Soldering iron from the transformer. How to make a soldering iron with your own hands at home
- Pulse Soldering Iron Device
- Production of a soldering iron having a pulsed principle of action
- Varieties of household soldering irons
- DIY mini soldering iron
- Pulse Soldering Iron Assembly
- Sample soldering iron
- The principle of operation of the soldering iron circuitry
- Transformer power circuit
- Materials needed to assemble the soldering iron
- The sequence of calculation of the details of the electrical circuit
- The effect of efficiency
- Set of magnetic core with transformer iron plates
- Calculation of wire for coil winding
- Determination of the number of turns
- Primary coil
- Secondary coil
- Soldering Iron Assembly
- Power winding
- Ways to improve soldering iron performance
- Production of a pulse microcircuit soldering iron
- electronic principle transformer;
- LED indicators
- copper wire for making a tool tip;
- on-off button;
- plastic case;
- dielectric stand.
- a pen;
- power cord with plug.
Making a pulsed soldering iron with your own hands is not difficult for a person versed in electronics. A soldering iron is the main tool of any master engaged in the repair and creation of electronic equipment. A standard soldering iron is equipped with a heating element, which consists of a wire made of nichrome. The heat released during heating is transferred to the copper tip. A soldering iron can be easily made at home. One of the disadvantages of this design is the time required to heat the soldering iron tip. A home-made pulsed soldering iron does not have this drawback. A homemade tool with a pulsed principle of action heats up to the desired temperature very quickly, in fact, within five seconds and even faster.
Pulse soldering iron is used for mounting elements and components of electrical products.
Most often, the tool tip having a pulsed principle of action is made of copper wire with a diameter of 2 mm. A pulse soldering iron is very convenient when soldering small parts with frequent interruptions during operation and in case urgent work is performed.
Pulse Soldering Iron Device
A pulse soldering iron is a device designed for installation work during the assembly of electronic devices circuits. The heating element of such a device is a sting made of copper wire. The working element is heated by passing a low voltage electric current through it. Impulse action tool uses a small amount electric energy . The high efficiency of such a soldering iron is due to the fact that the electric current is passed through the working tip only during the soldering process. The device consists of a network converter electrical voltage in voltage with high frequency. The converter outputs an electric current with a frequency of 18-40 kHz. In addition, the device includes a high-frequency step-down transformer and a microprocessor control circuit. The secondary winding in the step-down transformer at its ends has current collectors designed to fix the stings on them.
The sting is attached to the current collectors with bolts. Modern pulse devices for soldering have in their design power level indicators and effective illumination of the work area. The case of a modern tool is made of heat-resistant plastic.
The advantages of such devices are low power consumption, low tool weight and compactness, which is ensured by the use of modern high-frequency converters in the design. In addition to the indicator, some devices also have a power regulator, which allows working with both small products and parts electronic circuits significant size. The pulse soldering iron should be used carefully when soldering electronic elements that are very sensitive to high-frequency voltage that occurs on the tip of the device.
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Production of a soldering iron having a pulsed principle of action
The structure of the simplest tool of the pulse principle of operation includes the following structural elements:
The device diagram of a pulse soldering iron is much more complicated than the device of a conventional tool having a heating element in its design. In order to make a pulsed soldering iron with your own hands, you will need to prepare an electronic transformer.
For its manufacture, you can use a switching power supply used to start the lamps daylight with a power of 40 watts. A transformer from such a power supply needs some refinement. Its essence lies in the fact that it requires the removal of the secondary winding and the installation of additional winding in the form of one or two turns copper wire with a diameter of 1 mm. The finished transformer with a modified winding is placed in a pre-prepared housing. The most convenient form of the case will be the form in the form of a gun, in place of the trigger in which a button is mounted to turn on the device.
In place of the imaginary gun barrel, a stand made of a dielectric is mounted on which a loop of copper wire is fixed - a sting. It is connected to the secondary winding of the device transformer; when the circuit is closed with the help of the trigger button, the tip is heated. To visualize the operation of the tool, an LED can be soldered into the circuit. During operation, you should not keep the power button in the “on” position for a long time, as this can lead to overheating and rapid failure of the device.
Do-it-yourself soldering iron is a good alternative to expensive store analogues. A properly designed product will cope with all the tasks that you may encounter in everyday life (restoration of flown contacts, soldering of wires when they are extended, etc.).
Figure 1. Scheme of a simple soldering iron device.
In the modern market of power tools, soldering irons are presented in a wide assortment. It can be both domestic and foreign models, which differ not only in cost, but also in design and operating principle. Therefore, before proceeding with the assembly of a homemade soldering iron, it is necessary to consider the classification of this tool and understand the principle of functioning of each type. With this knowledge, you can make a functional product with which it will work not only conveniently, but also safely.
Varieties of household soldering irons
A soldering iron is an electric tool that is designed to connect metal elements with each other using solder. Metal alloys based on copper, tin, lead, etc. are used as solder.
The simplest soldering iron consists of the following elements (Fig. 1):
Figure 2. Diagram of a mini soldering iron with a nichrome heating element.
The rod and sting are made of red copper. This is due to the fact that this material has high thermal conductivity, due to which heat from the heating element (nichrome spiral filament) is freely transmitted by solder, as a result, the metal is brazed.
In addition to a tool with a spiral heating element (EPSN), there are also other types of soldering irons, among which the most popular are:
- Induction. The principle of its operation is based on an inductor element. Around the ferromagnetic core with the help of an inductor, a magnetic field is formed, which leads to heating of the tip.
- Ceramic. In this tool, a ceramic rod acts as a working element, which heats up when brought to it electric current . Ceramic products are characterized by high efficiency, quick heating of the tip, the ability to adjust the output temperature and durability.
- Impulse. Such a soldering iron outwardly resembles a gun, which is turned on by holding down the start button. The main advantage of a pulse tool is the almost instantaneous heating of the tip (within 4-6 s).
- Rechargeable. A battery is used as a power source. The power of such a product is about 16 watts, so they can only solder simple electronic elements.
DIY mini soldering iron
Figure 3. The pulse soldering iron is designed to perform simple work on the assembly of electronic circuits.
To make yourself a miniature soldering iron for working with microcircuits, you need to prepare the following tools and materials:
- 12 V power supply or transformer;
- heat source (gas or electric stove);
- nichrome wire 0.2 mm thick and 30-35 cm long;
- copper wire with a cross section of 1.5 mm and a length of 3.5-4.5 cm;
- metal tube;
- plastic handle;
- electric cord with plug;
- copper foil;
- silicate glue;
A diagram of a mini-soldering iron with a nichrome heating element is shown in Fig. 2. First of all, a sting is made of copper wire. To do this, one end of it with a file is sharpened to a convenient shape (two-sided corner or cone). Treated areas should be tinned.
Then an insulating solution is mixed from silicate glue and talc. Next, the tip of the future soldering iron must be wrapped with copper foil. In this case, the working part of the product (about 1.0-1.5 cm) should be open. A thin layer of the prepared insulating mixture is laid on top of the foil and dried at a temperature of 120-140 ° C.
Figure 4. Electrical diagram of a homemade pulse soldering iron.
The next step is to wind the nichrome wire. The turns should be tight, the length of the straight end should be about 3 cm, and the inversion should be 6 cm. Then the product is once again covered with the prepared solution and dried at the same temperature.
The long end of the wire is laid on a metal tube so that there is a maximum distance between it and the smaller end. After this, the last processing of the insulating solution and its baking is carried out. The heating element with a sting is ready.
At the last stage, a power cord is drawn through the handle to which the protruding ends of the nichrome wire are connected. Bare spots should be insulated with the remaining mixture. To protect your hands from burns, a special casing of heat-insulating material can be put on the heating element. You need to connect such a homemade soldering iron through a step-down transformer or a power source that produces 12 V.
Pulse Soldering Iron Assembly
Do-it-yourself pulse soldering iron is designed to perform simple work on the assembly of electronic circuits. The working element in it, as in the first example, is a copper wire, the heating of which is carried out using a pulsed electric current of a small voltage (Fig. 3).
Before making a pulse type soldering iron, you need to prepare such tools and materials:
- pliers, nippers, file;
- electronic transformer;
- 1.5 mm thick copper wire;
- copper wire with a diameter of 1.0 mm;
- Light-emitting diode;
- on / off button;
- dielectric rack;
- insulating casing.
The electrical circuit of a homemade pulse soldering iron is shown in Fig. 4. The main element of this tool is an electronic transformer, based on which you can take a 40 W switching power supply installed in fluorescent lamps. In this block, the secondary winding of the transformer should be removed, and then, using a 1.0 mm thick copper wire, make 1-2 turns around the core.
After that, the modified transformer is mounted in a pre-prepared case in the form of a gun. The trigger will be the on / off button of the instrument. In place of the barrel, a dielectric stand is installed with a copper sting at the end in the form of a loop. The working element is connected to the ends of the wire wound on the transformer. When you press the start button, the circuit is closed, as a result of which the copper sting heats up. To visualize the work of the soldering iron, it can additionally be equipped with an LED.
There is nothing complicated in making a soldering iron with your own hands, so everyone can cope with the upcoming work. Do not forget that this product is powered by electricity. Therefore, in the process of work, comply with all electrical safety rules, which will protect you from injury, and the tool from premature failure.
The home master has to do different work, to connect the details in every possible way. Among them, the method of soldering wires, metals and plastics remains one of the most affordable.
Despite the large number of industrial models on sale, you are invited to familiarize yourself with the technology for making a convenient electric soldering iron with your own hands, to understand the principle of its design.
According to the proposed article, it is not difficult to make such a soldering iron.
The indisputable advantage of this model is the almost instantaneous conclusion in the working position of the soldering from the cold state and the rapid cooling of the heating element when turned off.
This significantly reduces the fumes and odors that accompany the extended warm-up of the conventional tip used in resistive models.
Sample soldering iron
Here is such a rare exhibit for the fourth decade continues to work successfully in the home workshop with almost no breakdowns. The dielectric handle is convenient for soldering, the power button controls the heating very easily, and an incandescent light illuminates any shaded workplace.
Power of 65 watts is enough to solder transistors, microcircuits, wires and other electronic products.
The only condition for maintaining operability is to timely replace the working tip - the tip, which, under the influence of high temperature, burns out over time.
The tip is bent with round-nose pliers from a copper single-core mounting wire with a cross-section of 1.5 mm square. At the ends, rings are created that are tightened along the rotation of the fastening nuts. To ensure good electrical contact, the contact points of the wire, washers and power bus must be kept clean, cleaned of soot with a knife or a screwdriver when replacing the tip.
The principle of operation of the soldering iron circuitry
The design is based on an ordinary transformer, consisting of:
- primary winding at 220 volts;
- shorted secondary power winding of two turns;
- magnetic circuit.
For the convenience of soldering, you can create an additional secondary winding of 4.5 volts, which feeds an incandescent bulb from a flashlight or a powerful LED. When the space of the magnetic circuit is limited, it is allowed for the backlight circuit to make a low-voltage branch from the primary winding according to the principle of an autotransformer. Save space and wires.
The power secondary winding is made of a thick copper bus, it constantly works in the short circuit mode to a thinner copper tip. Due to the large thermal effect of the short-circuit current, the soldering iron tip quickly warms up to operating temperature.
Heat removal to the environment and to solder melting in the short-term soldering mode provides a heat balance, eliminating overheating of the transformer and tip windings to a critical temperature.
Transformer power circuit
220 volts is supplied through an ordinary electric plug with a cord. Inside the handle of the soldering iron is placed a microswitch, activated through a normally disconnected contact with the control button.
When you press the power button, voltage is supplied to the transformer, and when released, it is removed. In order to provide power tools, it is recommended to install not a single, but a double micric in the gap of each power wire.
In this design, hazardous will always be absent on the transformer when the circuit breaker contacts are open.
Materials needed to assemble the soldering iron
To assemble a homemade soldering iron you will need to disassemble several transformers of the same type, which were previously widely used in old tube televisions, tape recorders, radios and other similar equipment.
Their transformer iron plates will be used to create the magnetic circuit, and the varnished wires of the winding will go to the winding of the primary coil and backlight.
For the manufacture of a secondary power winding, a copper bus bar of rectangular cross section is required. I have it is 3x8 mm. It is possible a little less, but it is not advisable to significantly lower it electrical resistance chains. Thicker tires will occupy all the free space, will not allow to wind the primary winding.
If a rectangular copper busbar cannot be found, then you can try to use a round conductor of the corresponding cross section.
Also required for assembly:
- electrical plug;
- power cord or wire;
- light bulb;
- a handle that can be used from plastic toy guns;
- paper or varnish for insulation;
- piece of tin for the body.
The sequence of calculation of the details of the electrical circuit
Soldering iron power selection
The main indicator of the effectiveness of the design is the amount of heat released on the sting at the moment of passage of electric current through it. Its strength, specially increased by the short circuit mode, just heats the copper of the tip.
The current passing through the tip of my soldering iron slightly exceeds 200 amperes. Specially checked with clamp meters. But the voltage, even in idle mode, is less than tenths of a volt. Therefore, it is not particularly dangerous when soldering.
The product of the current passing through the power winding by the magnitude of the voltage across it is characterized by the secondary or output power of transformer S2. This value is of interest to us. However, to simplify the calculation, we will begin to operate with the primary power S1, which determines the energy consumption.
It differs by a factor beneficial action - efficiency. Its value of 65 watts is taken as the basis for the industrial design shown in the first photo. For my purposes, I chose 80 watts.
The effect of efficiency
The structural relationship between the secondary power of transformers for electronic devices and efficiency is given in the table.
Efficiency Power in watts 0.95 ÷ 0.98 ≥1000 0.93 ÷ 0.95 300 ÷ 1000 0.90 ÷ 0.93 150 ÷ 300 0.80 ÷ 0.90 50 ÷ 150 0.50 ÷ 0.80 15 ÷ 50
Set of magnetic core with transformer iron plates
The magnetic characteristics of the magnetic circuit and the transformer as a whole are determined by:
- volume of iron;
- and its properties.
We can not particularly affect the second parameter, because we use the iron from the old transformer, which fell under the arm. Therefore, we use the simplest averaged technique, without really going into complex coefficients, corrections, graphs.
For a soldering iron, we can choose a magnetic circuit in one of the forms:
The cross-sectional area for each case is shown in the picture. Here are the formulas for calculation.
Choosing the primary power of the soldering iron in watts and knowing the shape of the magnetic circuit, we calculate Qc - the cross-sectional area according to the empirical formula.
Having determined it and measured the size “A” on the iron, you can calculate the depth “B”, which you need to dial a certain number of plates.
Calculation of wire for coil winding
From the primary power, for example, 80 watts and a voltage of 220 volts, it is not difficult to calculate the current that will flow through the primary coil.
Where d is the diameter of the wire in mm, and I is the current in amperes.
Determination of the number of turns
We use an empirical pattern called the number of turns per volt - ω '. It is calculated:
Qc has already been calculated before. Having determined ω ', this value should be multiplied by 220, because we have such a voltage in the primary winding, and not just one volt.
For the backlight circuit, the voltage is 4.5 volts. We multiply the obtained value of ω 'by it.
Both calculated values: diameter and number of turns are averaged. They will have to vary within small limits, given the fact that the space in the window of the magnetic circuit is limited. It is better to underestimate the diameter of the wire - the soldering iron works in short-term mode.
But with the number of turns, you should be careful. They strongly affect the current-voltage characteristics of the soldering iron and the overall pattern of tip heating.
The power coil is made in two turns.
Soldering Iron Assembly
A conventional coil for winding wire can be made from transformer cardboard or even from ordinary boxes. It is only better to choose a dense material.
Inside the frame, all the iron plates should fit, and between their cavities on the outside, lay the turns of wire. All windings are isolated with varnish or paper. Primary and secondary windings are separated by galvanic isolation.
It will need to be bent out of a copper bar. Such work will help to perform a metal template from a piece of metal according to the dimensions of the cavity of the frame for iron. The work is carried out in a bench vise with accurate hammer blows on the workpiece.
The picture shows the bending sequence started at one end of the shred. It is somewhat easier to carry it out simultaneously from the middle of the winding.
When the shank is bent, its coils are isolated between themselves by a strip of paper, and then placed inside a cardboard frame. It remains to wrap the remaining windings, ensuring their isolation, and put on iron plates, creating their tight fit with the smallest possible gaps.
Before a trial start, a transformer must be assembled in order to identify errors that may lead to a short circuit in the primary network. Also make sure that it protects your wiring.
It is important to measure the resistance of the insulation created relative to metal case a soldering iron with a megohmmeter, through which leakage currents can occur if improperly assembled. It is necessary to monitor it periodically, but it is better to install it immediately in the apartment panel.
Ways to improve soldering iron performance
If during the soldering process the soldering iron overheats the tip or is able to bring it to normal temperature, then you can adjust its operation by changing the thickness of the copper wire used for the tip.
A thinner conductor will heat up faster, and a thicker one will last longer.
The optimum copper cross-section for the tip is 2.5 mm square. From this value and begin testing the soldering iron.
Concluding the article, I propose to watch on its topic a useful video on soldering techniques for beginners and not only the owner of CHIP'n'BASS.
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We have long been interested in a mini soldering iron with instant heating. In this issue, the master showed how to make and how such a device works.
There is a step-down network power supply. The secondary winding of the transformer is closed by a sting. She is from over thin wire than the winding itself. At short circuit the sting will heat up. For this device, old 60-watt electronic transformer boards came in handy. Dismantled into parts, developed a compact board. Assembled the block on a new board. It is advisable to check all components, even if they are new. It is convenient to do this using a transistor tester. Pay download. Everything you need for him, you can buy cheaply in this Chinese store.
Power transistors are strengthened from the side of the tracks. You can use keys such as 1303, 13005 or 13007. You can take the latter from a computer power supply. To make the instant soldering iron compact and convenient, I had to abandon the regular core that stood on the board electronic transformer . In search of the right solution, I came across an old laptop power adapter. On the power wire of such adapters has a kind of interference filter in the form of a ferrite barrel. This is a torus, which just needs the overall dimensions for the intended purpose. The master took the primary winding from his own transformer, which stood on the circuit board and wound around this core.
It is undesirable to do a winding on a bare frame. The master did not have at hand a suitable insulating material, work was carried out in a hurry. As a result, about 6 hours were spent on the complete assembly, taking into account the development and etching of the board.
The secondary winding contains only one turn. Winding double wire 3.5 millimeters. Despite the fact that the wire has varnish insulation, it is advisable to use an additional one. Better tube made of fiberglass, in extreme cases, heat shrink.
The transformer was attached to the board using epoxy. An instant soldering iron circuit in front of you.
Everything is standard. The push-pull network generator, the diode bridge is designed for a current of 1 amp. Transistors need a heat sink. Cases must be isolated from the radiator.
The final assembly and assembled unit must be tested. We must not forget about security measures. Be sure to connect the network lamp as shown in the figure.
After making sure everything is working properly, the lamp can be removed.
The housing is preferably made of solid heat-resistant insulating material. Ebonite or fiberglass. Especially high temperatures are not formed inside the case, so you can limit yourself to plastic. Boxes of chewing gum will do. In some places of the body, it is necessary to drill holes. This provides natural cooling circuitry. The holder for a sting is made of mounting terminals convenient size. A tip from an industrial soldering iron. The material is allegedly stainless steel. It is permissible to use copper wire bent similarly. During the initial instantaneous heating of the sting, the device can consume up to 8 watts from the mains despite the fact that the power supply is 50-60 watts. After proper heating, the soldering iron tip will consume a power of about 35-40 watts maximum.
The diameter of the wire for the sting in the case of copper is from 1 to 2 millimeters. The soldering iron is activated by pressing a button. The button should be designed for mains voltage and a minimum current of 1 ampere. It turned out quite convenient, lightweight, compact. It is ready to work in 8-10 seconds after switching on. You can make a narrow elongated board, then the soldering iron will become thinner and more comfortable to hold in your hand and take advantage of instant heating.
Scheme and Description
Inside a simple home-made design is a low-power transformer for 50 W from some kind of adapter. Its secondary winding of 12 volts consists of 8-10 turns, you need to carefully unwind it, for which it is necessary to disassemble the transformer.
Instead of this winding, I wound a power winding from one turn with a cross section of 6 mm, using a screen from the antenna cable. After winding the winding we betray stability. To do this, insert pieces of cardboard from the sides of the transformer core. After that, carefully assemble the transformer back.
Then we tin the ends of the windings and connect the power to the circuit. We close the ends of the winding stranded wire , which should either warm up in a few seconds, or melt. The voltage at the construction output is about two volts, but the current can reach 25 amperes.
In principle, the soldering iron is ready, but you need to think over the option with a sting. It is easiest to make it with your own hands from a thick copper wire see photo.
It remains to figure out how you can screw the sting to the tire with bolts or spot welding, or maybe you’ll come up with something better.
The resulting design was placed in a case from under a children's electronic pistol. Such an amateur radio tool warms up in a matter of seconds, and during operation, the circuit does not overheat. Heat can be transferred from the tip to the bus, so it is not advisable to keep such a soldering iron on for a long time.