DIY power regulator for a soldering iron - diagram of a simple thermostat using a triac, thyristor, modification of a Chinese device, with indication and other options

There are many models of soldering irons in stores - from cheap Chinese ones to expensive ones with a built-in temperature controller; they even sell soldering stations.

Another thing is, is the same station needed if such work needs to be done once a year, or even less often? It's easier to buy an inexpensive soldering iron. And some people still have simple but reliable Soviet instruments at home. A soldering iron that is not equipped with additional functionality heats up as long as the plug is plugged in. And when turned off, it cools down quickly. An overheated soldering iron can ruin the work: it becomes impossible to solder anything firmly, the flux quickly evaporates, the tip oxidizes and the solder rolls off it. An insufficiently heated tool can completely ruin the parts - due to the fact that solder does not melt well, the soldering iron can be held close to the parts.

To make work more comfortable, you can assemble a power regulator with your own hands, which will limit the voltage and thereby prevent the soldering iron tip from overheating.

Switches and Dimmers

The simplest temperature control is used in soldering irons with a switch that allows only two positions, and, accordingly, two temperature values.
At the minimum value, the soldering iron mounted on the stand simply maintains the tip in a heated state, and when you press a key or button, the tip heats up to the maximum temperature at which soldering is performed.

Obviously, of the advantages described above, such a soldering iron only has the ability to save energy. The main task of adjustment - the production of high-quality and safe installation of components - remains impossible.

The second type of adjustable soldering irons is dimmable. Their design involves inserting a dimmer into the break in the power cable - a device that limits the power consumption of the soldering iron.

In this case, it really becomes possible to adjust the temperature of the tip, but this is done due to a voltage drop in the dimmer.

Accordingly, there can be no talk of any cost-effectiveness of such a scheme. But the price of such devices is quite low and can play a decisive role in the choice.

The use of control chips in the handle of the device

Soldering irons with a temperature control knob located on the handle are popular. Such devices operate on complex microcircuits. Not everyone will be able to make such a design on their own. The main difficulty is the correct firmware of the microcontroller, which is the main component of such a device. To install such a circuit, a radio amateur will need to have a programmer on hand, and experience in writing programs is also desirable.

Copper fixtures

The structure is made of copper wire twisted in a spiral pattern. Copper is capable of transmitting low current produced by small transformers. Adjustable heating components are equipped with a temperature sensor, which is responsible for controlling the tip. The thermocouple is installed on the working tip, which allows you to adjust the temperature level to the required state. The copper spiral does not pass electric current through itself, the performance of the unit stops, or the load indicator changes. Types of copper heaters:

with wire wound around the body, preventing voltage from reaching the tip;
The insulated structure avoids heat loss when using the device.

Homemade thermostat

The quality of copper depends on performance; adding additives in order to save money by the manufacturer can significantly reduce the service life and damage the parts being repaired.

Types of regulators

Devices for connecting various types of radio components have several types of characteristics. Soldering stations with heat and load adjustments are produced by the manufacturer with different parameter settings. Main varieties:

Changing the voltage and power of the node is possible using a triac. This modification is most common when using heating components in radio engineering.
Thyristor type adjusting element.
Modification to increase the performance of the device allows you to change the output force to the required values.
The indication makes it possible to recognize in which mode the heating is being carried out.
Low-voltage controllers are used in designs designed to operate with a voltage of no more than 36 Volts.

https://youtube.com/watch?v=et60fwS8w5E

You can probably make components that have adjustable temperature volumes with your own hands. A simple structure without interference is used, which makes it possible to extend the service life of the heating element. The galvanic component is considered reliable; its versatility allows the design to be used with various modifications and models.

Types of soldering irons with temperature control

All modern devices, used as individual power tools and as part of soldering stations, depending on the type of heating element and method of heating the tip, are divided into pulsed, devices with nichrome and ceramic heaters.

Pulse soldering iron

Pulse soldering gun
This soldering iron is a device that operates on mains power, reducing the mains voltage but increasing the frequency of the current. This device does not work all the time, only when you press a button on the handle. Thanks to this, it is more economical than analogues of other types, and allows soldering of very small and delicate radio components.

With nichrome heater

The classic nichrome heating element of such a device is a metal tube with fiberglass, mica and numerous turns of thin nichrome wire wound around it. When heated, the wire, which has high resistance, heats up the tube with the copper tip inserted into it.

With ceramic heater

Soldering iron with ceramic heater

In such devices, the tip is placed on a tubular ceramic heating element, which has electrical conductivity and high resistance. When current passes, this ceramic tube heats up almost instantly, providing the fastest possible heating of the tip installed on it.

DIY soldering iron regulators. Overview of installation methods

Depending on the type and set of radio components, power regulators for a soldering iron can be of different sizes, with different functionality. You can assemble either a small simple device, in which heating is stopped and resumed by pressing a button, or a large one, with a digital indicator and program control.

Possible types of installation in the housing: plug, socket, station

Depending on the power and tasks, the regulator can be placed in several types of housing. The simplest and most convenient one is a fork. To do this, you can use a cell phone charger or the housing of any adapter. All that remains is to find the handle and place it in the wall of the case. If the soldering iron body allows it (there is enough space), you can place the board with the parts in it.

Such a power regulator is always with the soldering iron - it cannot be forgotten or lost

Another type of housing for simple regulators is a socket. It can be either single or a tee-extension. In the latter you can very conveniently place a handle with a scale.

The case is convenient for placing a board with parts

In place of one and sockets there is a switch handle with a scale

There may also be several options for installing a regulator with a voltage indicator. It all depends on the radio amateur’s intelligence and imagination. This can be either the obvious option - an extension cord with an indicator built into it, or original solutions.

The counter on the body gives accurate numbers for work where a strictly defined temperature is important

The board is secured inside with screws

You can even assemble something like a soldering station and install a soldering iron stand on it (it can be purchased separately). When installing, we must not forget about safety rules. The parts need to be insulated - for example, with heat-shrink tubing.

DIY soldering iron power regulator: proven working circuits (6 pcs)

Not everyone likes to buy unknown things. And some people find it more pleasant to make a soldering iron power regulator with their own hands, because this is also experience. Most circuits are assembled using triacs and thyristors; now they are easier to find than transistors. They are also easier to work with, since they are either open or closed, which allows you to make circuits simpler.

Choose any case

Simple thyristor circuits

When choosing a power regulator circuit for a soldering iron, two things are important: power and parts availability. The soldering iron power regulator presented below is assembled using widely used parts that are not a problem to find. The maximum current is 10 A, which is more than enough to perform any kind of work and for soldering irons with a power of up to 100 W. The thyristor in this circuit is used KU202n

Pay attention to the bridge connection. There are many circuits with connection errors

This option is working. Tested more than once.

Temperature controller circuit for a soldering iron using a thyristor

When assembling the circuit, be sure to place the thyristor on the radiator; the larger it is, the better. The circuit is simple, but when it is turned on, it creates interference. You can’t listen to the radio nearby, and to remove interference, we connect a 200 pF capacitor in parallel with the load, and a choke in series. The choke parameters are selected depending on the regulated load, but since soldering irons are usually no more than 80-100 W, the choke can be made at 100 W. To do this, you will need a ferrite ring with an outer diameter of 20 mm, on which about 100 turns are wound with a wire with a cross-section of 0.4 mm².

Another drawback of the diagram translated above is that the soldering iron “itches” noticeably. Sometimes you can put up with this, sometimes you can’t. To eliminate this phenomenon, you can select the parameters of capacitor C1 so that when the variable resistor is set to maximum, the connected lamp barely glows.

On other elements but also without interference

The above regulator can be used for any load. Let's give another analogue, but using a different element base. You can regulate not only the power/temperature of the soldering iron, but also any other load with a small inductive component.

A modified circuit for regulating the power of a soldering iron and any other load with the ripple effect eliminated

There is pulsation here, but its frequency is high and it will not be perceived by our vision. So it can be used not only as a dimmer for a soldering iron, but also to regulate the light from a regular incandescent lamp. Is a diode bridge needed to regulate the heating power of a soldering iron? It won't hurt, but it's not necessary.

On a thyristor with high sensitivity

This circuit allows you to smoothly change the temperature of the soldering iron from 50% to 100%. There are two indicators - power and power. The power presence LED always lights up when turned on, but at 75% power the glow is brighter. The power indicator changes the intensity of the glow depending on the operating mode.

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Power regulator for soldering iron without interference

In order for the regulator to fit into the case of a mobile phone charger, resistances are used of SMD type (1206). All resistors are installed on the board, except for R 10. Some can be composite (we assemble the required value from series-connected resistors).

For normal operation of the circuit, a sensitive thyristor (with a low control current) and a low state holding current (about 1 mA) is required. For example, KT503 (designed for voltage 400 V, control current 1 mA). The rest of the element base is indicated in the diagram.

If assembled, but the voltage is not adjustable

If the assembled regulator does not regulate anything - the temperature of the soldering iron does not change - the problem is in the thyristor. The scheme seems to be working, but nothing happens. The reason is a thyristor with low sensitivity. The currents flowing in the circuit are not sufficient to open. In this case, it is worth installing an analogue with higher sensitivity (lower control currents).

One of the housing options in which you can hide a homemade power regulator for a soldering iron

The regulator may still work, but the soldering iron begins to “itch.” This problem is solved by installing a choke at the output (in front of the soldering iron). The capacity must be selected - it depends on the soldering iron. The second solution is an analog control circuit, and this is a different circuit.

Well, if you have problems with operation, look for either faulty parts or incorrectly selected components. This is usually the problem.

Power regulator for soldering iron 20-36 VAC

If the soldering iron operates from a network with reduced voltage, you will have to make a separate regulator for it.

Element base

To make such a device yourself, you will need to prepare the following components in advance:

Transistor KT815B. If this is not the case, you can install KT815G instead.
Diode bridge KTs401A. KTs402 B or S is also suitable for the regulator.
Diodes. For the power regulator it is better to use models from the D9 series.

You will also need capacitors. It is recommended to install oxide elements of type K50-6.

Installation features

To make such a regulator, you will have to order a printed circuit board layout in advance and place the entire element base on it. Particular attention must be paid to resistors. The fact is that their parameters are selected depending on the desired control limit.

It is recommended to place all components on an L-shaped radiator. It is necessary to install a socket on the front side or in the upper part of the regulator body to connect a soldering station.

Soldering iron with adjustable tip temperature: diagrams, types, application – Turner

To perform various electrical work and assemble electronic circuits, a tool such as an electric soldering iron is often used. Its simplest type, which can be purchased at any hardware store, usually has a basic design.

It includes a heating element, a tip, a handle, usually wooden, and a power cable or cord. In some versions, the soldering iron can be equipped with several replaceable tips.

The power of such a soldering iron is fixed, most often 40 or 60 watts. But it is more convenient to use a tool with the ability to adjust power. Such models are also produced, although they are more expensive.

DIY power regulator for a soldering iron - diagrams and installation options

There are many models of soldering irons in stores - from cheap Chinese ones to expensive ones with a built-in temperature controller; they even sell soldering stations.

And when turned off, it cools down quickly. An overheated soldering iron can ruin the work: it becomes impossible to solder anything firmly, the flux quickly evaporates, the tip oxidizes and the solder rolls off it.

To make work more comfortable, you can assemble a power regulator with your own hands, which will limit the voltage and thereby prevent the soldering iron tip from overheating.

Construction and details.

The regulator is assembled in the power supply housing of the once popular “Electronics B3-36” calculator.

The triac and potentiometer are placed on a steel angle made of steel 0.5 mm thick. The corner is screwed to the body with two M2.5 screws using insulating washers.

Resistors R2, R3 and neon lamp HL1 are dressed in an insulating tube (cambric) and mounted using a hinged mounting method on other electrical elements of the structure.

To increase the reliability of fastening the plug pins, I had to solder several turns of thick copper wire onto them.

This is what the power regulators I've been using for years look like.

Get the Flash Player to see this player.

And this is a 4-second video that allows you to make sure that it all works. The load is a 100 Watt incandescent lamp.

DIY device design

As follows from examination of the circuit, it consists of a power section, which should be mounted using surface-mounted installation, and a control circuit on a printed circuit board. By the way, they can solder the board at Solderpoint.ru.

Creating a PCB involves making a design of the board. For this purpose, the so-called LUT, which means laser-iron technology, is usually used in everyday conditions. The PCB manufacturing method includes the following steps:

creating a drawing;
transferring the design to the board blank;
etching;
cleaning;
drilling holes;
tinning of conductors.

To create an image of a board, the Sprint Layout program is most often used. After receiving the design using a laser printer, it is transferred to the foil getinax using a heated iron. Then the excess foil is etched using ferric chloride and the pattern is cleaned. Holes are drilled in the right places and the conductors are tinning. The elements of the control circuit are placed on the board and they are soldered (there are certain recommendations on how to solder correctly with a soldering iron).

Assembling the power part of the circuit includes connecting resistors R5, R6 and diode VD2 to the thyristor.

The last stage of assembly is placing the power section and control circuit board in the housing. The order of placement in the housing depends on its type.

Since the dimensions of the power regulator elements on a triac are small and there are few of them, you can use, for example, a plastic socket as a housing. The largest place there is occupied by a variable adjustment resistor and a powerful thyristor. However, as experience shows, all the elements of the circuit, together with the printed circuit board, fit into such a housing.

Temperature controller circuit for a soldering iron

Below is a simple diagram of a power regulator:

I used this circuit for my regulator about 20 years ago, I still use this soldering iron. Of course, some parts, such as transistors, a neon light bulb, can be replaced with modern ones.

Device details:

Transistors; KT 315G, MP 25 can be replaced with KT 361B
Thyristor; KU 202N
Zener diode; D 814B or with the letter B
Diode;KD 202Zh
Fixed resistors: MLT-3k, 2k-2 pcs, 30k, 100 ohm, 470k
Variable resistor; 100k
Capacitor; 0.1 µF

As you can see, the device diagram is very simple. Even a beginner can repeat it.

Making a simple soldering iron temperature controller with your own hands

The presented device is built according to the so-called half-wave power regulator. That is, with the thyristor VS 1 fully open, which is controlled by transistors VT 1 and VT 2, one half-wave of the mains voltage passes through the diode VD 1, and the other half-wave through the thyristor. If you turn the slider of the variable resistor R 2 in the opposite direction, then the thyristor VS 1 will close, and the load will have one half-wave that will pass through the diode VD 1:

Therefore, it is impossible to reduce the voltage below 110 volts with this regulator. As practice shows, this is not necessary, since at minimum voltage the temperature of the tip is so low that the tin barely melts.

The part ratings presented in the diagram are selected to work together with high-power soldering irons. If you do not need this, then the power elements, thyristor and diode can be replaced with less powerful ones. If you do not have a two-watt resistor R 5 with a nominal value of 30 kilo ohms, then it can be made up of two series-connected resistors of 15 kilo ohms, like mine:

This device does not require configuration. When assembled correctly and from serviceable parts, it starts working immediately.

Attention! Be careful. This temperature controller does not have galvanic isolation over the network

Secondary circuits have high potential.

All that remains is to choose the appropriate housing size. Place the soldering iron socket:

It is not necessary to take the fuse out; for example, I have it soldered into the break in the power cord. But the variable resistor needs to be installed in a convenient place and, of course, the scale must be calibrated, for example, in volts:

The resulting regulator is very reliable, which has been tested by time, and it will serve you for many years, and the soldering iron will thank you.

Classic thyristor regulator circuit

The classic thyristor circuit of the soldering iron power regulator did not meet one of my main requirements, the absence of radiating interference into the power supply network and the airwaves. But for a radio amateur, such interference makes it impossible to fully engage in what he loves. If the circuit is supplemented with a filter, the design will turn out to be bulky. But for many use cases, such a thyristor regulator circuit can be successfully used, for example, to adjust the brightness of incandescent lamps and heating devices with a power of 20-60 W. That's why I decided to present this diagram.

In order to understand how the circuit works, I will dwell in more detail on the principle of operation of the thyristor. A thyristor is a semiconductor device that is either open or closed. to open it, you need to apply a positive voltage of 2-5 V to the control electrode, depending on the type of thyristor, relative to the cathode (indicated by k in the diagram). After the thyristor has opened (the resistance between the anode and cathode becomes 0), it is not possible to close it through the control electrode. The thyristor will be open until the voltage between its anode and cathode (labeled a and k in the diagram) becomes close to zero. It's that simple.

Connecting the control device

Here is another version of the diagram, only simplified, with a minimum of details. 4 diodes are replaced by one VD1. The difference between this scheme is that the adjustment occurs when the network period is positive. The negative period, passing through the VD1 diode, remains unchanged, the power can be adjusted from 50% to 100%. If we exclude VD1 from the circuit, the power can be adjusted in the range from 0% to 50%.

If you use a KN102A dinistor in the gap between R1 and R2, you will have to replace C1 with a capacitor with a capacity of 0.1 μF. The following thyristor ratings are suitable for this circuit: KU201L (K), KU202K (N, M, L), KU103V, with a voltage of more than 300 V. Any diodes whose reverse voltage is not less than 300 V.

The above mentioned circuits are successfully suitable for adjusting incandescent lamps in lamps. It will not be possible to regulate LED and energy-saving lamps, as they have electronic control circuits. This will cause the lamp to flicker or run at full power, which will eventually damage it.

If you want to use regulators to operate on a 24.36 V network, you will have to reduce the resistor values and replace the thyristor with an appropriate one. If the power of the soldering iron is 40 W, the mains voltage is 36 V, it will consume 1.1 A.

Here is another very simple circuit of a thyristor power regulator, a simplified version of the classic regulator. The number of parts is kept to a minimum. Instead of four diodes VD1-VD4, one VD1 is used. Its operating principle is the same as the classical circuit. The circuits differ only in that the adjustment in this temperature controller circuit occurs only over the positive period of the network, and the negative period passes through VD1 without changes, so the power can only be adjusted in the range from 50 to 100%.

If you add a dinistor, for example KN102A, to the open circuit from R1 and R2, then the electrolytic capacitor C1 can be replaced with an ordinary one with a capacity of 0.1 mF. Thyristors for the above circuits are suitable, KU103V, KU201K (L), KU202K (L, M, N), designed for a forward voltage of more than 300 V. Diodes are also almost any, designed for a reverse voltage of at least 300 V.

The above circuits of thyristor power regulators can be successfully used to regulate the brightness of lamps in which incandescent light bulbs are installed. It will not be possible to adjust the brightness of lamps that have energy-saving or LED bulbs installed, since such bulbs have electronic circuits built in, and the regulator will simply disrupt their normal operation. The light bulbs will shine at full power or flicker and this may even lead to their premature failure.

Heating control

To heat a massive part to the required temperature, you need an equally massive soldering iron tip so that the heating rate is higher than the heat removal rate of the part.

A tool that can simultaneously cope with the tasks posed above is a fairly powerful soldering iron with temperature control.

That is, the maximum power of the soldering iron should be sufficient to heat large leads, and the temperature should be regulated within certain limits and selected in accordance with the operating conditions.

Then the massive tip will have greater thermal inertia and will heat the part to the required degree, without the risk of overheating.

There are several ways to adjust the temperature of the soldering iron:

maximum-minimum heating (simple switch);
dimmer adjustment;
the use of control microcircuits in the handle of the device;
external control unit;
using a hair dryer.

https://youtube.com/watch?v=MKZBAqnGoZ4

Using an adjustable soldering iron, in addition to the advantages described above, you can significantly save on electricity consumption for large volumes of work performed, extend the life of the device due to less time operating at maximum power, and reduce the amount of harmful substances released during high-temperature soldering.

DIY temperature regulator

Making a soldering iron with do-it-yourself adjustment requires knowledge of electrical engineering. If you have experience, it is proposed to make the mechanism from a conventional heating element with a power of 60 watts. High-quality connections can only be made when using a heating value balancer. Assembly is carried out by implementing some modifications and involves the use of available materials. The simplest system includes:

thyristor model KU101G;
resistor SP – 1;
diode operating at a current of at least 1A.

Thermostat circuit for a low-voltage soldering iron

Installation of the model is possible without the use of a board, in a power supply housing of any size. The connection is placed on the resistor body, to which the connector for adjusting the degree of heating is adjacent. The result is an adjustable device with an output power of up to 60 watts. A schematic drawing for more powerful devices includes slightly different components. Assembly is carried out on a circuit board; variable resistor R2 is responsible for adjustment, which operates in the range from 50 to 100%. The maximum permissible load is 300 watts, sufficient for a household device. Circuit options depending on the power limiter The power of the device can be adjusted in several ways, the differences lie in the use of a semiconductor controller that performs the necessary tasks. Schemes can be built using several components, depending on the purpose:

The thyristor works like an electronic switch; the current starts in one direction. The structure is made with three outputs, a cathode, an anode, and a control electrode. Applying a pulse to the electrode causes the thyristor to open; closing occurs after stopping the supply or changing the direction of the current.
Semiconductors that conduct current in both directions are called triacs. The housing has a control gate and power electrodes; the operation is essentially similar to two connected thyristors.
The design of control sensors uses parts known to radio amateurs, such as a resistor, diode, capacitor, and microcontroller.

In most cases, a thyristor or triac is used, the precise debugging is regulated using a microcontroller added to the circuit.

Triac power regulator

Using a boost triac that allows current to pass in both directions greatly simplifies the circuit and creates an efficient noise-free regulator. You only need a few details:

capacitor;
two resistors - constant and variable;
dinistor DIAC;
diode 1N4148/16 B;
LED that will act as a power indicator.

Installation of a triac can be done in different ways. If the soldering iron power reaches no more than 40 W, you can do without cooling. For large values, you will need to install an aluminum radiator on which a triac is mounted.

For soldering devices with a power of up to 100 W, power regulator circuits are made for a soldering iron with a triac model BTA 16600. They smoothly regulate the degree of heating of the soldering iron tip in the full voltage range, from 0 to 100% with a load from 130 to 220 volts.

The advantages of using such semiconductors:

costs for materials are minimized (the part is relatively inexpensive);
simplification of the electrical circuit diagram;
no contacts requiring fastening and insulation;
long operational period of devices equipped with triacs.

When connecting powerful devices over 100 W, a radiator or fan is included in the electrical circuit so that the semiconductor does not overheat during operation. The main thyristor is the KU202N model. Diodes of type D226 are suitable for the bridge jumper; they are selected according to the power load of the heating element.

Principle of operation

Parameters are adjusted using a special mechanism. A soldering iron with a thermostat consists of a tip, a housing, a board and a set of resistors in the structure. The design allows for heat adjustment when working with various parts. More expensive samples offer variable voltage limits

For each setting, you need to select the appropriate tip to control the output temperature. It is important for a novice radio amateur to determine what parameters a soldering iron is required with. Professionals in their field choose reliable models with temperature control

The equipment has good soldering performance, the action is carried out by meeting the necessary criteria. A different load is applied to each product; thermal stabilization allows you to select the boundaries necessary for high-quality soldering of various products.

Network soldering iron with temperature control

The temperature is selected in accordance with the description of the material and method of operation of the equipment used.

Selecting a suitable soldering iron power regulator circuit

A large number of different circuits are used to regulate power. Examples include:

with variable resistor;
with resistor and diode;
with a microcircuit and a field-effect transistor;
with a thyristor.

The simplest power regulator for a soldering iron is a circuit with a variable resistor. In this option, a variable resistor is connected in series with the soldering iron. The disadvantage of this scheme is that a lot of power is dissipated by the element, which goes into heat. In addition, a high-power variable resistor is a rather scarce element.

A more complex method is using a resistor and a rectifying diode. In this scheme there are three operating modes. In maximum mode, the soldering iron is connected directly to the network. In operating mode, a resistor is connected in series with the tool, which determines the optimal operating mode. When turned on in standby mode, the soldering iron is powered through a diode, which cuts off one half-cycle of the AC mains current. As a result, the power of the soldering iron is reduced by half.

When using a microcircuit and a field-effect transistor, the power of the soldering iron can be adjusted not only downward, but also upward. In this case, the circuit uses a rectifier bridge, the output voltage of which can reach 300 V. In series with a soldering iron for microcircuits, a powerful field-effect transistor of the KP707V2 type is included in the package.

The power of the soldering iron is controlled using the pulse width method. To do this, pulses with an average frequency of 30 kHz are applied to the transistor gate, generated using a multivibrator assembled on a K561LA7 type microcircuit. By changing the generation frequency, you can adjust the voltage on the soldering iron from ten to 300 V. As a result, the current of the tool and its heating temperature change.

The most common option used to regulate the power of a soldering iron is a circuit using a thyristor. It consists of a small number of non-deficient elements, which makes it possible to design such a regulator in very small dimensions. Next, we will consider the circuit of a triac power regulator for a soldering iron in more detail.

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Soldering iron power regulator with digital display from a watch designer for $1.5.

Author: Simurg Published 09.23.2021 Created using KotoEd.

Taking into account modern prices for AVR, STM, it is not rational to assemble simple devices for them. It is easier to make a regulator based on a Chinese watch designer. They contain a very good and bright indicator, which costs more than half the cost of the set if purchased separately. But here the bonus will be the board, the controller and the looseness! The board is almost suitable, you just need to make one jumper to free the INT0 pin from the indicator and reassign it to the pin of a button that we won’t need.

Regulation is carried out with one button. When the power decreases, a minus sign is displayed and the power value as a percentage decreases. As power increases, the minus sign goes out and the power value increases.

In the initial warm-up mode, the countdown timer runs at full power. The timer can be interrupted at any time by pressing the button. After the time has elapsed, the current power as a percentage will be displayed.

If there is no signal from the zero detector, or the input is used for overload protection when the protection is triggered, then the operation of the regulator and timer (if the time has not yet expired) is suspended and a message about this is displayed on the indicator in the form of dashes. Once the signal is restored, the soft start will be started again.

Adjustment with modulation of the control signal for a triac. This is necessary so that if the triac suddenly closes unplanned (especially when working on an inductive load), it is immediately opened again by the next modulation pulse. Also, thanks to modulation, you can use a pulse transformer to control the triac instead of the MOC3023. The program measures the duration of the half-cycle using a timer and uses it to calculate the opening angle in accordance with the specified percentage value.

The arrows indicate on the yellow diagram the moment of transition through 0, and on the blue diagram the moment of opening of the triac and modulation. When the value is 100%, the modulation pulses follow continuously.

If the 0 signal disappears in the next half-cycle, the operation will be stopped.

The proteus model is attached in the files. We take the cheapest constructor and use it for remodeling:

View from the paths.

After reworking the board, which consists of trimming one track and soldering one jumper, we get a power regulator that has the following functions:

— smooth start when turned on from 0 to 100% power;
— heating timer at full power 3 minutes;
— stop the timer at any time by pressing a button. Switch to displaying current power in %.
— after 3 minutes, automatic transition to 50% power;
- regulation with one button + and - with an accuracy of 1%;
— protection if the signal from the “0” detector disappears during half of the next period. Screen display “—-”;
-you can use the “0” detector input in the additional overcurrent protection function;
— smooth return to the set power after restoration of the signal from the “0” detector;
As a bonus, we will learn how to flash and write your programs for this controller and this clock designer in 1 day.

Let's add to the former clock any zero detector circuit on an optocoupler and a MOC3023 to control a triac and we get a power regulator.

The clock layout was originally like this:

We need to bring it to the form:

On the board it is necessary to release the INT0 P3.2 pin by transferring the indicator digit to the pin of the P3.4 button that we do not need and unsolder (or not solder) the resistor R3 and the S1 button. Connect the jumper to the battery diode that we no longer need. Also solder the resistors indicated by the arrows to improve performance.

For those who want to write their own program to suit their needs, a small step-by-step hint will help: You need to install the KEIL MVisionV5.11.2.0 program

Next, following the steps in the screenshots, perform a simple project setup: After installation, click the “Project” tab and select a new project

Come up with a name for your project:

Select the controller that is used in the AT89C2051 watch and click OK.

When asked to include a startup in the project, refuse by clicking NO.

An editor window will open. In it, right-click the Source Group 1 folder and select create a new file

Write the file name main and select the language C

Next, in the PROJECT tab, select project settings

In the TARGET tab, specify the frequency of the quartz used in the clock designer set 12.0 MHz. And according to the screenshot, set up optimization

In the OUTPUT tab, specify to create a HEX file, and disable the rest and click ok

Then right-click the Source Group 1 folder and select add new file. Here we will add a library file for working with a seven-segment indicator. Copy it in advance to your project folder

Find the folder and specify the indicator.c file and click add

Here you can write your own code, or copy the source code of the controller from any notepad.

Select the main.c file on the left and paste the code in the window that opens on the right.

Next we need to specify the paths to the folder with the .h files. To do this, right-click on Target 1 and in the PROJECT tab at the top select project settings as we did earlier. There, open the C51 tab and select the add patch button.

Here click on the dashed square CREATE

Click find folder

And specify the path to the folder with headers

Congratulations!!! Now you can compile the project. After compilation, if there are no errors, a firmware file will be created with the extension “your project name.HEX”. It will be located along the path indicated at the top in the blue line.

Now we need to upload the firmware to the controller using the Mini-Pro TL866A or TL866CS programmer or any other programmer and the MiniPro program. In the program, select the type of controller that we will program. Select AT89C2051.

Click open file. Select the .HEX file type and find your firmware file and click OPEN.

Make sure INTEL HEX is selected and click OK.

Insert the controller into the socket according to the picture in the program window and press the PROGRAM button.

Uncheck LOCK BIT and press PROGRAM

Insert the controller into the socket of our former clock, which has become a power regulator and make sure that everything works as intended.

Project files: firmware and proteus model.

Files:

vse

All questions in the Forum.

What do you think of this article?	Did this device work for you?
31	9	11

Converters based on controlled diodes

Each of the possible versions of the devices differs in its circuit and control element. There are circuits of power regulators using thyristors, triacs and other options.

Thyristor devices

In terms of their circuit design, most known control units are manufactured using a thyristor circuit controlled by a voltage specially generated for these purposes.

Triac converters

Another way to organize the control of a soldering iron involves the use of an electronic circuit built on a triac and also designed for a low-power load.

This circuit works on the principle of reducing the effective voltage value on the semiconductor rectifier, to which the payload (soldering iron) is connected.

The state of the control triac depends on the position of the “switch” of the variable resistor R1, which changes the potential at its control input. When the semiconductor device is completely open, the power supplied to the soldering iron is reduced by approximately half.

The simplest control option

The simplest voltage regulator, which is a “truncated” version of the two circuits discussed above, involves mechanical control of power in the soldering iron.

Such a power regulator is in demand in conditions where long breaks in work are expected and it does not make sense to keep the soldering iron on all the time.

In the open position of the switch, a small amplitude voltage (approximately 110 Volts) is supplied to it, ensuring a low heating temperature of the tip.

To bring the device into working condition, just turn on the S1 toggle switch, after which the soldering iron tip quickly heats up to the required temperature, and you can continue soldering.

Such a thermostat for a soldering iron allows you to reduce the temperature of the tip to a minimum value in the intervals between solderings. This feature slows down oxidative processes in the tip material and significantly extends its service life.

Thyristor voltage

First, let's figure out how a thyristor differs from a triac. A thyristor contains 3 pn junctions, and a triac contains 5 pn junctions. Without going into details, in simple terms, a triac conducts in both directions, while a thyristor conducts only in one. Graphic designations of the elements are shown in the figure. This is clearly visible from the graphics .

The operating principle is absolutely the same. This is what power regulation is based on in any circuit. Let's look at several thyristor-based regulator circuits. The first is the simplest circuit, which basically repeats the triac circuit described above. The second and third are using logic, circuits that better dampen the interference created in the network by switching thyristors.

Simple scheme

A simple phase control circuit on a thyristor is presented below.

Its only difference from the triac circuit is that only the positive half-wave of the mains voltage is adjusted. The timing RC circuit, by adjusting the resistance value of the potentiometer, regulates the trigger value, thereby setting the output power supplied to the load. On the oscillogram it looks like this.

From the oscillogram it can be seen that power regulation occurs by limiting the voltage supplied to the load. Figuratively speaking, the regulation consists of limiting the flow of mains voltage to the output. By adjusting the charging time of the capacitor by changing the variable resistance (potentiometer). The higher the resistance, the longer it takes to charge the capacitor and the less power will be transferred to the load. The physics of the process is described in detail in the previous diagram. In this case, it is no different.

With logic based generator

The second option is more complicated. Due to the fact that switching processes on thyristors cause great noise in the network, this has a bad effect on elements installed on the load. Especially if the load is a complex device with fine settings and a large number of microcircuits.

This DIY implementation of a thyristor power regulator is suitable for active loads, for example, a soldering iron or any heating devices. There is a rectifier bridge at the input, so both waves of the mains voltage will be positive. Please note that with such a circuit, an additional +9 V DC voltage source will be needed to power the microcircuits. Due to the presence of a rectifier bridge, the oscillogram will look like this.

Both half-waves will now be positive due to the influence of the rectifier bridge. If for reactive loads (motors and other inductive loads) the presence of oppositely polar signals is preferable, then for active ones a positive power value is extremely important. The thyristor also turns off when the half-wave approaches zero, the holding current is supplied to a certain value and the thyristor is turned off.

Based on transistor KT117

The presence of an additional constant voltage source can cause difficulties; if it is not there, you will have to install an additional circuit. If you do not have an additional source, then you can use the following circuit, in which the signal generator to the control output of the thyristor is assembled using a conventional transistor. There are circuits based on generators built on complementary pairs, but they are more complex, and we will not consider them here.

In this circuit, the generator is built on a dual-base transistor KT117, which, when used in this way, will generate control pulses with a frequency set by trimming resistor R6. The diagram also includes an indication system based on the HL1 LED.

VD1-VD4 is a diode bridge that rectifies both half-waves and allows for smoother power adjustment.
EL1 - incandescent lamp - is represented as a load, but it can be any other device.
FU1 is a fuse, in this case it is 10 A.
R3, R4 - current-limiting resistors - are needed so as not to burn the control circuit.
VD5, VD6 - zener diodes - perform the role of stabilizing the voltage at a certain level at the emitter of the transistor.
VT1 - transistor KT117 - must be installed with exactly this location of base No. 1 and base No. 2, otherwise the circuit will not work.
R6 is a tuning resistor that determines the moment when a pulse arrives at the control output of the thyristor.
VS1 - thyristor - element that provides switching.
C2 is a timing capacitor that determines the period of appearance of the control signal.

The remaining elements play a minor role and mainly serve to limit current and smooth out pulses. HL1 provides an indication and signals only that the device is connected to the network and is energized.

The simplest energy regulator

The first designs of devices that varied the power supplied to a load were based on Ohm's law: electrical power equals current times voltage or resistance times current squared. A device called a rheostat was designed on this principle. It is located both in series and in parallel with the connected load. By changing its resistance, the power is also adjusted.

The current entering the rheostat is divided between it and the load. When connected in series, the current and voltage are controlled, and when connected in parallel, only the value of the potential difference is controlled. Depending on the material from which the resistance is made, rheostats can be:

metal;
liquid;
coal;
ceramic.

According to the law of conservation of energy, the absorbed electrical energy cannot simply disappear, therefore, in resistors, power is converted into heat, and if its value is large, it must be removed from them. To ensure removal, cooling is used, which is performed by blowing or by immersing the rheostat in oil.

A rheostat is a fairly universal device. Its only, but significant, disadvantage is the generation of heat, which does not allow making a device with small dimensions if it is necessary to pass large amounts of power through it. By controlling current and voltage, a rheostat is often used in low-power lines of household appliances. For example, in audio equipment to adjust the volume. It is not at all difficult to make such a current regulator with your own hands; this applies to a greater extent to a wire rheostat.