DIY soldering iron with temperature control. DIY power regulator for a soldering iron - diagrams and installation options

In order to obtain high-quality and beautiful soldering, it is necessary to correctly select the power of the soldering iron and ensure a certain temperature of its tip, depending on the brand of solder used. I offer several circuits of homemade thyristor temperature controllers for soldering iron heating, which will successfully replace many industrial ones that are incomparable in price and complexity.

Attention, the following thyristor circuits of temperature controllers are not galvanically isolated from the electrical network and touching the current-carrying elements of the circuit can lead to electric shock!

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.

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.

The classical regulator circuit works as follows. AC mains voltage is supplied through the 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 2-5 V, 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 charging current of capacitor C1 will decrease and it will take more time for the voltage on it to reach 2-5 V, 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.

Above is a classic circuit of a thyristor regulator made on a KU202N thyristor. Since controlling this thyristor requires a larger current (according to the passport 100 mA, the real one is about 20 mA), the values ​​of resistors R1 and R2 are reduced, R3 is eliminated, and the size of the electrolytic capacitor is increased. When repeating the circuit, it may be necessary to increase the value of capacitor C1 to 20 μF.

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 0.1 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.

The circuits can be used for adjustment with a supply voltage of 36 V or 24 V AC. You only 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 W at a voltage of 36 V will consume a current of 1.1 A.

Thyristor circuit of the regulator does not emit interference

The main difference between the circuit of the presented soldering iron power regulator and those presented above is the complete absence of radio interference into the electrical network, since all transient processes occur at a time when the voltage in the supply network is zero.

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.

The temperature controller circuit works as follows. The AC 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 diode VD5, creating a supply voltage of about 9 V for microcircuits DD1 and DD2. R2 performs a protective function, limiting the maximum possible voltage on VD5 and VD6 to 22 V, 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 thyristor temperature controller are placed on a printed circuit board made of fiberglass. Since the circuit does not have galvanic isolation from the electrical network, the board is placed in a small plastic case of a former adapter with an electrical plug. A plastic handle is attached to the axis of the variable resistor R5. Around the handle on the regulator body, for the convenience of regulating the degree of heating of the soldering iron, there is a scale with conventional numbers.

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. The Soviet thyristor KU103V can be replaced, for example, with a modern thyristor MCR100-6 or MCR100-8, designed for a switching current of up to 0.8 A. In this case, it will be possible to control the heating of a soldering iron with a power of up to 150 W. Diodes VD1-VD4 are any, designed for a reverse voltage of at least 300 V and a current of at least 0.5 A. IN4007 (Uob = 1000 V, I = 1 A) is perfect. Any pulse diodes VD5 and VD7. Any low-power zener diode VD6 with a stabilization voltage of about 9 V. Capacitors of any type. Any resistors, R1 with a power of 0.5 W.

The power regulator does not need to be adjusted. If the parts are in good condition and there are no installation errors, it will work immediately.

The circuit was developed many years ago, when computers and especially laser printers did not exist in nature, and therefore I made a drawing of the printed circuit board using old-fashioned technology on chart paper with a grid pitch of 2.5 mm. Then the drawing was glued with Moment glue onto thick paper, and the paper itself was glued to foil fiberglass. Next, holes were drilled on a homemade drilling machine and the paths of future conductors and contact pads for soldering parts were drawn by hand.

The drawing of the thyristor temperature controller has been preserved. Here is his photo. Initially, the rectifier diode bridge VD1-VD4 was made on a KTs407 microassembly, but after the microassembly was torn twice, it was replaced with four KD209 diodes.

How to reduce the level of interference from thyristor regulators

To reduce interference emitted by thyristor power regulators into the electrical network, ferrite filters are used, which are a ferrite ring with wound turns of wire. Such ferrite filters can be found in all switching power supplies for computers, televisions and other products. An effective, noise-suppressing ferrite filter can be retrofitted to any thyristor regulator. It is enough to pass the wire connecting to the electrical network through the ferrite ring.

The ferrite filter must be installed as close as possible to the source of interference, that is, to the installation site of the thyristor. The ferrite filter can be placed both inside the device body and on its outside. The more turns, the better the ferrite filter will suppress interference, but simply threading the power cable through the ring is sufficient.

The ferrite ring can be taken from the interface wires of computer equipment, monitors, printers, scanners. If you pay attention to the wire connecting the computer system unit to the monitor or printer, you will notice a cylindrical thickening of insulation on the wire. In this place there is a ferrite filter for high-frequency interference.

It is enough to cut the plastic insulation with a knife and remove the ferrite ring. Surely you or someone you know has an unnecessary interface cable from an inkjet printer or an old CRT monitor.

It has long been known that when a soldering iron overheats, the tip becomes covered with oxides and quickly burns out, especially in cheap Chinese ones. Therefore, we will assemble a good power regulator circuit that will control the degree of its heating.

The main element of the circuit is a powerful triac (symmetrical thyristor). It works the same as a thyristor, but does not have an anode and a cathode; current can flow in both directions. The triac is controlled by a symmetrical dinistor or diac, in this case DB3 (Soviet analogue of KN 102).

A dinistor can be found in the ballast of an economy lamp, in an electronic transformer, or bought (costs pennies). A dinistor can be conditionally called a spark gap. It has a certain breakdown voltage and will open only when this value is reached.

According to the datasheet on DB3, this is an average of 28-30V. At each half-wave of the mains voltage, capacitor C1 is charged through R1 and R2. When the voltage reaches the breakdown value of the dinistor, it will open and voltage will flow to the control electrode of the triac. The triac will work (open), the current will flow through the load.

The chain VD1, VD2, C2, R3 is designed for normal operation of the thyristor at minimum output power. The operating principle of all similar circuits is the same: the longer the delay time for turning on the thyristor, the lower the output power.

This circuit is distinguished by the fact that it operates stably at any output power. By replacing only the thyristor with a more powerful one, you can get a regulator capable of switching a load of tens of kilowatts. For example, last winter I used it with a 5 kW heater. If the regulator is used for a soldering iron, then you can do without a heat sink. In case of powerful loads, you will need an appropriate radiator.

The printed circuit board is compact and can fit in a matchbox; you can even assemble the regulator in the handle of a soldering iron. I assembled it in a small package. By the way, many Chinese industrial soldering irons supplemented with such a simple regulator are advertised as a “soldering station”.

List of components

• You can buy a ready-made power regulator
• You can buy a triac
• You can buy 30pcs dinistor for $0.85
• You can buy 100pcs 1n4007 diodes for $0.75

For many experienced radio amateurs, making a power regulator for a soldering iron with your own hands is quite common. For beginners, due to lack of experience, such designs pose a certain difficulty. The main problem is connecting to a 220 V power supply. If there are errors in the circuit or installation, a rather unpleasant effect can occur, accompanied by a loud sound and a power cut. Therefore, in the absence of experience, it is advisable to first purchase a simple device for adjusting power, and after using it and studying it, based on the experience gained, make your own, more advanced one.

An electric soldering iron is a hand-held tool designed to melt solder and heat the parts being joined to the desired temperature.

To prevent emergency situations, a circuit breaker with a small maximum permissible current and one or two sockets should be installed in the workplace. Sockets should be used for the initial connection of manufactured devices. This security measure will allow you to avoid a general shutdown and trips to the control panel, as well as sarcastic comments from family members.

Step power regulator

To manufacture a control device you need to select:

• a 220 V transformer with a power exceeding the power of the soldering iron by 20-25% (the voltage on the secondary winding must be at least 200 V);
• switch for 3-4 positions, more possible. The maximum permissible current of the contacts must correspond to the current consumption of the soldering iron;
• body of the required size;
• cord with plug;
• socket.

You will also need fasteners, screws, screws with nuts. The secondary winding should be rewound, setting the terminals to voltage from 150 to 220 V. The number of terminals will depend on the type of switch; it is desirable to distribute the voltage at the terminals evenly. A switch and voltage indicator can be installed in the power circuit to indicate on/off status.

The device works as follows. If there is power on the primary winding, a voltage of the appropriate magnitude is generated on the secondary winding. Depending on the position of switch S1, the soldering iron will receive voltage from 150 to 220 V. By changing the position of the switch, you can change the heating temperature. If the parts are available, even a beginner can make such a device.

Regulator with smooth power adjustment

This circuit allows you to assemble a compact, small-sized regulator with smooth adjustment of power consumption. The device can be mounted in a socket or in the housing of a mobile phone charger. The device can operate with a load of up to 500 W. For production you will need:

• thyristor KU208G or its analogues;
• diode KR1125KP2, can be replaced with similar diodes;
• a capacitor with a capacity of 0.1 μF with a voltage of at least 160 V;
• resistor 10 kOhm;
• variable resistor 470 kOhm.

The device is quite simple; if there are no assembly errors, it starts working immediately, without additional adjustment. It is advisable to include a voltage indicator and a fuse in the power circuit. The power consumption of the soldering iron is regulated by a variable resistor. A transformer of the required power can be used to regulate the heating temperature of the soldering iron. The best option is to use a device called “LATR”, but such devices have long been discontinued. In addition, they have significant weight and dimensions; they can only be used permanently.

Regulator with temperature control

The device is a thermostat that turns off the load when a specified parameter is reached. The measuring element should be secured to the soldering iron tip. To connect, you need to use a wire in heat-resistant insulation, connect them to a common connector for connecting a soldering iron. You can use separate connections, but this is inconvenient.

Temperature control is carried out by a thermistor KMT-4 or another with similar parameters. The principle of operation is quite simple. Thermal resistance and control resistor are a voltage divider. The variable resistance sets a certain potential at the midpoint of the divider. When heated, the thermistor changes its resistance and, accordingly, changes the set voltage. Depending on the signal level, the microcircuit outputs a control signal to the transistor.

The low-voltage circuit is powered through a limiting resistor and is maintained at the required level by a zener diode and a smoothing electrolytic capacitor. The transistor opens or closes the thyristor with the emitter current. The soldering iron is connected in series with the thyristor.

The maximum permissible power of the soldering iron is no more than 200 W. If you need to use a more powerful soldering iron, you need to use diodes with a higher maximum permissible current for the rectifier bridge, instead of a thyristor - a trinistor. All power elements of the circuit must be installed on heat-removing radiators made of aluminum or copper. The required size for a power of 2 kW for rectifier bridge diodes is at least 70 cm 2, for a trinistor 300 cm 2.

Regulator for a soldering iron on a triac

The most optimal circuit for adjusting the power of a soldering iron is a triac regulator. The soldering iron is connected in series with the triac. All controls operate on the voltage drop of the power control element. The circuit is quite simple and can be performed by radio amateurs with little experience. The value of the control resistor can be changed depending on the required range at the regulator output. With a value of 100 kOhm, you can change the voltage from 160 to 220 V, at 220 kOhm - from 90 to 220 V. At the maximum operating mode of the regulator, the voltage on the soldering iron differs from the mains voltage by 2-3 V, which distinguishes it for the better from devices with thyristors. The voltage change is smooth, you can set any value. The LED in the circuit is intended to stabilize operation, and not as an indicator. It is not recommended to replace or exclude it from the scheme. The device begins to work unstably. If necessary, you can install an additional LED as a voltage indicator with appropriate limiting elements.

For installation, you can use a regular installation box. Installation can be done using a hinged method or a board can be made. To connect a soldering iron, it is advisable to install a socket at the output of the regulator.

When installing a switch in the input circuit, you must use a device with two pairs of contacts that will disconnect both wires. Manufacturing the device does not require significant material costs and can be done quite simply by novice radio amateurs. Adjustment during operation consists of selecting the optimal voltage range for the operation of the soldering iron. This is done by selecting the value of the variable resistor.

The simplest regulator circuit

The simplest temperature controller for a soldering iron can be assembled from a diode with a maximum forward current corresponding to the power of the soldering iron and the switch. The circuit is assembled very simply - the diode is connected in parallel with the contacts of the switch. Operating principle: when the contacts are open, the soldering iron receives only half-cycles of one polarity, the voltage will be 110 V. The soldering iron will have a low temperature. When the contacts are closed, the soldering iron will receive full mains voltage rated at 220 V. The soldering iron will warm up to maximum temperature in a few seconds. This scheme will protect the tool tip from overheating and oxidation and will help significantly reduce energy consumption.

The design can be anything. You can use a manual switch or install a switch with a lever system on a stand. When the tool is lowered onto the stand, the switch should open its contacts, and when raised, close it.

Conclusion on the topic

For complex work, it is desirable to have an optimal, reliable tool that does not create unnecessary problems during work.

Industrial designs, although of good quality and functionality, are quite expensive for beginners.

Manufacturing various devices and fixtures will greatly facilitate the work and help you gain the necessary experience.

A soldering iron with temperature control is a power tool necessary for soldering various radio components subject to overheating (transistors, resistors, capacitors, microcircuits, diodes). It is used not only by beginners and experienced radio amateurs, home craftsmen, but also by specialists involved in the repair of electronic devices. The significantly increased popularity of such power tools in recent years is explained by its many advantages and the ability to assemble it yourself.

Design

The simplest instrument of this type with thermoregulation consists of the following parts:

• Housing with a printed circuit board inside - cylindrical hollow handle made of dense plastic
• Control board – controller located inside the hollow handle;
• Regulator – a resistor with variable resistance, having a rotating round knob indicating temperature values;
• LED – indicator indicating that the tip has heated up to the set temperature;
• Retaining tube with nut - a fitting with a tip inserted inside it and a movable nut, with which it is screwed to the body;
• The heating element is a tube on which the tip is placed;
• Fireproof tip – a pre-tinned conical tip with a heat-resistant fireproof coating.

In many modern models of this power tool, the regulator is made in the form of two buttons; the temperature value is indicated on a small monochrome liquid crystal display.

Why increase power?

An increase in power and, therefore, temperature is necessary in order to solder radio components of different temperature resistance and sizes. Thus, for soldering small thyristors of small-capacity capacitors, a much lower temperature is required than for their larger counterparts.

Principle of operation

Heating and maintaining the set temperature of the tip of such an adjustable soldering iron occurs as follows:

1. When the device is connected to a power source, current flows to the regulator;
2. By changing the resistance of the regulator, a certain power level of the heating element is established, which corresponds to the tip temperature pre-calculated and set during testing of the tool;
3. Maintaining a strictly defined temperature of the tip occurs thanks to a temperature sensor located inside it - a small thermocouple that prevents overheating of the tip.

Thanks to the presence of a heating control board and a temperature sensor, overheating and overheating of radio components that are very sensitive to elevated temperatures are eliminated when working with such a tool. In addition, unlike unregulated analogues, such tools are completely protected from phase breakdown on the tip.

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

Such a soldering iron is a mains-powered device that lowers the mains voltage but increases 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

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.

Advantages and disadvantages

A soldering iron with a temperature controller has a number of pros and cons.

The advantages of such a tool include:

• Possibility of temperature adjustment;
• Complete elimination of the risk of overheating and damage to high-temperature sensitive radio components;
• Fast heating;
• Affordable price;
• The device comes with a set of fireproof tips - pre-tinned tips with a special non-burning coating.

The disadvantages of such devices include:

• Low maintainability;
• High cost of high-quality semi-professional and professional models;
• Fragility of the ceramic heating element.

Another disadvantage of cheap models is a fake ceramic heater, which is a hollow ceramic tube, inside of which there is an asbestos rod with a thin nichrome wire wound around it. Due to the small thickness of the wire, such heaters very quickly fail due to thermostriction - rupture of the wire when it cools.

Heating control

To control heating in such devices, an analog or digital (push-button) thermostat, a temperature sensor in the heating element and a control board are used. In some models and improved simple soldering irons, temperature control occurs thanks to two-position switches, dimmers, and electronic control units.

Switches and Dimmers

To adjust the temperature of the soldering iron tip, devices such as:

• Switches – two-position toggle switches that allow you to switch the instrument to standby or maximum heating mode;
• Dimmers are regulators connected to a wire break with a round, smoothly rotating knob, allowing very fine adjustment of the degree of heating of the tip.

Control units

The control unit is a control board located separately from the device with an adjusting resistor. Some control units also have a step-down transformer built into them.

The most advanced and multifunctional control units, together with soldering irons connected to them, constitute a type of device called soldering stations.

Self-production of power regulators for soldering irons

You can not only purchase a power regulator for a soldering iron, but also quite easily assemble it yourself. It is mounted into a break in the network cable of devices in housings from small old electrical appliances. For soldering circuits, perforated textolite boards with copper coating are used.

Below are diagrams of the most commonly assembled thermostats based on radio components such as a variable resistor, triac, and thyristor.

From a resistor

The simplest thermostat for a soldering iron based on a variable resistor is assembled according to the diagram below.

From a thyristor

The thyristor-based thermostat board has the following circuit diagram.

From a triac

The simplest thermostat using semiconductor parts such as triacs can be assembled according to the following scheme.

Regulator circuits

The regulator for a soldering iron can be assembled according to two schemes: dimmer and step.

Dimmer room

The dimmer circuit includes one regulator (dimmer) connected to the break in the device’s network cable.

Stepped

A do-it-yourself power regulator for a soldering iron using a stepwise design involves installing an additional controller in a plastic case.

Video

At 12 volts/8 watts, but the price was somewhat unusual, only 80 rubles versus 120, as in other retail outlets. I was planning to do something similar myself, but then chance deprived me of such an opportunity. The seller assured that it was in working order and even checked it by connecting it to the power supply. I came home and started trying it out. Stabilized UPS just for its voltage. Everything seems to be fine, the tin is melting, just a little slower than usual. In the end, I figured out why the price was too low and why the work was “slow.” It turned out that the soldering iron needs not 12 volts for normal operation, but a little more. I remembered the cheese in the mousetrap, although of course this case is a little different. To fully operate the soldering iron, I decided to assemble a simple voltage regulator and power it from a 17-volt power supply.

Regulator circuit

The scheme is simple “to the point of indecentness” (which is why it was even subjected to severe criticism on one of the related sites) and should, no, simply must work.

However, I did some preliminary assembly. Within an hour, everything was fully mounted on an improvised circuit board. Both components and installation. Immediately the opportunity arose for full-time work with a soldering iron.

To test the assembled device, to fully understand the result obtained, I used a voltmeter and an ammeter. Observing changes in specific current and voltage values ​​will always help you be objective about the result of your efforts.

Video

Output voltage up to 16 volts, maximum current consumption up to 500 mA. As a result of the manipulations performed, I came to the conclusion that the transistor should be installed more powerful. For example KT829A. You never know where I’ll think of connecting a ready-made regulator and what to power through it. This regulator does not provide a stabilized output voltage; a slight increase, albeit a very slow one, was noticed. And since I plan to do soldering for a short time, this is not an obstacle.

I used the temporary assembly several times over the course of a week, and it worked well. It's time to give the device a more or less “human” appearance. I assembled the components: the case, a metal roller for its stability, a soldering iron holder and a connecting screw.

Since I decided to use the roller as an additional radiator, I isolated it from the soldering iron holder using a plastic washer.

After placing the main components, I installed RGB sockets at the input and output (the voltage and current are not large), this will avoid installing permanent wires (which always get tangled). And use ready-made, fully equipped ones. There have been plenty of them since the days of VCRs.

The main components are a transistor and two resistors, but there are still enough wires.

This is what happened. It is no coincidence that the LED is connected to the output of the regulator - with a change in the output voltage, the brightness of its glow changes, and quite significantly. I did not equip the regulator with something like a scale - there were quite a sufficient number of marks left on the body around from its previous purpose. This is how, thanks to the diagram seen on the site’s forum, it was possible to solve the issue of powering a low-voltage soldering iron with a non-standard supply voltage. I assembled it Babay iz Barnaula.

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