Alteration of an electronic transformer for an electric screwdriver.

Alteration of an electronic transformer for an electric screwdriver

Electronic transformer. Network pulse power supply, which is designed to power halogen lamps 12 volts. Read more about this device in the article “Electronic transformer (familiarization)”. The device has a fairly simple circuit. A simple two.stroke auto generator, which is made according to a half.power scheme, the operating frequency is about 30 kHz, but this indicator is highly dependent on the output load. The circuit of such a power supply is not very stable, has no protection against KZ at the transformer output, perhaps precisely because of this, the scheme has not yet found widespread use in radio amateur circles. Although recently on different forums there has been a promotion of this topic. People offer various options for finalizing such transformers. Today I will try to combine all these improvements in one article and offer options not only to refinition, but also torturing this.

We will not go into the basis of the work of the scheme, but immediately get down to the case. We will try to finalize and increase the power of Chinese ET Taschibra by 105 watts.

To begin with, I want to explain why I decided to take up the speculation and alteration of such transformers. The fact is that recently a neighbor asked him to make a charger for a car battery to order him, which would be compact and light. I did not want to collect, but later I came across in which the alteration of the electronic transformer was considered. This prompted the idea. Why not try?

Thus, several AT from 50 to 150 watts were purchased, but the experiments with the alteration did not always end successfully, of all, only 105 watts survived from all. The disadvantage of such a block is that its transformer is not ring, and therefore it is inconvenient to rewind or harness the turns. But there was no other choice and had to remake this particular block.

As we know, these blocks are not included without load, this is not always a virtue. I plan to get a reliable device that can be freely used for any purpose, not afraid that the power supply can burn out or fail with a short circuit.

The essence of the idea is to add protection against KZ, also eliminate the above deficiency (activation of the scheme without output load or with low.power load).

Looking at the block itself, we can see the simplest IBP scheme, I would say that the scheme has not been fully worked out by the manufacturer. As we know, if you close the secondary winding of the transformer, then less than in a second the scheme will fail. The current in the circuit increases sharply, the keys in a moment fail, sometimes basic limiters. Thus, the repair of the scheme will cost more than the cost (the price of such an is about 2.5).

The feedback transformer consists of three separate windings. Two of these windings feed the basic circuits of keys.

First, remove the communication winding on the OS transformer and put the jumper. This winding is turned on sequentially with the primary winding of the pulse transformer. Then, on the power transformer, we wind only 2 turns and one turn on the ring (OS transformer). For winding, you can use a wire with a diameter of 0.4-0.8 mm.

Next, you need to choose a resistor for the OS, in my case it is 6.2 Ohms, but the resistor can be selected with a resistance of 3-12 Ohms, the higher the resistance of this resistor, the less the protection current from the short circuit. The resistor in my case used a wire, which I do not advise doing. The power of this resistor select 3-5 watts (you can use from 1 to 10 watts).

During the KZ on the output winding of the pulsed transformer, the current in the secondary winding falls (in standard schemes of the ET with a short circuit, the current increases, disabled the keys). This leads to a decrease in current on the winding of the OS. Thus, the generation stops, the keys themselves are locked.

The only drawback of such a solution is that with a long.term short.circuit at the output, the scheme fails, since the keys are warming up and strongly. Do not expose the output winding of KZ with a duration of more than 5-8 seconds.

The scheme will now start without a load, in a word we have received a full.fledged UPS with protection against KZ.

Now we will try, to some extent smooth out the network voltage from the rectifier. To do this, we will use throttle and smoothing capacitor. In my case, a finished throttle with two independent windings was used. This throttle was removed from the IBP DVD of the player, although you can use home.made chokes.

After the bridge, you should connect an electrolyte with a capacity of 200 MKF with a voltage of at least 400 volts. The capacitance of the capacitor is selected based on the power of the power supply unit 1 MKF per 1 watt power. But as you remember, our BP is designed for 105 watts, why is the capacitor used for 200MKF? You will understand this very soon.

Now about the main thing. the destiny of the electronic transformer and whether this is realistic? In fact, there is only one reliable way to confess without special alterations.

It is convenient to use ET with a ring transformer for speculation, since it will be necessary to rewind the secondary winding, for this reason we will replace our transformer.

The network winding is stretched throughout the ring and contains 90 turns of wire 0.5-0.65mm. The winding is wound on two folded ferrite rings, which were removed from ET with a capacity of 150 watts. The secondary winding is wound on the basis of the needs, in our case it is designed for 12 volts.

Impulse power supply for electrical screwdriver 18 V: Scheme

There is a way out, and he is not alone. You can purchase a new battery. But the price of such a device can exceed the cost of the entire tool as a whole, bought several years ago. Therefore, the most acceptable solution will be the of an electric screwdriver for the network voltage.

Options for connecting an electric screwdriver to the network 220 in

One of the solutions will be the creation of a power supply with your own hands. There are many options for creating a home.made power supply:

  • universal option;
  • with a two.pole resistor;
  • with a three.pole resistor;
  • with an amplifier;
  • on the zener diode and without;
  • On one filter.
alteration, electronic, transformer, electric

However, they have established themselves as the most reliable impulse modifications.

alteration, electronic, transformer, electric

Component elements of the circuit of the pulse power supply unit

Make a pulse power supply for a manual instrument 18 V with your own hands is completely easy. This will need:

  • Output capacitor 5 pf.
  • Resistor.
  • Integral transducer of negative orientation.
  • Two or three bookmarks comparator.
  • Low.power rectifier.
  • Channel filters with radiation adapters.
  • The scheme of the pulse power supply circuit.

Connection of the battery electrical screwdriver to the 220 V network: Network adapter

Drive the electric drive of an electrical screwdriver from a network with a voltage of 220 V can a network adapter. It can be purchased in the finished form. the price allows. You can do it yourself. The purchased adapter must be inserted into the battery of the electric screwdriver battery, having previously removed the batteries. The only drawback is the small length of the cord.

DIY network adapter for electric screwdriver: Materials

If there is a need to make a network adapter with your own hands, then charging for a laptop is ideal for this.

alteration, electronic, transformer, electric

The process of alteration of the battery electrical screwdriver in the network is simple and does not take much time. To do this, you need to have:

  • Charger from the laptop.
  • Electric screwdriver with a used battery.
  • Electric wire.
  • Island.
  • Soldering iron and solder.
  • Acid.


The processing process includes the following actions:

  • First you need to measure the output voltage on the device. It should be 19 in.
  • After that you need to take the battery and disassemble. If it is twisted with screws, then simply develop them, if it is glued, then you must first stand with a rubber hammer. Clean the body from the dirt and prepare for further work, drilling a hole for the power cable in it.
  • Now you need to cut off the connector and clean the wires from insulation.
  • The battery should not be thrown away immediately. For some time it can serve as a counterweight. The center of gravity of the electric screwdriver is shifted and located in the area of ​​the handle. When removing galvanic elements, its place will change, and working with the tool will be inconvenient.
  • To the wires coming from the battery terminals, you need to attach an elongated cable from charging a laptop. Previously, it must be passed through the prepared hole in the case. The cable can be soldered or twisted, insulating with the tape.
  • When everything is ready, you need to put everything in the case and check the polarity. After that, test the electric screwdriver.

Possible power sources

So that any electric screwdriver can function from the network, it needs to ensure the transformation of the voltage: the tool requires only 12, 16 or 18 volts. All power sources are divided into 2 large groups: they can be impulse or transformer.

Impulse systems

In these power supplies, the input voltage is first straightened, then it is converted into high.frequency pulses. They are served through a transformer or through ordinary resistors. The second method makes it possible to get a small.sized design, since there is no massive power transformer in the scheme.

This power supply for electric screwdriver usually has a rather high efficiency, reaching 98%. The plus of the solution is a short circuit protection, safety that the lock without load guarantees. The disadvantages have pulse blocks. This is lower power, when comparing this value with the transformer option. If the lower load limit is minimal, then such a power supply cannot work. Another drawback is a more complex repair in the event of a pulsed BP out of order.

Transformer block

This is a classic device. The linear power source includes a lowering transformer and rectifier, which turns alternating current into constant. The last element is of two types. a single.sulfur, consisting of one diode, or a two.sulfur, in its composition, a diode bridge assembled from 4 electronic devices.

The transformer block diagram may include a capacitor, stabilizer, high.frequency filter and short circuit protection. Advantages of the device: simplicity, reliability, maintainability, lack of interference, as well as very expensive elements. Cons. large dimensions and the same weight, low efficiency. Since part of the voltage takes the stabilizer, the output value must be higher than what is required for the operation of an electric screwdriver. For example, for a 12 V tooling tool, a power supply from 12 to 14 volts has an output voltage.

What is required for modernization?

The necessary set of materials and tools may include:

  • insulating tape;
  • cable (multi.core) and wires (for jumpers);
  • BP box (old battery, purchased finished device or home.made design);
  • Kusachki;
  • multimeter;
  • screwdrivers;
  • Passatigi;
  • soldering iron, solder, acid;
  • Construction knife.

Before you start making a power supply for an electric screwdriver, you need to take into account the dimensions of the device: you need such a case that the assembled design in it is placed.

How to make power supply units from energy.saving light bulbs?

Modern power tools are popular in that during operation they allow us not to be attached to the power grid, which expands the possibilities of their operation, even in the field. The presence of a battery significantly limits the duration of active work, so screwdrivers and drills require constant access to a power source. Unfortunately, in modern tools (often Chinese production), the supply battery has slight reliability and often quickly fails, so the craftsmen have to do with improvised materials in order not only to collect the pulse power supply, but also to save money on this. An example of such a hand-mail is an impulse power supply (UPS) for a 18 V battery of a non-working energy-saving lamp, which can be beneficial even after its “death”.

Structure and principle of operation of an energy.saving lamp

To understand what the energy.saving lamp can be useful, consider its structure. The design of the lamp consists of the following components:

  • Sealed glass tube (flask), inside covered with fluorephoreophone composition. The flask is filled with inert gas (argon) and mercury pairs.
  • Plastic case made of non.combustible material.
  • A small electronic board (electronic ballast) with a starting device (PRO), which is responsible for starting and excludes the flickering of the device. PRO of modern devices is equipped with a filter that protects the lamp from network interference.
  • A fuse that protects the components of the board from the voltage jumps, which can cause the fire.
  • Corps. in it “packed” PRO, fuse and connecting wires. On the housing placed a marking that contains information about voltage, power and color temperature.
  • Basement that provides contact with a power lamp (the most common basins. E14, E27, GU10, G5.3).

Two spirals (electrode) are connected to the lamp flash, which are repented under the influence of current and emit electron from their surface. As a result of the interaction of electrons with mercury vapors, a smoldering charge occurs in the flask, “giving birth” to UV radiation. Acting on the phosphor, ultraviolet “forces” the lamp glow. The color temperature of the “economy” is determined by the chemical composition of the phosphor.

Types of breakdowns of energy.saving lamps

An energy.saving lamp may fail in two cases:

  • The lamp flap broke;
  • Electronic ballast (EB) (high.frequency voltage converter), which is responsible for converting alternating current into constant, gradual heating of the electrodes and prevents the device’s flicker during inclusion.

When the flask is destroyed, the lamp can simply be thrown away, and when breaking electronic ballast, it is repaired or used for its purposes, for example, use the UPS, adding a dividing transformer and rectifier to the circuit.

The equipment of the electronic ballast of the energy.saving lamp most EB lamps are high.frequency voltage converters collected on semiconductor triodes (transistors). expensive devices are equipped with a complex EB scheme, respectively, cheaper. simplified. Electronic ballast “Puttered” by the following electrical elements:

  • a bipolar transistor operating at voltages up to 700 V and currents up to 4A;
  • protective diodes (mainly elements of the type D4126L or similar to them);
  • impulse transformer;
  • throttle;
  • bicentified dinistor, similar to the dual KN102;
  • condenser 10/50V
  • Some EB circuits are equipped with field transistors.

The figure below shows the composition of the electronic ballast of the lamp with a functional description of each element.

Some EB schemes of energy.saving lamps allow you to almost completely replace the scheme of a home.made impulse source, complementing it with several elements and making small changes.

Separate converter circuits work on electrolytic capacitors or contain a specialized chip. Such EB schemes are better not to use, because they are often the sources of failures of many electronic devices.

What is common between electrical circuits “Enopomes” and UPS?

Below is one of the common electrical circuits of the lamp, supplemented by a jumper A-A ’, replacing the absent parts and a lamp, a pulsed transformer and a straightforward. Elements of the scheme highlighted in red, you can remove.

As a result of some changes and the necessary additions, as can be seen from the scheme below, you can collect the pulse power supply, where the added elements are highlighted in red.

What power parameters can be obtained from an energy.saving lamp?

The “second” life of “economics” is often used by modern radio amateurs. Indeed, their hand-made is often required by a power transformer, with the presence of which certain difficulties arise, starting it with a purchase and ending with a large amount of wire for winding and the overall dimensions of the final product. Therefore, people’s craftsmen got used to replacing the transformer with a pulse power supply unit. over, if for these purposes, use electronic ballast of a faulty lighting device, this will significantly save funds, especially for a transformer with a capacity of more than 100 W.

The low.power impulse power supply can be built by the secondary winding of the frame of the existing inductance coil. To get a power supply unit, an additional transformer will be required. The pulse power supply for 100 watts can be made on the basis of an EB of lamps with a capacity of 20-30 W, the circuit of which will have to be changed slightly, complementing it with the rectifying diode bridge VD1-VD4 and changing the cross-section of the winding of the throttle L0.

BP for electric screwdriver from an electronic transformer

Taschibra power transformer power transformer

Some novice radio amateurs, and not only, are faced with disadvantages at the stage of production of massive power sources. At the moment, solid volumes of electrical transformers used to power halogen lamps have appeared. The electronic transformer is essentially a semi.moisture auto.generator pulse voltage converter. Impulse converters have the highest efficiency, small sizes and weight. These products cost quite cheaply, approximately 1 for one watt. After refinement, they can be used to feed radio amateur structures. There are many articles on this topic on the network. I wish to share my experience with remaking an electronic transformer

Let’s see the principle diagram of the electrical converter. The network voltage through the fuse enters the diode bridge D1-D4. The straightened voltage nourishes the semi.moisture converter on transistors Q1 and Q2. In the diagonal of the bridge formed by these transistors and capacitors C1, C2, the winding I pulse transformer T2 is included. The start of the converter is provided by a chain consisting of resistors R1, R2, capacitor C3, diode D5 and Diac D6. Feedback transformer T1 has three windings. Toki.consuming customers winding, which is turned on alternately with the primary winding of the power transformer, and two windings of 3 turns that feed the basic circuits of transistors. The output voltage of the electric transformer is essentially rectangular pulses with a frequency of 30 kHz, modulated by a frequency of 100 Hz.

Read how to set the ignition on Stihl 180

transformer as a power source, it needs to be finalized.

We connect the capacitor at the output of the rectifier bridge to smooth out the pulsations of the rectified voltage. The container is selected at the rate of 1 MKF per 1W. The operating voltage of the capacitor will be more than 400V. When the rectifier bridge with the capacitor is included in the network, a throw of current appears, therefore it is necessary to include the NTC thermoresistor or a 4.7 Ohm 5W resistor in the network wires. This will limit the starting current.

Screwdriver power supply on an electronic transformer

NEElectronic transformer. Testing the power block of the elastic transform.

Power supply for electric screwdriver from an electronic transformer part1

We run around for registration and start making money.

If you need another output voltage, rewall the secondary winding of the power transformer. Wire dialect (wire burn) is selected pushing off from the load current.

Electric transformers have an OS in current, because the output voltage will vary. If the load is not connected, the transformer will not start. If you set this goal did not happen, it is necessary to change the communication circuit with customers in the current to the OS by voltage. We delete the winding with customers on the current and put it on the board. We put a jumper. Then we skip a flexible multi.wire wire through a power transformer and do 2.4 turns, then let the wire through the transformer of communication with customers and make one round. The ends missed through the power transformer and the wire feedback transformer are connected through two parallel.connected resistor 6.8 Ohms 5 W. This current.limiting resistor establishes the transformation frequency (approximately 30 kHz). With an increase in load current, the frequency becomes than easy. If the converter does not start, you need to change the direction of winding.

Read power supply for electric screwdriver on IR2153

In Taschibra transformers, transistors are pressed to the case through cardboard, which is dangerous during operation. Among other things, the paper is very poorly carried out heat. Therefore, it is better to install transistors through the heat conductive gasket. To straighten the alternating voltage with a frequency of 30 kHz at the output of the electric transformer, we install a diode bridge. The best results were shown among the tested diodes, KD213B (200V; 10A; 100kHz; 0.17mks). With huge load currents, they heat up, because they need to be installed on the radiator through thermal stripes. Electric transformers do not work well with capacitive load in another way, do not start in general. For normal work, you need a smooth start of the device. The thrust start is promoted by the throttle L1. Together with the 100MKF capacitor, he additionally makes the function of filtering rectified voltage. The L1 50Mcg throttle is wound on the T106-26 of the Micrometals offices and contains 24 turns with a wire of 1.2mm. Such cores (yellow, with one snow.white line) are used in computer power supply units. External diameter 27mm, internal 14mm, and height 12mm. When, in the killed power supplies you will find other details, the thermoresistor.

Read how to check the battery of an electric screwdriver

If you have an electric screwdriver in other words of another tool that has a battery has developed your own resource, then in the case of this battery there is an option to place a power supply from an electric transformer. For reason, you get a tool working from the network. For measured operation at the output of the power supply, it is better to put a resistor of about 500 Ohms 2W.

Further refinement

As a load and at the same time indication on the output conclusions of the transformer attacked several light bulbs on 12 and 26V low power, respectively, 5-12-volt. Here is the schematic image of the transformer on the part of the conclusions and the scheme. At least I have such (“basement” can be determined by the board from which the transformer is dropped):

In. “network” winding, GND. “pigtail”, which goes out from above the transformer is the average point of secondary windings.

volt windings are wound up with a double wire and patronized on the corresponding pairs of the transformer conclusions.I included in the network (at first sequentially with an incandescent lamp 220 × 60). All indicator bulbs lit up like a Christmas tree garland! The 220 × 60 lamp did not even flare up. there is an electrolyte of small capacity. 6.8 μF x 400 V.

After a couple of minutes, he turned off, felt the elements, observing the main rule of the electrician. hold one hand in his !. All elements were cold! Then I increased the load. I soldered a 10 W automobile lamp and turned on the network directly. it works! Having turned off, I felt the elements. cold. He left for half an hour. Transistors and trance. slightly warm. Attached small aluminum radiators to transistors. they do not bask. The radiator attached a strip of electrole to one radiator. the radiator was in dangerous proximity to the network voltage switch.

I tried different ships (I have three of them). the brightness of the lamps changes slightly. This is explainable-once experimented with them according to the methodology from the Datagor article “The old computer BP-a new life in audio!”And I found that the sections of the primary winding have a different number of turns, and the difference is significant. up to 40%! Sushing Chinese distraction.

For straightening, we take two ER302 diodes from the same ath. Save the anodes to 12. the voltage conclusions of the transformer.

Note. For 12-14 volt batteries we connect to 5-volt conclusions. Further to the cathodes-the output voltage throttle voltage, on which only a 12-volt winding is left. Without a throttle, an electric screwdriver works unstable. And complet this chain in parallel on the electrolyte of 100 μF x 63 in minus to the “pigtail” of the transformer and ceramics 0.1 μF.

I thought to make a scarf, but then I decided to make a canopy. it’s easier and more clearly. Trans and throttle are attached to the bottom of the battery container from which the batteries are removed, with nylon ties plus thermoclei. during operation there may be strokes and falls. And vibration. We screw the energy.saucer with a screw M3 with a nut and a spring puck to the bottom of the container. Radiators are fastened together with a wooden spacer with small self.tapping screws. We wrap the ends of the spacers for strengthening with a harsh thread (the thread. what a harsh horror. it is scary to approach!) and impregnate PVA.

We connect an electric screwdriver, observing polarity. We turn on. it works at both speeds! We try to stop the hand. the speed is slightly reduced, but it is impossible to stop! Collect, install the switch. The yellow LED is installed for. Yes, I was just with me! Yes, and the indication is noticeable, especially when the voltage is drawn under load (by the way, you can organize local lighting of the working area).

Voltage on capacitors without a load of about 22.5 V. the same as UX.X. 15 batteries of 15 accumulators. We solder the ballast resistor 3 kom to the output of the LED and enclose in a thermal shrink. We connect the LED parallel to the capacitors.

P.S. I have a network electric screwdriver. Everything is fine, but he does not have a shaft electrical device! And it has!

I think such an UPS can be screwed to other devices. If you strengthen the conductors on the board and other elements (not forgetting to replace the thermistor with ATH. Sky), watts 200, at least, you can swing from it.

Update from 28.12.2019

The power supply is very powerful, completely copes with a long drill. In implementation without OS by voltage, the unit can be connected to the network at least a whole day. There is no heating.

However, during operation, a significant drawback was revealed at the facility: when jaming the engine shaft, power keys can burn out. I always flew out a “minus” transistor (lower in the scheme), and the second remained whole.

Since the jamming of the shaft is equivalent to a short circuit at the output of BP, you need to take measures that eliminate this phenomenon. Let’s look at the work of the battery tool. Due to the “soft” voltage characteristic (VAH) of the battery, with too large loads and jamming too much, the voltage is planted, as a result of which the current is reduced.

I consider it to be irrelevant in the “hot” part of the block, because with large loads, protection will often work and convenience in work will be lost. Still, measures to “mitigate” the VAH seem to me more acceptable.

It will be very interesting to know your experience if you collect the scheme and try to make the shaft “soft” jacket. Contacts in the basement of the site.

Using LED driver

For a 12-volt tool, such a driver is the easiest option, although not the cheapest. The only condition is that the driver’s power should be 10-15 % more than the power of the tool. Otherwise, the power supply will be defended by starting the tool, and if it launches it, it will not allow you to develop sufficient power to tighten the screw.

alteration, electronic, transformer, electric

If, for example, a 12-volt screwdriver consumes a current of 10 A, then the power of the power supply should be at least 130 W. For a 30-ampere tool, you already need a 400-watt power supply unit. Finding such a device, of course, is not a problem, but its cost may exceed the cost of the screwdriver itself.

How to redo the screwdriver for such a power supply? If the standard battery fails, then we simply disassemble it, take out the batteries, and we solder the wires connected to the driver’s output clamps to the instrument to the instrument, be sure to observe the polarity. We connect the driver to the network through the input terminals. and the alteration is over. We insert the battery into a screwdriver. and we use.

If the battery is working, then, of course, it is not necessary to destroy it. Just disassemble the screwdriver and we plow the power block to the supply terminals of the instrument itself. The block, of course, is removed out, we equip the food wire with the response part of the connector. Connected the connector. we work from the network. They turned off the PSU, installed the battery. and we have an autonomous tool.

Important! 10 A is a decent current, so the cross.section of the wires should be large enough, and their length is as low as possible (within reasonable limits). Otherwise, there will be a large voltage drop on the supply wires, and the screwdriver will not develop the desired power.

Alteration of the electronic transformer

A good and rather compact power supply can be made from the so.called electronic transformer (ET) designed to power low.voltage halogen lamps.

But in order to use the transformer together with the screwdriver, it (block) must be finalized. Take a look at the classical scheme of the simplest ET.

This is the simplest impulse reducing power source assembled according to a two.stroke scheme. The output voltage is removed from the secondary winding of the output transformer. The scheme given in the figure, of course, is not the only. There are easier devices, it is more difficult. There is a stabilization of the output voltage, a smooth starting system and protection against short circuit. But what interests us is an unchanged part of any electronic transformer. So, what’s the difficulty?

The problem is that the output voltage of such BP variables with a frequency is dozens of Killerz, and even modulated by a frequency of 50 Hz. It is suitable for eating incandescent lamps, but not suitable for screwdriver. So, it needs to be straightened and smooth out. To do this, use the VD1 diode and two smoothing capacitors. C1 and C2, connecting them according to the scheme below.

The H1 lamp serves as a load when the screwdriver is disconnected. It is necessary to start the converter. without load it simply will not start. The high.voltage electrolytic capacitor can be taken from the PSU for a computer or any other device, say, from a TV with a pulsed power supply. It is located in the electronic transformer case. The diode and the capacitor are placed in the tool case, and the lamp is installed so that it also illuminates the workplace. it killed, as they say, two hares at once. Such a lamp will be much more convenient than standard backlight, which turns on only with the tool. You are blindly aiming in the dark, then you start a screwdriver and look where you get.

Diode KD2960 is a fast.acting rectifier diode designed for current 20 A and withstanding reverse voltage 1200 V. Its foreign analogue. 20ets12. It will not be possible to replace this diode with ordinary rectifier. it has too low performance, and at a frequency of dozens of Killerz he will warm up more than straightening.

But there is a replacement. Schottki diode is quite suitable for 15–20 A and reverse voltage at least 25 V. You can find such diodes in PC power supplies. There they serve for the same purposes. The diode, of course, needs to be put on a heat voltage.

The light bulb is miniature. It can be found in Soviet New Year garlands or use two by 6.3 V, included in series. Collect the rectifier, place it in the tool case, remove it through the made hole of the wire, we plow one part of the connector. The second is solder to the wires from the transformer. and the finalization is completed. Since the voltage at the output of the electronic transformer is alternating, the polarity of connecting the wires from floor to rectifier can not be observed.

As indicated above, there are transformers that provide a smooth launch of halogen lamps. Whether they are suitable for us? Quite. As soon as we connect this to the network, it will start and will go out for a working mode within 1-3 seconds. this will be clearly visible in terms of smooth flame of the H1 lamp. After that, the tool can be used without problems.

DIY power supply unit for electric screwdriver

The standard charger uses a chip. On it, depending on the voltage, there are a different number of transistors, for example, 4 transistors are placed in the charger for 12 volts. To reduce the negative effects of the clock frequency, capacitors are installed in the blocks. They are impulse or transitional type. To minimize the consequences from overloads of the electric network, thyristors are used in charging devices.

Standard charging scheme of electrical screwdriver

This is important: in various models, not only a different number of transistors is established. they differ significantly in their capacity.

A power supply unit for an electric screwdriver from an energy.saving lamp in order to make an UPS from an energy.saving lamp, you need to change the electronic throttle in each lamp, putting the jumper, and then connect to the pulse transformer and rectifier. For power sources of small power (from 3.7 in up to 20 watts), you can do without a transformer. To do this, you just need to add a few turns of the semiconductor to the magnetic circle of the throttle lamp located in the ballast if there is a place for this. The winding can be made directly over the factory. To do this, it is better to use a wire with ftoroplast insulation.

Power supply for electric screwdriver from charger

One of the cheapest ways to make a power supply is to use a regular charger for a smartphone. There are two or more of them in each house, and if you have no superfluous, you can purchase for 50–100.

This is how the insides of charging from the smartphone look like

Alteration of charging is carried out in the following sequence:

Using an enameled conductor of small diameter, you need to add one round of the winding. After that, turn on the charging and connect to the battery of the electric screwdriver. By means of oscilloscope, we measure the amplitude of the pulses and determine the voltage created by one turn of the additional winding. Out the USB connector, remove the test turn and house the right number of turns until the required voltage is obtained. The new winding is soldered to the factory sequentially. We change the standard capacitor and zener diode to new ones corresponding to the required voltage.

DIY Electric screwdriver Impulse Block

For the pulse block, a suitable microcircuit is selected, and the assembly is carried out in the following sequence:

Diode bridges and thermistor are placed at the entrance. Two capacitors are installed. Drivers are used to synchronize the operation of field transistors. When installing transistors, flanges do not shake. Using insulating washers and gaskets, they are attached to the radiator. Diodes are installed at the output.

Electric screwdriver power supply from an electronic transformer

To adapt the transformer to the charger of your tool, it needs to be finalized. To do this, you need to connect the capacitor at the output of the rectifier bridge. The capacity is determined as follows. 1 μF per 1 W. The voltage of the capacitor should be at least 400 V. The thermoresistor needs to be installed in the gap of one network cable to limit the starting current. The diode bridge is installed to straighten the voltage with a frequency of 30 kHz. For the normal functioning of the device, it is necessary to ensure a smooth start. The throttle L1 copes with this perfectly.

DIY rectifier for electric screwdriver

The rectifier is necessary for converting alternating current into constant. It functions due to semiconductor diodes that play the role of converters. To analyze the operation of the device, use the oscilloscope. The main thing in the manufacture of the rectifier is the right choice of diodes. For use in the power supply, elements with reverse current indicators are up to 10 amperes. The number of diodes is 4, and they should be installed according to the bridge type. If you apply the diagram on one semiconductor, the beneficial effect of the block is reduced by half.

This is important: it is forbidden to work with electric elements that are energized. Before making any manipulations, you need to make sure that the device is disconnected from the network.

Alteration of an electronic transformer for an electric screwdriver

Many had old screwdrivers with nickel cadmium batteries, it is a pity to throw them out, and buying new batteries quite expensive dimensional expensive. But at the same time, lying around idle, they will not bring any benefit. There is an idea to transfer them to network power.

I previously collected a powerful power source for an electric screwdriver based on an electronic transformer, this time I decided to make a power supply on IR2153.

This is a classic semi.milk scheme. The IR2153 chip is taken from a variable line, extinguished by a resistor, straightened, filtered and enters the microcircuit.

Power keys in my case. These are high-voltage N-channel field transistors 10N60, 600 volts 10 amperes.

The output rectifier is a single.polar with a middle point, built on a 45 volt diode assembly and 30 amperes, enough with the head.

At the exit, after the rectifier there are a pair of capacitors by 35 volts, in principle, a large container is not needed, but it is advisable to take them with low internal resistance.

The transformer can be taken ready, from any computer power supply, in the Noah, I dug up such

You can use elongated transformers, these are often placed in the ath450 watt blocks, they also do not need to rewind them, standard windings will allow obtaining voltage at the outlet of about 12-15 volts.

In my case, problems arose as I forgot vertically mirror the transformer on the board template, and when I already noticed, the fee was etched, and the floor of the scheme was collected. I rewind the transformer, heated with a soldering iron for about 10 minutes, then gently dismantled the core, removed all the standard windings and wound up new.

In the case of using transformers of the same size from computer PSU and taking into account the operating frequency of the IR2153 chip, the primary winding contains about 40 turns with wire 0.8 mm, the secondary winding is wound with a calculation of 1 round 3-3.5 volts, in my case I wound 2 each 5 turns, the output voltage turned out about 17 volts, but there will be slightly less under load. The diameter of the wire of the winding is 1.2mm, this is enough to get a decent current at the output.

An example of calculating a pulsed transformer

I tried to make a scarf as compact as possible, it should easily get into the building of the 18 volt nickel cadmium battery of an electric screwdriver, but it may have to be lightly tuned to the scarf.

The assembled power supply can give a power of about 200-250 watts to the load, and if you use an elongated transformer, you can pump out much more from the block.

An electric screwdriver can consume huge currents of 20-30 and even 40 amperes from the battery, if the cartridge is completely stopped. The assembled power supply does not have protection and with hard overloads may not withstand. I strongly recommend the rattle on the electric screwdriver itself never to install in the maximum effort, this is very important, the rattle is protection.

Currently cooling the power supply is not so hot, transistors and diode must be installed on radiators, and in the case of the battery itself, drill holes for air cooling.

To reduce the overall dimensions of the power source, I excluded the input and output filters, since we have a load of an electric screwdriver, and not a power amplifier or other sensitive device.

Half.month capacitors for 200.250 volts, capacity from 220 to 470MKF, each capacitor is made by the aligning resistor, which simultaneously discharge them after turning off the unit from the network. Such capacitors can also be torn from computer power supply units.

Any field transistors with a current of 7 amperes for a voltage of 500-600 volts, try to choose the keys with a small shutter capacity and the resistance of the open channel, they will be easier to control and warm them less.

It is advisable to take a film dividing capacitor with a capacity of 1-1.5MKF with a calculated voltage of 400 volts, in extreme cases 250V.

The output rectifier. This is a powerful double diode, these can be found in computer power supplies, the return voltage of the assembly is 40-45 volts, the current the more, the better.