Many people's work involves using a soldering iron. For some it's just a hobby. Soldering irons are different. They can be simple but reliable, they can be modern soldering stations, including infrared ones. To obtain high-quality soldering, you need to have a soldering iron of the required power and heat it to a certain temperature.

Figure 1. Temperature controller circuit assembled on the KU 101B thyristor.

To help in this matter, various temperature regulators for the soldering iron are designed. They are sold in stores, but skilled hands can independently assemble such a device, taking into account their requirements.

Advantages of temperature controllers

Most home craftsmen use a 40 W soldering iron from a young age. Previously, it was difficult to buy something with other parameters. The soldering iron itself is convenient; you can use it to solder many objects. But it is inconvenient to use it when installing radio-electronic circuits. This is where the help of a temperature controller for a soldering iron comes in handy:

Figure 2. Diagram of a simple temperature controller.

• the soldering iron tip warms up to the optimal temperature;
• the service life of the tip is extended;
• radio components will never overheat;
• there will be no delamination of current-carrying elements on the printed circuit board;
• If there is a forced break in work, the soldering iron does not need to be turned off from the network.

An excessively heated soldering iron does not hold solder on the tip; it drips from an overheated soldering iron, making the soldering area very fragile. The sting is covered with a layer of scale, which can only be cleaned off with sandpaper and files. As a result, craters appear, which also need to be removed, reducing the length of the tip. If you use a temperature regulator, this will not happen; the tip will always be ready for use. During a break in work, it is enough to reduce its heating without unplugging it from the network. After the break, the hot tool will quickly reach the desired temperature.

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Simple temperature controller circuits

As a regulator, you can use a LATR (laboratory transformer), a dimmer for a table lamp, a KEF-8 power supply, or a modern soldering station.

Figure 3. Switch diagram for the regulator.

Modern soldering stations are able to regulate the temperature of the soldering iron tip in different modes - manually, fully automatically. But for a home craftsman, their cost is quite significant. From practice it is clear that automatic adjustment is practically not needed, since the voltage in the network is usually stable, and the temperature in the room where soldering is carried out also does not change. Therefore, for assembly a simple temperature controller circuit assembled on a KU 101B thyristor can be used (Fig. 1). This regulator is successfully used to work with soldering irons and lamps with power up to 60 W.

This regulator is very simple, but allows you to change the voltage within 150-210 V. The duration of the thyristor in the open state depends on the position of the variable resistor R3. This resistor regulates the voltage at the output of the device. The adjustment limits are set by resistors R1 and R4. By selecting R1, the minimum voltage is set, R4 - the maximum. The D226B diode can be replaced with any one with a reverse voltage of more than 300 V. The thyristor is suitable for KU101G, KU101E. For a soldering iron with a power of over 30 W, you need to take a D245A diode and a KU201D-KU201L thyristor. The board after assembly may look something like the one shown in Fig. 2.

To indicate the operation of the device, the regulator can be equipped with an LED, which will glow when there is voltage at its input. A separate switch will not be superfluous (Fig. 3).

Figure 4. Diagram of a temperature controller with a triac.

The following regulator circuit has proven itself to be good (Fig. 4). The product turns out to be very reliable and simple. Minimum details required. The main one is the KU208G triac. Of the LEDs, it is enough to leave HL1, which will signal the presence of voltage at the input and the operation of the regulator. The housing for the assembled circuit can be a suitable sized box. For this purpose, you can use the housing of an electrical outlet or switch with an installed power cord and plug. The axis of the variable resistor must be brought out and a plastic handle placed on it. You can put divisions nearby. Such a simple device is able to regulate the heating of the soldering iron within the range of approximately 50-100%. In this case, the load power is recommended within 50 W. In practice, the circuit worked with a load of 100 W without consequences for an hour.

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In order to obtain high-quality and beautiful soldering, it is necessary to maintain a certain temperature of the soldering iron tip, depending on the brand of solder used. I offer a homemade soldering iron heating temperature controller, which can successfully replace many industrial ones that are incomparable in price and complexity.

The main difference between the circuit of the presented soldering iron temperature controller and many existing ones is its simplicity and complete absence of radiated radio interference into the electrical network, since all transient processes occur at a time when the voltage in the supply network is zero.

Electrical circuit diagrams of soldering iron temperature controllers

Attention, the temperature controller circuits below are not galvanically isolated from the electrical network and touching the current-carrying elements of the circuit is dangerous to life!

To adjust the temperature of the soldering iron tip, soldering stations are used, in which the optimal temperature of the soldering iron tip is maintained in manual or automatic mode. The availability of a soldering station for a home craftsman is limited by its high price. For myself, I solved the issue of temperature regulation by developing and manufacturing a regulator with manual, stepless temperature control. The circuit can be modified to automatically maintain the temperature, but I don’t see the point in this, and practice has shown that manual adjustment is quite sufficient, since the voltage in the network is stable and the temperature in the room is also stable.

When starting to develop a temperature controller for a soldering iron, I proceeded from the following considerations. The circuit must be simple, easily repeatable, components must be cheap and available, high reliability, minimal dimensions, efficiency close to 100%, no radiated interference, and the possibility of upgrading.

Classic thyristor regulator circuit

The classic thyristor circuit of the soldering iron temperature controller 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 2-5V 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 (indicated a and k in the diagram) becomes close to zero. It's that simple.

The classical regulator circuit works as follows. The mains voltage is supplied through a load (incandescent light bulb or soldering iron winding) to a rectifier bridge circuit made using diodes VD1-VD4. The diode bridge converts alternating voltage into direct voltage, varying according to a sinusoidal law (diagram 1). When the middle terminal of resistor R1 is in the extreme left position, its resistance is 0 and when the voltage in the network begins to increase, capacitor C1 begins to charge. When C1 is charged to a voltage of 2-5V, current will flow through R2 to the control electrode VS1. The thyristor will open, short-circuit the diode bridge and the maximum current will flow through the load (top diagram). When you turn the knob of the variable resistor R1, its resistance will increase, the charge current of capacitor C1 will decrease and it will take more time for the voltage on it to reach 2-5V, so the thyristor will not open immediately, but after some time. The greater the value of R1, the longer the charging time of C1 will be, the thyristor will open later and the power received by the load will be proportionally less. Thus, by rotating the variable resistor knob, you control the heating temperature of the soldering iron or the brightness of the incandescent light bulb.

The simplest thyristor regulator circuit

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%. To adjust the heating temperature of the soldering iron tip, no more is required. If diode VD1 is excluded, the power adjustment range will be from 0 to 50%.


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 0.1mF. Thyristors for the above circuits are suitable, KU103V, KU201K (L), KU202K (L, M, N), designed for forward voltage more than 300V. Diodes are also almost any, designed for a reverse voltage of at least 300V.

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.

The circuits can be used for adjustment with a supply voltage of 36V or 24V AC. You just need to reduce the resistor values ​​by an order of magnitude and use a thyristor that matches the load. So a soldering iron with a power of 40 watts at a voltage of 36V will consume a current of 1.1A.

Thyristor circuit of the regulator does not emit interference

Since I was not satisfied with the regulators that emitted interference, and there was no suitable ready-made temperature controller circuit for the soldering iron, I had to start developing it myself. The temperature controller has been in trouble-free service for more than 5 years.


The temperature controller circuit works as follows. The voltage from the supply network is rectified by the diode bridge VD1-VD4. From a sinusoidal signal, a constant voltage is obtained, varying in amplitude as half a sinusoid with a frequency of 100 Hz (diagram 1). Next, the current passes through the limiting resistor R1 to the zener diode VD6, where the voltage is limited in amplitude to 9 V, and has a different shape (diagram 2). The resulting pulses charge the electrolytic capacitor C1 through the diode VD5, creating a supply voltage of about 9V for the microcircuits DD1 and DD2. R2 performs a protective function, limiting the maximum possible voltage on VD5 and VD6 to 22V, and ensures the formation of a clock pulse for the operation of the circuit. From R1, the generated signal is supplied to the 5th and 6th pins of the 2OR-NOT element of the logical digital microcircuit DD1.1, which inverts the incoming signal and converts it into short rectangular pulses (diagram 3). From pin 4 of DD1, pulses are sent to pin 8 of D trigger DD2.1, operating in RS trigger mode. DD2.1, like DD1.1, performs the function of inverting and signal generation (Diagram 4). Please note that the signals in diagram 2 and 4 are almost the same, and it seemed that the signal from R1 could be applied directly to pin 5 of DD2.1. But studies have shown that the signal after R1 contains a lot of interference coming from the supply network, and without double shaping the circuit did not work stably. And installing additional LC filters when there are free logic elements is not advisable.

The DD2.2 trigger is used to assemble a control circuit for the soldering iron temperature controller and it works as follows. Pin 3 of DD2.2 receives rectangular pulses from pin 13 of DD2.1, which with a positive edge overwrite at pin 1 of DD2.2 the level that is currently present at the D input of the microcircuit (pin 5). At pin 2 there is a signal of the opposite level. Let's consider the operation of DD2.2 in detail. Let's say at pin 2, logical one. Through resistors R4, R5, capacitor C2 will be charged to the supply voltage. When the first pulse with a positive drop arrives, 0 will appear at pin 2 and capacitor C2 will quickly discharge through the diode VD7. The next positive drop at pin 3 will set a logical one at pin 2 and through resistors R4, R5, capacitor C2 will begin to charge. The charging time is determined by the time constant R5 and C2. The greater the value of R5, the longer it will take for C2 to charge. Until C2 is charged to half the supply voltage, there will be a logical zero at pin 5 and positive pulse drops at input 3 will not change the logical level at pin 2. As soon as the capacitor is charged, the process will repeat.

Thus, only the number of pulses specified by resistor R5 from the supply network will pass to the outputs of DD2.2, and most importantly, changes in these pulses will occur during the voltage transition in the supply network through zero. Hence the absence of interference from the operation of the temperature controller.

From pin 1 of the DD2.2 microcircuit, pulses are supplied to the DD1.2 inverter, which serves to eliminate the influence of the thyristor VS1 on the operation of DD2.2. Resistor R6 limits the control current of thyristor VS1. When a positive potential is applied to the control electrode VS1, the thyristor opens and voltage is applied to the soldering iron. The regulator allows you to adjust the power of the soldering iron from 50 to 99%. Although resistor R5 is variable, adjustment due to the operation of DD2.2 heating the soldering iron is carried out in steps. When R5 is equal to zero, 50% of the power is supplied (diagram 5), when turning at a certain angle it is already 66% (diagram 6), then 75% (diagram 7). Thus, the closer to the design power of the soldering iron, the smoother the adjustment works, which makes it easy to adjust the temperature of the soldering iron tip. For example, a 40 W soldering iron can be configured to run from 20 to 40 W.
Temperature controller design and details

All parts of the temperature controller are located on the printed circuit board. Since the circuit does not have galvanic isolation from the power supply, the board is placed in a small plastic box, which also serves as a plug. The rod of the variable resistor R5 is fitted with a plastic handle.


The cord coming from the soldering iron is soldered directly to the printed circuit board. You can make the connection of the soldering iron detachable, then it will be possible to connect other soldering irons to the temperature controller. Surprisingly, the current consumed by the temperature controller control circuit does not exceed 2 mA. This is less than what the LED in the lighting circuit of the light switches consumes. Therefore, no special measures are required to ensure the temperature conditions of the device.
Microcircuits DD1 and DD2 are any 176 or 561 series. Diodes VD1-VD4 are any, designed for a reverse voltage of at least 300V and a current of at least 0.5A. VD5 and VD7 any pulse. Zener diode VD6 is any low-power one with a stabilization voltage of about 9V. Capacitors of any type. Any resistors, R1 with a power of 0.5 W. There is no need to adjust the temperature controller. If the parts are in good condition and there are no installation errors, it will work immediately.

Mobile soldering iron

Even people who are familiar with a soldering iron are often stopped by the inability to solder wires due to the lack of electrical connection. If the soldering site is not far away and it is possible to extend an extension cord, then it is not always safe to work with a soldering iron powered from a 220-volt electrical network in rooms with high humidity and temperature, with conductive floors. To be able to solder anywhere and safely, I offer a simple version of a stand-alone soldering iron.

Powering the soldering iron from the computer's UPS battery

By connecting the soldering iron to the battery using the method below, you will not be tied to the electrical network and will be able to solder wherever needed without extension cords in compliance with the requirements of the rules for safe work.
It is clear that in order to solder autonomously, you need a larger capacity battery. I immediately remember the automobile one. But it is very heavy, from 12 kg. However, there are other battery sizes, for example, those used in uninterruptible power supplies (UPS) for computer equipment. Weighing only 1.7 kg, they have a capacity of 7 Ah and produce a voltage of 12 V. Such a battery can be easily transported.

In order to make an ordinary soldering iron mobile, you need to take a plate of plywood, drill 2 holes in it with a diameter equal to the thickness of the soldering iron support wire and glue the plate to the battery. When bending the support, the width of the place where the soldering iron is installed should be made slightly smaller than the diameter of the tube with the heater of the soldering iron. Then the soldering iron will be inserted with tension and fixed. It will be convenient to store and transport.

For soldering wires with a diameter of up to 1 mm, a soldering iron designed to operate at a voltage of 12 volts and a power of 15 watts or more is suitable. The time of continuous operation from a freshly charged soldering iron battery will be more than 5 hours. If you plan to solder wires of larger diameter, then you need to take a soldering iron with a power of 30 - 40 watts. Then the continuous operation time will be at least 2 hours.

Batteries are quite suitable for powering a soldering iron, since they can no longer ensure the normal operation of uninterruptible power supplies due to the loss of their capacity over time. After all, to power a computer you need at least 250 watts of power. Even if the battery capacity has decreased to 1 A*hour, it will still provide operation of a 30-watt soldering iron for 15 minutes. This time is quite enough to complete the work of soldering several conductors.

In case of a one-time need to perform soldering, you can temporarily remove the battery from the uninterruptible power supply and return it to its place after soldering.

All that remains is to install connectors on the ends of the soldering iron wire by pressing or soldering, put them on the battery terminals and the mobile soldering iron is ready for use. Chapter.

A soldering iron with temperature control allows you to set the required soldering temperature for low-temperature soldering and tinning to heat parts, flux and solder, depending on the materials used, and also effectively combat the phenomenon of tip overheating. Such a tool is also called adjustable or with a power regulator. At the same time, the power ranges from 3 to 400 W, which allows the same soldering iron to solder microcircuits, radio components, wires, large parts made of different metals and even non-metals, ensure a tight fit, eliminate porosity, etc.

Design Features and Benefits

Russian and foreign manufacturers produce soldering devices with a power regulator in 3 versions:

• with built-in housing (the tool has low power);
• in the form of a separately located block with temperature control over a wide range;
• as part of soldering stations.

The design of a low-power soldering iron may contain a rotary dimmer (dimmer), which allows you to change the amount of electrical power, either increasing it or decreasing it. It is connected to a break in the power cable. In this case, the heating temperature is regulated by a voltage drop, which leads to a drop in power.

The simplest voltage regulator has only 2 regulation ranges. The maximum temperature for which it is designed can be set to perform the soldering process and the minimum temperature to maintain the heating temperature of the tip.

Using a soldering station, the temperature of the tool tip is adjusted with high precision. Moreover, if the station is equipped with a hot air gun, this allows soldering without limiting the amount of power. The power supply and electronic control system are located in a separate unit. A properly selected soldering station will ensure the highest quality soldering of any electronic circuit components.

The advantage of a tool equipped with a power regulator:

• when soldering, damage to parts sensitive to the soldering temperature is eliminated and the tracks on the board do not peel off;
• performance is not affected by changing the brand of solder;
• the flux does not smoke;
• the tip does not wear out;
• the tip does not overheat;
• electrical energy consumption is saved;
• the service life of the tool is extended.

Purchased designs of such temperature-controlled devices are not cheap; their price depends on the design features. Soldering stations with a hot air gun are especially expensive. Therefore, if you have certain skills and knowledge, you can make an adjustable soldering iron of either the simplest or more complex design.

You can assemble a power regulator for a soldering iron with your own hands using primitive circuits and using a microprocessor with information display. This depends on the desire, qualifications and capabilities of the person who wants to make such a device, because the final result of soldering determines the quality of operation of any device where electronic components are present in the circuit. With a little time, you can make your existing soldering iron adjustable.

The simplest power regulator made from a wirewound resistor

You can create the simplest temperature controller for a soldering iron with your own hands using only 2 elements: a wirewound resistor with a power of 25 W, a resistance of 1 kOhm (SP5-30) and a rotary knob. The resistor must be enclosed in a housing (necessarily made of dielectric material), securely fastening it there. All that remains is to put the handle on the resistor axis and you can smoothly regulate the power. Sockets for the plug are made on the body, or soldering iron wires are soldered, and a scale is installed. The simplest device is ready.

Note! The power of such a tool does not exceed 25 W.

Two-stage power regulator

To manufacture a two-stage device, you will need 2 elements: a 1N4007 rectifier diode for a current of 1 A and a switch. The product is adjusted as follows: when the switch is switched into the operating position, voltage is applied to the tip; when it is opened, it drops by half, which allows the tip temperature to be maintained in a gentle mode, i.e. it does not overheat and does not cool down. The device has proven itself well in cases where you have to take breaks from work.

The parts are connected parallel to each other in the break of the supply wires. You can supplement the circuit with an LED by connecting it to the output of the regulator. The output voltage is determined by the brightness of the glow. In this case, a limiting resistor must be present in the circuit. It is connected in series with the LED.

Dual-mode thyristor circuit

A device manufactured according to the diagram shown in Fig. below, is used for soldering irons with a power not exceeding 40 W. You will need a diode with a current of no more than 1 A for a voltage of 400 V, a KU101G thyristor and an SP-1 resistor. It is assembled in a case from a failed charger, or any other plastic box can be used for these purposes. You can use a single or tee extension socket housing.

For high-power soldering irons (up to 300 W), the regulator is assembled according to the diagram shown in Fig. higher.

Here 2 parts (power and control) are made separately. This device works as follows: when the thyristor is closed (its operation is controlled by 2 transistors), half of the supply voltage is supplied to the tip. Resistor R2 regulates the temperature in the range of 50 ÷ 100%. All parts must be placed on the board (see figure below), which is then placed in the housing of the extension socket or any other whose dimensions are suitable.

Note! All component leads should be insulated with heat shrink tubing to prevent shorting.

Power regulator with information display

The figure above shows a schematic diagram of a thermostat on a microcontroller. With its help, the power level is displayed on the indicator and the device is turned off if it is not working for a long time. Power information is displayed with numbers from 0 to 9, where zero means the device is not turned on. Numbers from 1 to 9 symbolize the light level, with 9 indicating full power operation. Using 2 buttons you can decrease or increase the voltage value.

The device has 2 modules (boards): power and digital. A regulator for a soldering iron is assembled on the widely used microcontroller PIC16F628A. Clocking is performed by a built-in oscillator at a frequency of 4 MHz. The power board has elements without transformer power supply and a filter that serves to reduce interference. The digital board contains components such as a microcontroller and a seven-segment indicator.

Variable resistance regulates the duration of the pulses. It is possible to place all the elements of the circuit on one board, but this will make the device bulky. And so these 2 boards will fit in a small case, for example, a plastic soap dish.

Power regulator using triac

A triac is two thyristors connected together. This allows current to flow in both directions. With its help, the power is adjusted from 0 to 100%. In the first case, to create a circuit you will need only 7 parts (2 resistors, a capacitor, a diode, a dynistor, a triac and an LED), in the second - 11 parts (5 resistors, a diode bridge, 2 capacitors, 2 diodes and a triac). Their denominations are indicated on the diagrams.

Functionality check

Regardless of the scheme used to make the device yourself, its functionality must be checked. The soldering iron itself must be included in the working circuit. He is a load.

In the designs of thermostats for soldering irons, where LEDs are used in the circuits, this is easy to do. A change in the brightness of the glow indicates that the created design is working. For the rest, the test must be carried out with an incandescent lamp connected to the circuit. If there is a series LED with a resistor in the circuit, the test is carried out using an indicator. If it does not light up, then it is necessary to make an adjustment, i.e. select a resistor.

Note! For soldering irons with a power of 100 W and higher, in the regulator circuits it is necessary to install triacs or thyristors on radiators.

A power regulator, made with your own hands or purchased in a retail chain, will allow you to use the tip heating temperature during the soldering process, which will qualitatively connect the necessary components. This will avoid such troubles as damage to parts or their failure, improve the soldering process and save energy consumption.

Video

The temperature of the soldering iron tip depends on many factors.

• Input network voltage, which is not always stable;
• Heat dissipation in massive wires or contacts on which soldering is performed;
• Ambient air temperatures.

For high-quality work, it is necessary to maintain the thermal power of the soldering iron at a certain level. There is a large selection of electrical appliances with a temperature controller on sale, but the cost of such devices is quite high.

Soldering stations are even more advanced. Such complexes contain a powerful power supply, with which you can control temperature and power over a wide range.

The price matches the functionality.
What should you do if you already have a soldering iron and don’t want to buy a new one with a regulator? The answer is simple - if you know how to use a soldering iron, you can make an addition to it.

DIY soldering iron regulator

This topic has long been mastered by radio amateurs, who are more interested in a high-quality soldering tool than anyone else. We offer you several popular solutions with electrical diagrams and assembly procedures.

Two-stage power regulator

This circuit works on devices powered by an alternating voltage network of 220 volts. A diode and a switch are connected in parallel to each other into the open circuit of one of the supply conductors. When the switch contacts are closed, the soldering iron is powered in standard mode.

When opened, current flows through the diode. If you are familiar with the principle of alternating current flow, the operation of the device will be clear. The diode, passing current in only one direction, cuts off every second half-cycle, reducing the voltage by half. Accordingly, the power of the soldering iron is reduced by half.

Basically, this power mode is used during long pauses during work. The soldering iron is in standby mode and the tip is not very cool. To bring the temperature to 100%, turn on the toggle switch - and after a few seconds you can continue soldering. When the heating decreases, the copper tip oxidizes less, extending the service life of the device.

Dual-mode circuit using a low-power thyristor

This voltage regulator for a soldering iron is suitable for low-power devices, no more than 40 W. For power control, thyristor KU101E is used (VS2 in the diagram). Despite its compact size and lack of forced cooling, it practically does not heat up in any mode.

The thyristor is controlled by a circuit consisting of a variable resistor R4 (a regular SP-04 with a resistance of up to 47K is used) and a capacitor C2 (electrolyte 22MF).

The operating principle is as follows:

• Standby mode. Resistor R4 is not set to the maximum resistance, thyristor VS2 is closed. The soldering iron is powered through a VD4 diode (KD209), reducing the voltage to 110 volts;
• Adjustable operating mode. In the middle position of resistor R4, thyristor VS2 begins to open, partially passing current through itself. The transition to operating mode is controlled using the VD6 indicator, which lights up when the voltage at the regulator output is 150 volts.

IMPORTANT! The test is performed under load, that is, with a soldering iron connected.

When rotating resistor R2, the voltage at the input to the soldering iron should change smoothly. The circuit is placed in the body of the overhead socket, which makes the design very convenient.

IMPORTANT! It is necessary to reliably insulate the components with heat-shrinkable tubing to prevent short circuits in the housing - socket.

The bottom of the socket is covered with a suitable cover. The ideal option is not just an overhead socket, but a sealed street socket. In this case, the first option was chosen.
It turns out to be a kind of extension cord with a power regulator. It is very convenient to use, there are no unnecessary devices on the soldering iron, and the control knob is always at hand.

Microcontroller controller

If you consider yourself an advanced radio amateur, you can assemble a voltage regulator with digital display worthy of the best industrial designs. The design is a full-fledged soldering station with two output voltages - fixed 12 volts and adjustable 0-220 volts.

The low-voltage unit is implemented on a transformer with a rectifier, and is not particularly difficult to manufacture.

IMPORTANT! When making power supplies with different voltage levels, be sure to install sockets that are incompatible with each other. Otherwise, you can damage the low-voltage soldering iron by mistakenly connecting it to the 220 volt output.

The variable voltage control unit is made on the PIC16F628A controller.

Details of the circuit and listing the element base are unnecessary, everything is visible in the diagram. Power control is performed using a triac VT 136 600. Power supply control is implemented using buttons, the number of gradations is 10. The power level from 0 to 9 is shown on the indicator, which is also connected to the controller.

The clock generator supplies pulses to the controller with a frequency of 4 MHz, this is the speed of the control program. Therefore, the controller instantly reacts to changes in the input voltage and stabilizes the output.

The circuit is assembled on a circuit board; such a device cannot be soldered on weight or cardboard.

Double-sided installation.

For convenience, the station can be assembled in a housing for radio crafts, or in any other suitable size.

For safety reasons, 12 and 220 volt sockets are located on different walls of the case. It turned out reliable and safe. Such systems have been tested by many radio amateurs and have proven their performance.

As you can see from the material, you can independently make an adjustable soldering iron with any capabilities and for any budget.

In order to simplify soldering work and improve its quality, a home craftsman or radio amateur may find it useful to have a simple temperature regulator for the soldering iron tip. This is exactly the kind of regulator that the author decided to assemble for himself.

The author first noticed a diagram of such a device in the magazine “Young Technician” in the early 80s. Using these diagrams, the author collected several copies of such regulators and still uses them.

To assemble a device for regulating the temperature of a soldering iron tip, the author needed the following materials:
1) diode 1N4007, although any other one is suitable, for which a current of 1 A and a voltage of 400-60 V are acceptable
2) thyristor KU101G
3) electrolytic capacitor 4.7 uF whose operating voltage is from 50 V to 100 V
4) resistor 27 - 33 kOhm, the power of which is from 0.25 to 0.5 watts
5) variable resistor 30 or 47 kOhm SP-1 with linear characteristic
6) power supply housing
7) a pair of connectors with holes for pins with a diameter of 4 mm

Description of the manufacture of a device for regulating the temperature of a soldering iron tip:

In order to better understand the device diagram, the author drew how the parts are placed and their mutual connection.

Before starting to assemble the device, the author insulated and molded the leads of the parts. Tubes about 20 mm long were put on the terminals of the thyristor, and tubes 5 mm long were put on the terminals of the resistor and diode. To make it more convenient to work with the leads of parts, the author suggested using colored PVC insulation, which can be removed from any suitable wires and then attached with heat shrink. Next, using the given drawing and photographs as a visual aid, you need to carefully bend the conductors without damaging the insulation. Then all the parts are attached to the terminals of the variable resistor, while combining into a circuit that contains four soldering points. The next step is to insert the conductors of each of the device components into the holes on the terminals of the variable resistor and carefully solder them. After which the author shortened the leads of the radio elements.

Then the author connected together the leads of the resistance, the control electrode of the thyristor and the positive wire of the capacitor and fixed them with a soldering iron. Since the thyristor body is an anode, the author decided to insulate it for safety.

To give the design a finished look, the author used a power supply housing with a power plug. To do this, a hole was drilled on the top edge of the case. The hole diameter was 10 mm. The threaded part of the variable resistor was installed into this hole and secured with a nut.

To connect the load, the author used two connectors with holes for pins with a diameter of 4 mm. To do this, the centers of the holes were marked on the body with a distance of 19 mm between them, and connectors were installed into the drilled holes with a diameter of 10 mm, which the author also secured with nuts. Next, the author connected the housing plug to the assembled circuit and the output connectors, and protected the soldering points using heat shrink.

Then the author selected a suitable handle made of insulating material of the desired shape and size in order to cover both the axle and the nut.
Then the author assembled the body and securely fixed the regulator handle.

Then I started testing the device. The author used a 20-40 Watt incandescent lamp as a load for testing the regulator. It is important that when you turn the knob, the brightness of the lamp changes smoothly enough. The author was able to achieve a change in the brightness of the lamp from half to full incandescence. Thus, when working with soft solders, for example POS-61, using an EPSN 25 soldering iron, 75% of the power is enough for the author. In order to obtain such indicators, the regulator handle should be located approximately in the middle of the stroke.