Do-it-yourself voltage regulator for a soldering iron. Do-it-yourself soldering iron temperature controller, or a soldering station? Classic thyristor regulator circuit
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 circuit of the regulator, as you can see, it’s probably easier already and nowhere. The diode bridge is assembled on D226 diodes, the 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.
Before the diode bridge for power, you can embed a switch. 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 the VTA 16-600 triac. The difference from the previous version is that there is a neon lamp in the control electrode circuit of the triac. If you stop the choice on this regulator, then the neon will need to be selected with a low breakdown voltage, the smoothness of adjusting the power of the soldering iron will depend on this. A neon bulb can be bitten out of a starter used in LDS lamps. Capacitance C1 - ceramic for U=400V. Resistor R4 in the diagram indicates the load, which we will regulate.
Checking the operation of the regulator was carried out using a conventional table lamp, see the photo below.
If you use this regulator for a soldering iron with a power of not more than 100 W, then the triac does not need to be installed on a radiator.
Option 3.
This scheme is slightly 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 steps of regulation. The thyristor also controls the load. After the diode bridge, there is a conventional parametric stabilizer, from which power is taken for the microcircuit. Diodes for the rectifier bridge, choose such that their power corresponds to the load that you will regulate.
The device diagram is shown in the figure below:
Spam material on the K561IE8 chip:
Diagram of the 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 a soldering iron power control function.
The scheme is quite common, not complicated, repeated by many more than once, no scarce details, supplemented by an LED that shows whether the regulator is on or off, and a visual control unit for installed power. Output voltage from 130 to 220 volts.
This is what the board of the assembled regulator looks like:
The finalized PCB looks like this:
The M68501 head was used as an indicator, these used to be in tape recorders. It was decided to modify the head a little, an LED was installed in the upper right corner, it will show on / off, and illuminate the scale little by little.
The case is left to the body. It was decided to make it from plastic (expanded polystyrene), which is used for the manufacture of all kinds of advertisements, it is easy to cut, well processed, glued tightly, the paint lays evenly. We cut out the blanks, clean the edges, glue with “cosmofen” (glue for plastic).
The temperature-controlled soldering iron allows for low-temperature soldering and tinning to heat parts, flux and solder to set the required soldering temperature, depending on the materials used, and also effectively deal with 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 you to solder microcircuits, radio components, wires, large parts made of different metals and even non-metals with the same soldering iron, ensure a tight fit, eliminate porosity, etc.
Design features and benefits
Russian and foreign manufacturers produce devices for soldering with a power regulator in 3 versions:
- with a built-in body (the tool has a small power);
- in the form of a separately located block with temperature control over a wide range;
- in soldering stations.
In the design of a low-power soldering iron, there may be a rotary dimmer (dimmer), which allows you to change the amount of electric power, either increasing it or decreasing it. Included in the break of the supply cable. In this case, the heating temperature is controlled by the voltage drop, which results in a power drop.
The simplest voltage regulator has only 2 regulation ranges. It can be set to the maximum temperature for which it is designed to perform the soldering process and the minimum temperature that allows you to maintain the heating temperature of the tip.
With the help of 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 power value. Power supply and electronic system controls are in a separate block. A properly selected soldering station will provide the highest quality soldering of any electronic circuit components.
The advantage of a tool equipped with a power regulator:
- during soldering, damage to parts sensitive to the temperature of soldering is excluded and the tracks on the board do not exfoliate;
- performance is not affected by changing the brand of solder;
- flux does not smoke;
- the sting does not wear out;
- the sting does not overheat;
- the consumption of electrical energy is saved;
- extends tool life.
Purchased designs of such devices with temperature control 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 yourself an adjustable soldering iron of both the simplest and more complex designs.
A do-it-yourself power regulator for a soldering iron can be assembled according to primitive schemes and using a microprocessor with information display. It depends on the desire, qualifications and capabilities of the one who wants to make such a device, because the final result of soldering determines the quality of the work of any device where electronic components are present in the circuit. After spending a little time, you can make the available soldering iron adjustable.
The simplest wire resistor power regulator
The simplest do-it-yourself soldering iron temperature controller can be created using only 2 elements: a 25 W wire resistor with a resistance of 1 kOhm (SP5-30) and a rotary knob. The resistor must be enclosed in a housing (necessarily made of a dielectric material), securely fastening it there. It remains to put a knob on the axis of the resistor and you can smoothly adjust the power. Sockets for the plug are made on the case, or the wires of the soldering iron are soldered, and a scale is also set. The simplest device is ready.
Note! The power of such a tool does not exceed 25 watts.
Two-stage power regulator
For the manufacture of 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 turned on, voltage is applied to the tip, when it is opened, it drops by half, which allows you to maintain the temperature of the tip in a gentle mode, i.e. it doesn't overheat or cool down. The device has proven itself in cases where you have to take breaks in work.
The parts are connected in 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 degree of brightness of the glow. In this case, a limiting resistor must be present in the circuit. It turns on in series with the LED.
Dual-mode thyristor circuit
The device, manufactured according to the scheme shown in Fig. below, it is used for soldering irons with a power not exceeding 40 watts. You will need a diode with a current of not more than 1 A for a voltage of 400 V, a KU101G thyristor and a SP-1 resistor. Assembled in a case from charger out of order, or any other plastic box can be used for these purposes. You can use the body of the extension socket single or tee.
For soldering irons of high power (up to 300 W), the regulator is assembled according to the scheme shown in fig. above.
Here 2 parts (power and control) are made separately. Such a device works as follows: when the thyristor is closed (2 transistors control its operation), half the supply voltage is applied 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 that has the right dimensions.
Note! All component leads must be insulated with heat shrink tubing to prevent short circuits.
Power regulator with information display
The figure above shows circuit diagram thermostat on the microcontroller. With its help, the power level is displayed on the indicator and the device is turned off if it has not been working for a long time. Power information is displayed in numbers from 0 to 9, where zero means that the device is not turned on. Numbers from 1 to 9 represent the level of illumination, where 9 indicates full power operation. With 2 buttons, you can decrease or increase the voltage value.
The device has 2 modules (boards): power and digital. The regulator for the soldering iron was assembled on the widespread PIC16F628A microcontroller. Clocking is performed by a built-in oscillator at a frequency of 4 MHz. The power board has elements without transformer 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 controls the duration of the pulses. You can place all the elements of the circuit on one board, but this will make the device bulky. And so 2 of these boards will fit in a small case, for example, a plastic soap dish.
Power regulator using a triac
A triac is two thyristors connected together. This allows current to flow in both directions. With it, the power is adjustable 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 dinistor, a triac and an LED), in the second - 11 parts (5 resistors, a diode bridge, 2 capacitors, 2 diodes and a triac). The diagrams show their values.
Health check
According to whatever scheme the device is made by hand, its performance 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 an LED is involved 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 an LED in series with a resistor in the circuit, the test is carried out using an indicator. If it does not glow, then it is necessary to carry out an adjustment, i.e. pick up 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.
power regulator made with my own hands or purchased in a distribution network, will allow during the soldering process to use the heating temperature of the tip, 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
In order to simplify soldering work and improve their quality, a simple temperature controller for a soldering iron tip may come in handy for a home craftsman or radio amateur. It was this regulator that the author decided to assemble for himself.
For the first time, the scheme of such a device was noticed by the author in the magazine "Young Technician" in the early 80s. According to these schemes, the author collected several copies of such regulators and still uses them.
To assemble the soldering iron tip temperature control device, the author needed the following materials:
1) 1N4007 diode, although any other diode is suitable for which a current of 1 A and a voltage of 400-60 V are acceptable
2) thyristor KU101G
3) 4.7 microfarad electrolytic capacitor 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 a 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 the soldering tip:
In order to better understand the scheme of the device, the author drew how the placement of parts and their interconnection is carried out.
Before starting the assembly of the device, the author isolated and molded the leads of the parts. Tubes about 20 mm long were put on the conclusions 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 to heat shrink. Further, using the above figure and photographs as a visual aid, it is necessary to carefully bend the conductors and not damage the insulation. Then all the parts are attached to the terminals of a variable resistor, while being combined into a circuit that contains four solder points. In the next step, the conductors of each of the components of the device are inserted into the holes on the terminals of the variable resistor and carefully soldered. After that, the author shortened the conclusions of the radioelements.
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 case is an anode, the author decided to isolate it for safety.
To give the design a finished look, the author used the power supply case with a power plug. To do this, a hole was drilled on the upper edge of the case. The hole diameter was 10 mm. The threaded part of the variable resistor was installed in this hole and fixed 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 case, the distance between which was 19 mm, and connectors were installed in the drilled holes with a diameter of 10 mm, which the author also fixed with nuts. Next, the author connected the plug of the case to the assembled circuit and the output connectors, and protected the soldering points with heat shrink.
Then the author selected a handle of insulating material of the desired shape and size, suitable in size, in order to close both the axle and the nut with it.
Then the author assembled the case and securely fixed the regulator knob.
Then I started testing the device. As a load for testing the regulator, the author used an incandescent lamp of 20-40 watts. It is important that when the knob is turned, the brightness of the lamp changes smoothly enough. The author managed to achieve a change in the brightness of the lamp from half to full heat. Thus, when working with soft solders, for example POS-61, using the EPSN 25 soldering iron, 75% of the power is enough for the author. In order to obtain such indicators, the regulator knob should be located approximately in the middle of the stroke.
Devices for adjusting the voltage level supplied to the heating element are often used by radio amateurs to prevent premature destruction of the soldering tip and improve soldering quality. The most common soldering iron powers contain two-positron contact switches and trinistor devices mounted in a cradle. These and other devices provide the ability to select the desired voltage level. Today, home-made and factory installations are used.
If you need to get 40 W from a 100 W soldering iron, you can use the circuit on the triac VT 138-600. The principle of operation is to trim the sinusoid. The cutoff level and heating temperature can be adjusted using the resistor R1. The neon bulb acts as an indicator. It is not necessary to set it. A triac VT 138-600 is installed on the radiator.
Frame
The entire circuit must be placed in a closed dielectric case. The desire to make the device miniature should not affect the safety of its use. Remember that the device is powered by a 220 V voltage source.
Trinistor power regulator for soldering iron
As an example, consider a device designed for loads from a few watts to hundreds. The control range of such a device varies from 50% to 97%. The device uses a trinistor KU103V with a holding current of not more than one milliamp.
Negative voltage half-waves pass freely through the VD1 diode, providing about half of the entire power of the soldering iron. It can be adjusted by the trinistor VS1 during each positive half-cycle. The device is turned on in anti-parallel to the diode VD1. The trinistor is controlled according to the pulse-phase principle. The generator generates pulses fed to the control electrode, consisting of the R5R6C1 circuit that sets the time, and a unijunction transistor.
The position of the handle of the resistor R5 determines the time from the positive half-cycle. The power regulator circuit requires temperature stability and improved noise immunity. To do this, you can shunt the control transition with resistor R1.
Chain R2R3R4VT3
The generator is powered by pulses with voltage up to 7V and a duration of 10 ms, formed by the R2R3R4VT3 circuit. The transition of the transistor VT3 is a stabilizing element. It turns on in reverse. The power dissipated by the R2-R4 resistor circuit will be reduced.
The power regulator circuit includes resistors - MLT and R5 - SP-0.4. Any transistor can be used.
Board and housing for the device
To assemble this device, a board made of foil fiberglass with a diameter of 36 mm and a thickness of 1 mm is suitable. You can use any object for the case, such as plastic boxes or cases made of a material with good insulation. You will need a base for the plug elements. To do this, two nuts M 2.5 can be soldered to the foil so that the pins press the board to the case during assembly.
Disadvantages of SCRs KU202
If the power of the soldering iron is small, regulation is possible only in a narrow region of the half-cycle. In the one where the holding voltage of the trinistor is at least slightly lower than the load current. Temperature stability cannot be achieved when using such a power controller for a soldering iron.
Boost Regulator
Most temperature stabilization devices work only to reduce power. You can adjust the voltage from 50-100% or from 0-100%. The power of the soldering iron may not be enough if the power supply is below 220 V or, for example, if you need to unsolder a large old board.
The operating voltage is smoothed by an electrolytic capacitor, increases by 1.41 times and feeds the soldering iron. The constant power rectified on the capacitor will reach 310V with a 220V supply. Optimum temperature heating can be obtained even at 170 V.
Powerful soldering irons do not need boost regulators.
Necessary details for the circuit
To assemble a convenient power regulator for you, you can use the surface mounting method near the outlet. This requires small components. The power of one resistor must be at least 2 W, and the rest - 0.125 W.
Description of the power boost controller circuit
An input rectifier is made on the electrolytic capacitor C1 with the bridge VD1. Its operating voltage must not be less than 400 V. The output part of the regulator is located on the IRF840. With this device, you can use a soldering iron up to 65 W without a heatsink. They may heat up above the desired temperature even with reduced power.
The key transistor located on the DD1 chip is controlled by a PWM generator, the frequency of which is set by the capacitor C2. mounted on C3, R5 and VD4 devices. It feeds the DD1 chip.
To protect the output transistor from self-induction, a VD5 diode is installed. It can be omitted if the soldering iron power regulator will not be used with other electrical appliances.
Possibilities of replacement of parts in regulators
Chip DD1 can be replaced by K561LA7. The rectifier bridge is made of diodes designed for a minimum current of 2A. The IRF740 device can be used as an output transistor. The circuit does not need an overlay if all the parts are in good order and no errors were made during its assembly.
Other possible options for voltage dissipators
Simple circuits of power regulators for a soldering iron are assembled, working on triacs KU208G. All their cunning is in a capacitor and a neon light bulb, which, by changing its brightness, can serve as an indicator of power. Possible regulation - from 0% to 100%.
In the absence of a triac or a light bulb, a KU202N thyristor can be used. This is a very common device that has many analogues. With its use, you can assemble a circuit operating in the range from 50% to 99% of the power.
From a computer cord, you can use it to make a loop to extinguish possible interference from switching a triac or thyristor.
Dial indicator
A pointer indicator can be integrated into the soldering iron power regulator for greater ease of use. It is quite easy to do this. Unused old audio equipment can help you find these items. Devices are easy to find in local markets in any city. Well, if one such lies at home idle.
For example, consider the possibility of integrating the M68501 indicator with an arrow and digital marks into the power regulator for a soldering iron, which was installed in old Soviet tape recorders. The tuning feature is the selection of the resistor R4. You will probably have to select the R3 device additionally if another indicator is used. It is necessary to maintain an appropriate balance of resistors when lowering the power of the soldering iron. The fact is that the arrow of the indicator can display a decrease in power by 10-20% when the actual consumption of the soldering iron is 50%, that is, half as much.
Conclusion
A power regulator for a soldering iron can be assembled using a variety of instructions and articles with examples of various possible circuits. The quality of the soldering depends largely on good solders, fluxes and the temperature of the heating element. Complex devices for stabilization or elementary integration of diodes can be used when assembling devices necessary to regulate the incoming voltage.
Such devices are widely used to reduce as well as increase the power supplied to the heating element of the soldering iron in the range from 0% to 141%. It is very comfortable. There is a real opportunity to work at voltages below 220 V. High-quality devices equipped with special regulators are available on the modern market. Factory devices work only to reduce power. The step-up regulator will have to be assembled independently.
In amateur radio practice, it is impossible to do without a soldering iron. He is always at the workplace, must be ready. Most simple and common soldering irons have a fixed power, and therefore, the heating temperature of the tip, which is not always justified. Of course, if you turn it on for a short time to quickly solder something, then you can do without a temperature controller.
What is a soldering iron tip temperature controller for?
The most common soldering iron produced by the industry has a power of 40 watts. This power is quite enough for soldering large, heat-intensive parts, where heating to the melting temperature of the solder is required.
But using a soldering iron of such power, for example, when installing radio components, is extremely inconvenient. Tin constantly rolls off the overheated tip, the soldering point is fragile. In addition, the sting very quickly becomes covered with scale and it has to be cleaned off, and so-called craters form on the working surface of the copper sting, which can be removed with a file. The length of such a sting will decrease very quickly.
Using tip temperature controller the soldering iron is always ready, its temperature will be optimal for a specific job, you will never overheat the radio components. If you need to leave for a short time, then it is enough to reduce the voltage on the soldering iron, and not turn it off from the network, as before. Upon returning to the workplace, it is enough to add voltage with the regulator, and the warm soldering iron will quickly reach the desired temperature.
Temperature controller circuit for a soldering iron
Below is simple circuit power controller:
I used this circuit for my regulator 20 years ago, I still use this soldering iron. Of course, some details, such as transistors, a neon light bulb, can be replaced with modern ones.
Device details:
- transistors; KT 315G, MP 25 can be replaced by KT 361B
- Thyristor; KU 202N
- zener diode; D 814B or with the letter V
- Diode;KD 202Zh
- Fixed resistors: MLT-3k, 2k-2 pcs, 30k, 100 ohm, 470k
- Variable resistor; 100k
- Capacitor; 0.1uF
As you can see device diagram very simple. Even a beginner can repeat it.
We make a simple do-it-yourself soldering iron temperature controller
The presented device is built on the so-called half-wave power controller. That is, with a fully open thyristor VS 1, which is controlled by transistors VT 1 and VT 2, one half-wave of the mains voltage passes through the diode VD 1, and the other half-wave through the thyristor. If you turn the slider of the variable resistor R 2 in the opposite direction, then the thyristor VS 1 will close, and there will be one half-wave on the load that will pass through the diode VD 1:
Therefore, with this regulator it is impossible to reduce the voltage less than 110 volts. As practice shows, this is not necessary, since at a minimum voltage the tip temperature is so low that the tin barely melts.
The ratings of the parts presented in the diagram are selected for collaboration with high-power soldering irons. If you do not need it, then the power elements, thyristor and diode can be replaced with less powerful ones. If you do not have a two-watt resistor R 5 with a nominal value of 30 kilo ohms, then it can be made up of two 15 kilo ohm resistors connected in series, like mine:
This device does not require any configuration. Assembled correctly and from serviceable parts, it starts working immediately.
Attention! Be careful. This temperature controller does not have galvanic isolation from the network. The secondary circuits have a high potential.
It remains to choose the appropriate size of the case. Place the socket for the soldering iron:
It is not necessary to bring the fuse out, for example, I have it soldered into the break in the power cord. But the variable resistor must be installed in a convenient place and, of course, the scale must be graduated, for example, in volts:
The resulting regulator is very reliable, which is time-tested, and it will serve you for many years, and the soldering iron will thank you.