The main regulating element of many circuits is a thyristor or triac. Let's look at several circuits built on this element base.
Option 1.
Below is the first diagram of the regulator, as you can see it probably couldn’t be simpler. The diode bridge is assembled using D226 diodes; a KU202N thyristor with its own control circuits is included in the diagonal of the bridge.
Here is another similar scheme that can be found on the Internet, but we will not dwell on it.
To indicate the presence of voltage, you can supplement the regulator with an LED, the connection of which is shown in the following figure.
You can install a switch in front of the power supply diode bridge. If you use a toggle switch as a switch, make sure that its contacts can withstand the load current.
Option 2.
This regulator is built on a VTA 16-600 triac. The difference from the previous version is that there is a neon lamp in the circuit of the control electrode of the triac. If you choose this regulator, then you will need to choose a neon with a low breakdown voltage, the smoothness of the soldering iron power adjustment will depend on this. A neon light bulb can be cut out of a starter used in LDS lamps. Capacity C1 is ceramic at U=400V. Resistor R4 in the diagram indicates the load, which we will regulate.
The operation of the regulator was checked using a regular table lamp, see photo below.
If you use this regulator for a soldering iron with a power not exceeding 100 W, then the triac does not need to be installed on the radiator.
Option 3.
This circuit is a little more complicated than the previous ones; it contains a logic element (counter K561IE8), the use of which allowed the regulator to have 9 fixed positions, i.e. 9 stages of regulation. The load is also controlled by a thyristor. After the diode bridge there is a conventional parametric stabilizer, from which the power for the microcircuit is taken. Choose diodes for the rectifier bridge such that their power matches the load that you will regulate.
The device diagram is shown in the figure below:
Reference material for the K561IE8 chip:
Diagram of operation of the K561IE8 chip:
Option 4.
Well, the last option, which we will now consider, is how to make a soldering station yourself with the function of regulating the power of the soldering iron.
The circuit is quite common, not complicated, repeated many times by many, no scarce parts, supplemented by an LED that shows whether the regulator is on or off, and a visual control unit for the installed power. Output voltage from 130 to 220 volts.
This is what the assembled regulator board looks like:
The modified printed circuit board looks like this:
The M68501 head was used as an indicator; these used to be used in tape recorders. It was decided to modify the head a little; an LED was installed in the upper right corner, it will show whether it is on/off, and will highlight the small-to-small scale.
The matter was left to the body. It was decided to make it from plastic (foamed polystyrene), which is used for making all kinds of advertisements; it is easy to cut, well processed, glued tightly, and the paint lays down evenly. We cut out the blanks, clean the edges, and glue them with “cosmofen” (glue for plastic).
Many years ago, I made a similar regulator when I had to earn extra money repairing radios at a customer’s home. The regulator turned out to be so convenient that over time I made another copy, since the first sample was constantly installed as an exhaust fan speed regulator. https://site/
By the way, this fan is from the Know How series, as it is equipped with an air shut-off valve of my own design. The material may be useful for residents living on the top floors of high-rise buildings and who have a good sense of smell.
The power of the connected load depends on the thyristor used and its cooling conditions. If a large thyristor or triac of the KU208G type is used, then you can safely connect a load of 200 ... 300 Watts. When using a small thyristor, type B169D, the power will be limited to 100 Watts.
This is how a thyristor works in an alternating current circuit. When the current flowing through the control electrode reaches a certain threshold value, the thyristor is unlocked and locked only when the voltage at its anode disappears.
A triac (symmetrical thyristor) works in approximately the same way, only when the polarity at the anode changes, the polarity of the control voltage also changes.
The picture shows what goes where and where it comes out.
In budget control circuits for KU208G triacs, when there is only one power source, it is better to control the “minus” relative to the cathode.
To check the functionality of the triac, you can assemble such a simple circuit. When the button contacts close, the lamp should go out. If it does not go out, then either the triac is broken or its threshold breakdown voltage is below the peak value of the network voltage. If the lamp does not light when the button is pressed, then the triac is broken. The resistance value R1 is selected so as not to exceed the maximum permissible value of the control electrode current.
When testing thyristors, a diode must be added to the circuit to prevent reverse voltage.
A simple power regulator can be assembled using a triac or thyristor. I will tell you about those and other circuit solutions.
VS1 – KU208G
HL1 – MH3... MH13, etc.
This diagram shows, in my opinion, the simplest and most successful version of the regulator, the control element of which is the KU208G triac. This regulator controls the power from zero to maximum.
HL1 – linearizes control and is an indicator.
C1 – generates a sawtooth pulse and protects the control circuit from interference.
R1 – power regulator.
R2 – limits the current through the anode - cathode of VS1 and R1.
R3 – limits the current through HL1 and the control electrode VS1.
VS1 – KU202N
A similar circuit can be assembled using the KU202N thyristor. Its difference from the triac circuit is that the regulator power adjustment range is 50... 100%.
The diagram shows that the limitation occurs only along one half-wave, while the other passes unhindered through the diode VD1 into the load.
This circuit, assembled on the cheapest low-power thyristor B169D, differs from the circuit given above only by the presence of resistor R5, which, together with resistor R4, acts as a voltage divider and reduces the amplitude of the control signal. The need for this is caused by the high sensitivity of low-power thyristors. The regulator regulates power in the range of 50... 100%.
VD1... VD4 – 1N4007
In order for the thyristor regulator to control power from zero to 100%, you need to add a diode bridge to the circuit.
Now the circuit works similarly to a triac regulator.
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.
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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.
Pinout (pinout) of large domestic triacs and thyristors. Thanks to the powerful metal body, these devices can dissipate power of 1… 2 Watts without a significant change in parameters without an additional radiator.
Pinout of small popular thyristors that can control the network voltage at an average current of 0.5 Amperes.
| Device type | Cathode | Manager | Anode |
| BT169D(E, G) | 1 | 2 | 3 |
| CR02AM-8 | 3 | 1 | 2 |
| MCR100-6(8) | 1 | 2 | 3 |
For decent quality soldering work, a home craftsman, and even more so a radio amateur, will need a simple and convenient soldering iron tip temperature regulator. For the first time I saw a diagram of the device in the magazine “Young Technician” in the early 80s, and having collected several copies, I still use it.
To assemble the device you will need:
- diode 1N4007 or any other, with a permissible current of 1A and a voltage of 400 - 600V.
-thyristor KU101G.
-electrolytic capacitor 4.7 microfarads with an operating voltage of 50 - 100V.
-resistance 27 - 33 kilo-ohms with permissible power 0.25 - 0.5 watts.
-variable resistor 30 or 47 kilo-ohm SP-1, with linear characteristic.
For simplicity and clarity, I drew the placement and interconnection of parts.
Before assembly, it is necessary to insulate and mold the leads of the parts. We put 20mm long insulating tubes on the thyristor terminals, and 5mm long on the diode and resistor terminals. For clarity, you can use colored PVC insulation removed from suitable wires, or apply heat shrink. Trying not to damage the insulation, we bend the conductors, guided by the drawing and photographs.
All parts are mounted on the terminals of a variable resistor, connected into a circuit with four soldering points. We insert the component conductors into the holes on the terminals of the variable resistor, trim everything and solder it. We shorten the leads of the radio elements. The positive terminal of the capacitor, the control electrode of the thyristor, the resistance terminal, are connected together and fixed by soldering. The thyristor body is the anode; for safety, we insulate it.
To give the design a finished look, it is convenient to use a housing from a power supply with a power plug.
On the top edge of the case we drill a hole with a diameter of 10 mm. We insert the threaded part of the variable resistor into the hole and secure it with a nut.
To connect the load, I used two connectors with holes for pins with a diameter of 4 mm. On the body we mark the centers of the holes, with a distance between them of 19 mm. In drilled holes with a diameter of 10 mm. insert the connectors and secure with nuts. We connect the plug on the case, the output connectors and the assembled circuit; the soldering points can be protected with heat shrink. For a variable resistor, it is necessary to select a handle made of insulating material of such shape and size as to cover the axle and nut. We assemble the body and securely fix the regulator handle.
We check the regulator by connecting a 20 - 40 watt incandescent lamp as a load. By rotating the knob, we make sure that the brightness of the lamp changes smoothly, from half brightness to full intensity.
When working with soft solders (for example POS-61), with an EPSN 25 soldering iron, 75% of the power is sufficient (the position of the control knob is approximately in the middle of the stroke). Important: all elements of the circuit have a supply voltage of 220 volts! Electrical safety precautions must be observed.
REGULATOR FOR SOLDERING IRON
Surely, among those starting out in electronics, there are owners of medium and high power soldering irons. In this case, I mean, of course, the power of a soldering iron for soldering electronics. Moreover, sometimes these are not grandfather’s monsters, with a sting as thick as a little finger, but quite neat 40-watt EPSN. With such soldering irons, if you sharpen the tip to a sharp cone, it is quite convenient to solder transistors, resistors and other output parts, and if necessary, you can even perform one-time work on soldering SMD parts. If not for one thing. With such soldering irons, even if their power is only forty watts, the temperature of the tip is quite high, and when soldering, there is a high probability of overheating the semiconductor parts.
In this case, there is no need to buy a new soldering iron with a power of 25 watts; it is enough to assemble a power regulator using a thyristor or triac. For personal use, I have a power regulator based on the KU201L thyristor. The circuit works flawlessly for many years, and allows you to adjust the power from half to maximum. Today an acquaintance contacted me who was interested in radio engineering and had just such a soldering iron. It was decided to help the person, and so that the desire to work in electronics would not be lost due to financial barriers, I agreed to assemble a power regulator. The necessary parts were purchased, costing only about 70 rubles, and assembly began. The assembly itself is so elementary that anyone who knows how to distinguish a triac from a resistor can solder this regulator. I assembled everything using a hinged installation, connecting the parts by twisting, followed by soldering the connections.
Below is a diagram of the regulator:
There are similar circuits based on both thyristors and triacs. I settled on this circuit because in it, unlike the one I assembled earlier, the power is regulated to zero, and not to half. The friend also expressed the wish that the device, if necessary, could be used to adjust the brightness of incandescent lamps. Below is a list of parts needed for assembly:
Let's look at them in more detail:
First of all, we need a triac capable of regulating power up to 300 Watts, so that there is a power reserve, and an operating voltage of 400 volts and higher. The pinout of the triac can be seen in the figure below:
For beginners who have not encountered triacs before, I will give its equivalent circuit:
In other words, here we see 2 back-to-back thyristors installed in parallel, with a common control electrode. The triac must be attached to the radiator by applying thermal paste. I usually use the domestic KPT-8.
This radiator area will be enough for long-term operation of the triac, even with significant load power, without worrying about its overheating.
The LED lights up when the device is operating. Any voltage of 2.5 - 3 volts will do. Using a variable resistor motor, we adjust the power from zero to maximum. The top terminal of the variable resistor in the diagram will be the leftmost terminal of the resistor if you turn it with its front side facing you. The left and middle terminals of the variable resistor must be connected with a jumper. A variable resistor is suitable with a resistance of 470 - 500 KiloOhm, with a linear dependence. Let me remind you that for domestic resistors, the marking should be the letter A, for imported ones the letter B (English B).
The circuit needs a diode designed for a reverse voltage of 400 - 1000 volts, 1 ampere. The capacitor is ceramic, designed to operate at voltages up to 50 volts. The circuit also uses a DB3 dinistor. You need a resistor of the MLT type, or a similar imported one, with a power of 0.25 Watt.
The dinistor has no polarity. Sometimes a dinistor is also called a four-layer diode. Below is its equivalent circuit:
The entire assembly of the regulator took me less than an hour. Pieces of mounting wire were cut, the leads of the parts were extended, twisted and reliably soldered. A device made by surface mounting is no less reliable and durable during operation than one made on a printed circuit board, if the installation itself is carried out conscientiously. This is what the device looked like after soldering:
All exposed leads of the parts were insulated with electrical tape and adhesive tape, in several layers. I left the design of the case to the customer, because of taste and color, as they say. All that remains is to connect the socket, the cord with plug and the device can be used. To test the regulator, I applied 220 volts to its input, connecting it with a wire to a plug, and to the crocodiles at the other end. A 200-watt lamp was also connected to the output of the regulator using crocodiles. The adjustment was smooth and I was quite happy with it. In five minutes of operation, the thyristor did not have time to heat up, which suggests that the radiator I used will be more than enough to work together with a soldering iron. Author AKV.
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Build a simple power regulator for a soldering iron in an hour
This article is about how to assemble the simplest power regulator for a soldering iron or other similar load. http://oldoctober.com/
The circuit of such a regulator can be placed in a power plug or in the housing of a burnt out or unnecessary small-sized power supply. It will take an hour or two to assemble the device.
Many years ago, I made a similar regulator when I had to earn extra money repairing radios at a customer’s home. The regulator turned out to be so convenient that over time I made another copy, since the first sample was constantly installed as an exhaust fan speed regulator. http://oldoctober.com/
By the way, this fan is from the Know How series, as it is equipped with an air shut-off valve of my own design. Description of the design >>> The material can be useful for residents living on the top floors of high-rise buildings and who have a good sense of smell.
The power of the connected load depends on the thyristor used and its cooling conditions. If a large thyristor or triac of the KU208G type is used, then you can safely connect a load of 200 ... 300 Watts. When using a small thyristor, type B169D, the power will be limited to 100 Watts.
This is how a thyristor works in an alternating current circuit. When the current flowing through the control electrode reaches a certain threshold value, the thyristor is unlocked and locked only when the voltage at its anode disappears.
A triac (symmetrical thyristor) works in approximately the same way, only when the polarity at the anode changes, the polarity of the control voltage also changes.
The picture shows what goes where and where it comes out.
In budget control circuits for KU208G triacs, when there is only one power source, it is better to control the “minus” relative to the cathode.
To check the functionality of the triac, you can assemble such a simple circuit. When the button contacts close, the lamp should go out. If it does not go out, then either the triac is broken or its threshold breakdown voltage is below the peak value of the network voltage. If the lamp does not light when the button is pressed, then the triac is broken. The resistance value R1 is selected so as not to exceed the maximum permissible value of the control electrode current.
When testing thyristors, a diode must be added to the circuit to prevent reverse voltage.
A simple power regulator can be assembled using a triac or thyristor. I will tell you about those and other circuit solutions.
HL1 – MH3... MH13, etc.
This diagram shows, in my opinion, the simplest and most successful version of the regulator, the control element of which is the KU208G triac. This regulator controls the power from zero to maximum.
HL1 – linearizes control and is an indicator.
C1 – generates a sawtooth pulse and protects the control circuit from interference.
R1 – power regulator.
R2 – limits the current through the anode - cathode VS1 and R1.
R3 – limits the current through HL1 and the control electrode VS1.
A similar circuit can be assembled using the KU202N thyristor. Its difference from the triac circuit is that the regulator power adjustment range is 50... 100%.
The diagram shows that the limitation occurs only along one half-wave, while the other passes unhindered through the diode VD1 into the load.
This circuit, assembled on the cheapest low-power thyristor B169D, differs from the circuit given above only by the presence of resistor R5, which, together with resistor R4, acts as a voltage divider and reduces the amplitude of the control signal. The need for this is caused by the high sensitivity of low-power thyristors. The regulator regulates power in the range of 50... 100%.
VD1. VD4 – 1N4007
In order for the thyristor regulator to control power from zero to 100%, you need to add a diode bridge to the circuit.
Now the circuit works similarly to a triac regulator.
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.
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.
Pinout (pinout) of large domestic triacs and thyristors. Thanks to the powerful metal body, these devices can dissipate power of 1… 2 Watts without a significant change in parameters without an additional radiator.
Pinout of small popular thyristors that can control the network voltage at an average current of 0.5 Amperes.
admin October 9th, 2011 at 21:38
Look at the instructions for this soldering iron.
Most likely, you have a soldering iron with a thermostat. The basis of such soldering irons and not only soldering irons are solid-state volumetric heating elements with a nonlinear characteristic.
The resistance of such an element depends on temperature. When a certain temperature is reached, the resistance of the element begins to increase and the temperature stabilizes.
Structurally, such an element usually has the shape of a bar or cylinder, into which the leads are either pressed or tightly pressed with special springs. A known problem with such elements is contact failure.
I have often seen how such thermistors first began to spark under the influence of mains voltage and only then warmed up. If this is so, then it is quite possible that he does not have very long to live.
You can try tapping your finger on something hard. If this is reflected in the measured resistance, then there is a solid-state heater. If not, then perhaps there is a primitive thermostat on the active element, which is located in the handle.
Of course, all these are assumptions, since I did not hold your soldering iron in my hands.
Why does a soldering iron based on a solid-state nonlinear element or an active regulator not work in this circuit?
To unlock a thyristor or triac, a certain minimum current is required, called holding current. For KU208N, this is 150mA. And although in real triacs this current may be two to three times less, still 5 mOhm cannot create a current even close in value.
Try connecting a soldering iron parallel to a 40-60 watt incandescent light bulb. I'm asking you for the third time. If it doesn’t work, turn the soldering iron plug over (in case of an active thermostat). Well, really, you don’t have a tee at home.
If there is a solid-state element (thermistor), then controlling the temperature of such a soldering iron using a triac regulator will be more difficult than with a conventional soldering iron with a heater on a nichrome spiral (the range will narrow). Although, it should still work. If there is another active regulator inside, then it is unpredictable.
Alexey October 10th, 2011 at 13:47
I wrote that it works parallel to the lamp (in the sense that the lighting of the lamp is regulated). I can’t measure the power on a soldering iron (or current/voltage) yet; later I’ll put together a design to measure arbitrary current formats =) Works in any position of the plug.
In general, I’ll work, if I see any changes in power, then everything will be fine, and I’ll write, if not, I’ll take another soldering iron and try with it. =)
Alexander November 11th, 2011 at 23:00
Please tell me, is it possible in the diagram “Power regulator on a thyristor with an adjustment range of 0... 100%.” Should I use KU202N instead of BT169D? And what power should the resistors be used for? What voltage should the condenser be at?
admin November 11th, 2011 at 23:16
No, you need to do exactly the opposite. You need to add a bridge rectifier to the circuit based on the KU202N thyristor. If you can’t figure out how to do it yourself, then tomorrow I’ll draw a diagram. Today I published an article - I’m tired.
Any resistors from 0.25 Watt and above. Potentiometer 0.5 Watt or higher. The capacitor is 400 Volt, but if not, then a lower voltage one can be used. This scheme is one of those that no matter how you assemble it, you will still end up with a “Kalashnikov”.
Alexander November 12th, 2011 at 16:04
Thanks for the answer. I know how to assemble the bridge, I’ll only install 1N4007 diodes, there are no others, and I’m not going to connect a soldering iron with more than 60 W for now.
Schemes of simple regulators for a soldering iron.
The main regulating element of many circuits is a thyristor or triac. Let's look at several circuits built on this element base.
Below is the first diagram of the regulator, as you can see it probably couldn’t be simpler. The diode bridge is assembled using D226 diodes; a KU202N thyristor with its own control circuits is included in the diagonal of the bridge.
Soldering iron power regulator circuit diagram for KU202N
Here is another similar scheme that can be found on the Internet, but we will not dwell on it.
To indicate the presence of voltage, you can supplement the regulator with an LED, the connection of which is shown in the following figure.
Connecting the LED to a 220 volt network
You can install a switch in front of the power supply diode bridge. If you use a toggle switch as a switch, make sure that its contacts can withstand the load current.
This regulator is built on a VTA 16-600 triac. The difference from the previous version is that there is a neon lamp in the circuit of the control electrode of the triac. If you choose this regulator, then you will need to choose a neon with a low breakdown voltage, the smoothness of the soldering iron power adjustment will depend on this. A neon light bulb can be cut out of a starter used in LDS lamps. Capacity C1 is ceramic at U=400V. Resistor R4 in the diagram indicates the load, which we will regulate.
The operation of the regulator was checked using a regular table lamp, see photo below.
Checking the operation of the power regulator with a table lamp
If you use this regulator for a soldering iron with a power not exceeding 100 W, then the triac does not need to be installed on the radiator.
This circuit is a little more complicated than the previous ones; it contains a logic element (counter K561IE8), the use of which allowed the regulator to have 9 fixed positions, i.e. 9 stages of regulation. The load is also controlled by a thyristor. After the diode bridge there is a conventional parametric stabilizer, from which the power for the microcircuit is taken. Choose diodes for the rectifier bridge such that their power matches the load that you will regulate.
The device diagram is shown in the figure below:
Soldering iron power regulator circuit using a thyristor and K561IE8 microcircuit
Reference material for the K561IE8 chip:
Conclusions of the K561IE8 chip
Table of functioning of the K561IE8 chip:
Diagram of operation of the K561IE8 chip:
Diagram of operation of the K561IE8 chip
Well, the last option, which we will now consider, is how to make a soldering station yourself with the function of regulating the power of the soldering iron. This diagram was taken from the website of Vladimir Boldyrev. www.fototank.ru
The circuit is quite common, not complicated, repeated many times by many, no scarce parts, supplemented by an LED that shows whether the regulator is on or off, and a visual control unit for the installed power. Output voltage from 130 to 220 volts.
Power regulator for soldering station_scheme
This is what the assembled regulator board looks like:
Soldering iron power regulator board assembly
The modified printed circuit board looks like this:
Power regulator circuit board for soldering station
The M68501 head was used as an indicator; these used to be used in tape recorders. It was decided to modify the head a little; an LED was installed in the upper right corner, it will show whether it is on/off, and will highlight the small-to-small scale.
Soldering station indicator
The matter was left to the body. It was decided to make it from plastic (foamed polystyrene), which is used for making all kinds of advertisements; it is easy to cut, well processed, glued tightly, and the paint lays down evenly. We cut out the blanks, clean the edges, and glue them with “cosmofen” (glue for plastic).
Cosmofen glue for gluing plastic
Appearance of the glued box:
External view of the soldering station box
We paint, collect the “offal”, we get something like this:
Appearance of the finished soldering station
Well, in conclusion, if you are going to use soldering irons of different power with this regulator, then in the above diagram it is worth replacing the visual control unit with this one:
Scheme of a modified indicator for a soldering station
With the previous version of the indicator circuit (which does not have a transistor), the current consumption of the soldering iron was measured, and when soldering irons of different power are connected, the readings are different, and this is not good.
Instead of the imported 1N4007 diode assembly, you can install a domestic one. for example KTs405a.
The temperature of the soldering iron tip depends on many factors.
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.
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 circuits and assembly procedures.
This scheme 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.
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:
Then you can gradually increase the power, increasing the voltage to 220 volts.
We make the printed circuit board according to the size of the regulator body. In the proposed version, a housing from a mobile phone charger is used.
The layout is very simple, can be placed in a smaller case. No ventilation is required, the radio components practically do not heat up.
We assemble the device in the housing and take the resistor handle out.
A classic Soviet 40-watt soldering iron easily turns into a soldering station that works more stable than all Chinese analogues.
This option also applies to simple circuits designed for low-power devices. Actually, an adjustable soldering iron. As a rule, it is needed to work with microcircuits or SMD components. And in this case, more power will be unnecessary.
The circuit design allows you to smoothly regulate the voltage from almost zero to the maximum value. We are talking about 220 volts. The power control element is thyristor VS1 (KU208G). Element HL-1 (MH13) gives the control graph a linear shape and acts as an indicator. Set of resistors: R1 - 220k, R2 - 1k, R3 - 300Ohm. Capacitor C1 – 0.1 microns.
If you need to connect a powerful soldering iron to the regulator, the power block diagram is assembled using a KU202N thyristor. With a load of up to 100W, it does not require cooling, so there is no need to complicate the design with a radiator.
The circuit is assembled on an accessible element base; the parts may simply be in your storage rooms.
Principle of operation:
The soldering iron supply voltage is removed from the anode of thyristor VS1. Actually, this is an adjustable parameter that controls the temperature. The thyristor control circuit is implemented using transistors VT1 and VT2. The control module is powered by zener diode VD1 together with limiting resistor R5.
The output voltage of the control unit is regulated using a variable resistor R2, which actually sets the power parameters of the connected soldering iron.
In the closed state, thyristor VS1 does not pass current, and the soldering iron does not heat up. As the control resistor R2 rotates, the power supply produces an increasing control voltage, opening the thyristor.
The installation diagram consists of two parts.
It is more convenient to assemble the control unit on an etched board so that its microcomponents are grouped without a wired connection.
But the power module of the thyristor and its service elements are located separately, evenly distributed throughout the body.
The assembled circuit “on the knee” looks like this:
Before packing into the case, we check the functionality using a multimeter.
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.
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.
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.
I am sure that every radio amateur has encountered the problem of tracks falling off on the getinax and loose tin. The reason for this is an overheated or insufficiently heated soldering iron tip. How to solve this problem? Yes, it’s very simple, or rather a very simple device, the assembly of which even a novice radio amateur will be able to assemble. A schematic diagram of the regulator was once published in a magazine Radio:
About the principle of operation: this circuit makes it possible to regulate the power of a soldering iron or lamp from 50 to 100%. In the lower position of the potentiometer, the thyristor VS1 is closed, and the load is powered through VD2, that is, the voltage is reduced by half. When the potentiometer is rotated, the control circuit begins to open the thyristor and the voltage gradually increases.
You can take the signet. There are two P5 resistors on the board - don’t be alarmed, they just didn’t have the required value. If desired, the signet can be miniaturized; I have it on a larger scale out of principle - in transformerless and power circuits I always wire it on a large scale - it’s safer.
The scheme was used very often during the year and did not have a single failure.
Attention! The soldering iron regulator has a transformerless 220 V power supply. Follow safety rules and test the circuit only through a light bulb!
