Used to prevent the soldering iron tip from burning and overheating. The circuit uses a powerful triac, which is controlled by a thyristor-variable chain resistor.

Scheme 2.

The circuit is based on the use of a phase control microcircuit of the type 1182PM1. It controls the degree of opening triac, which controls the load. They are used to smoothly control the degree of luminosity of incandescent light bulbs.

Scheme 3.

The simplest scheme for regulating the heat of a soldering iron tip. Made according to a very compact design using easily accessible components. The load is controlled by one thyristor, the degree of activation of which is regulated by a variable resistor. There is also a diode to protect against reverse voltage. The thyristor,

Chinese LV 220 volt

Nowadays, goods from China have become quite a popular topic, and Chinese voltage regulators do not lag behind the general trend. Let's look at the most popular Chinese models and compare their main characteristics.

It is possible to choose any regulator specifically for your requirements and needs. On average, one watt of useful power costs less than 20 cents, and this is a very competitive price. But still, it is worth paying attention to the quality of parts and assembly; for goods from China it still remains very low.

Noise-free voltage regulator 220/0-220 volts 60 watts

Most voltage (power) regulators are made using thyristors according to a phase-pulse control circuit. It is known that such devices create a noticeable level of radio interference. The regulator proposed by the author of the article is free from this drawback.

A feature of the proposed regulator (see diagram) is the control of the amplitude of the alternating voltage, in which the shape of the output signal is not distorted, unlike phase-pulse control. The regulating element is a powerful transistor VT1 in the diagonal of the diode bridge VD1-VD4, connected in series with the load. The main disadvantage of the device is its low efficiency.

When the transistor is closed, no current passes through the rectifier and the load. If control voltage is applied to the base of the transistor, it opens and current begins to flow through its collector-emitter section, diode bridge and load. The voltage at the regulator output (at the load) increases. When the transistor is open and in saturation mode, almost all the mains (input) voltage is applied to the load.

The control signal is generated by a low-power power supply assembled on transformer T1, rectifier VD5 and smoothing capacitor C1. The variable resistor R1 regulates the base current of the transistor, and therefore the amplitude of the output voltage. When the variable resistor slider is moved to the upper position in the diagram, the output voltage decreases, and to the lower position, it increases. Resistor R2 limits the maximum value of the control current.

Diode VD6 protects the control unit in the event of breakdown of the collector junction of the transistor.

The voltage regulator is mounted on a board made of foil fiberglass 2.5 mm thick. Transistor VT1 should be installed on a heat sink with an area of ​​at least 200 cm2. If necessary, diodes VD1-VD4 are replaced with more powerful ones, for example D245A, and are also placed on the heat sink.

If the device is assembled without errors, it starts working immediately and requires virtually no setup. You just need to select resistor R2.

With the KT840B regulating transistor, the load power should not exceed 60 W. It can be replaced with devices: KT812B, KT824A, KT824B, KT828A, KT828B with a permissible power dissipation of 50 W; KT856A -75 W; KT834A, KT834B - 100 W; KT847A - 125W.

The load power can be increased if regulating transistors of the same type are connected in parallel: the collectors and emitters are connected to each other, and the bases are connected to the variable resistor motor through separate diodes and resistors.

The device uses a small-sized transformer with a voltage on the secondary winding of 5...8 V. The KTs405E rectifier unit can be replaced with any other one or assembled from individual diodes with a permissible forward current of no less than the required base current of the regulating transistor. The same requirements apply to the VD6 diode.

Capacitor C1 - oxide, for example, K50-6, K50-16, etc., with a rated voltage of at least 15 V. Variable resistor R1 - any with a rated dissipation power of 2 W.

When installing and setting up the device, precautions should be taken: the regulator elements are under mains voltage.

Literature

1. Radio No. 11, 1999 p.40

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