How to make an ice driver from a fluorescent lamp. Switching power supply from an energy-saving lamp. High power power supply unit

The failure of the battery of a cordless screwdriver or other power tool is not the most pleasant event, especially when you consider that the cost of replacing this element is commensurate with the price of a new device. But maybe unplanned expenses can be avoided? This is quite possible if you replace the battery with a simple home-made energy-saving pulse-type power supply, with which the tool can be charged from the mains. And components for it can be found in an affordable and ubiquitous product - this.

Energy Saving Bulb Ballast Source

DIY fluorescent lamp UPS

In most cases, to assemble a UPS, the EPRA electronic choke should only be slightly changed (with a two-transistor circuit) by means of a jumper, and then connected to a pulse transformer and a rectifier. Some components are simply removed as unnecessary.

Homemade power supply

For weak power supplies (from 3.7 V to 20 watts), you can do without a transformer. It will be enough to add a few turns of wire to the magnetic circuit of the choke available in the ballast of the lamp, if, of course, there is a place for this. A new winding can be done directly over the existing one.

For this, a wire of the MGTF brand with fluoroplastic insulation is perfect. Usually, few wires are required, while almost the entire lumen of the magnetic circuit is occupied by insulation, which determines the low power of such devices. To increase it, you need a pulse transformer.

Pulse transformer

A feature of the described version of the UPS is the ability to some extent adapt to the parameters of the transformer, as well as the absence of a feedback circuit passing through this element. Such a connection scheme makes it possible to do without a particularly accurate calculation of the transformer.

As practice has shown, even with gross errors (deviations of more than 140% were allowed), the UPS can be given a second life and it turned out to be efficient.

The transformer is made on the basis of the same choke, on which the secondary winding is wound from a varnished winding copper wire. In this case, it is important to pay special attention to the interwinding insulation made of paper gasket, because the "native" winding of the choke will operate under mains voltage.

Even if it is covered with a synthetic protective film, it is still necessary to wind several layers of electric cardboard or at least ordinary paper with a total thickness of 100 microns (0.1 mm) on top of it, and a varnished wire of a new winding can be laid on top of the paper.

The wire diameter should be as large as possible. There will not be many turns in the secondary winding, so their optimal number can be selected empirically.

Using these materials and technology, you can get a power supply unit with a power of 20 watts or a little more. In this case, its value is limited by the area of ​​the magnetic circuit window and, accordingly, by the maximum diameter of the wire that can be placed there.

Rectifier

To avoid saturation of the magnetic circuit, only full-wave output rectifiers are used in the UPS. In the event that a pulse transformer operates to lower the voltage, the most economical circuit is with a zero point, but for its implementation it will be necessary to make two completely symmetrical secondary windings. With manual winding, you can wind it in two wires.

A standard rectifier, assembled according to the "diode bridge" scheme from conventional silicon diodes, is not suitable for a switching UPS, since out of 100 W of transmitted power (at a voltage of 5 V), it will lose about 32 W or more. It will be too expensive to assemble a rectifier on powerful pulse diodes.

Setting up the UPS

After assembling the UPS, it must be connected to the maximum load and check how hot the transistors and the transformer are. The limit for a transformer is 60 - 65 degrees, for transistors - 40 degrees. When the transformer overheats, the wire cross-section or the overall power of the magnetic circuit is increased, or both actions are performed together. If the transformer is made from a lamp ballast choke, it is most likely that it will not work to increase the wire cross-section and you will have to limit the connected load.

How to make an LED PSU with increased power

Sometimes the standard power of the electronic lamp ballast is not enough. Imagine a situation: you have 23 W, and you need to get a power supply for a charger with 12V / 8A parameters.

In order to implement our plan, you will have to get a computer power supply, which for some reason turned out to be unclaimed. The power transformer should be removed from this block along with the R4C8 chain, which performs the function of protecting power transistors from overvoltage. The power transformer should be connected to an electronic ballast instead of a choke.

It was experimentally found that this type of UPS can remove power up to 45 W with a slight overheating of transistors (up to 50 degrees).

To avoid overheating, it is necessary to install a transformer with an enlarged core section in the bases of the transistors, and install the transistors themselves on the radiator.

Possible mistakes

As already mentioned, the inclusion of a conventional low-frequency diode bridge as an output rectifier in the circuit is impractical, and with increased power of the UPS, this is all the more not worth doing.

It is also pointless to try for the sake of simplifying the circuit to wind the base windings directly on the power transformer. In the absence of a load, significant losses will occur due to the fact that a maximum current will flow into the bases of the transistors.

The applied transformer with an increase in the load current also increases the current in the bases of the transistors. Practice shows that when the load power reaches 75 W, saturation occurs in the magnetic circuit of the transformer. This leads to a deterioration in the characteristics of transistors and their overheating.

To avoid this, you can wind the current transformer yourself, doubling the cross-section of the core or putting two rings together. You can also double the wire diameter.

There is a way to get rid of the base transformer that serves the intermediate function. For this, the current transformer is connected through a power resistor to a separate winding of the power heater, realizing a voltage feedback circuit. The disadvantage of this option is that the current transformer is constantly operating in saturation mode.

Do not connect the transformer in parallel with the choke in the ballast converter. Due to the decrease in the total inductance, the frequency of the power supply will be increased. Such a phenomenon will lead to an increase in losses in the transformer and overheating of the transistors of the output rectifier.

Consideration should be given to the increased sensitivity of Schottky diodes to exceeding the reverse voltage and current values. Attempting to install, say, a 5-volt diode into a 12-volt circuit is likely to damage the cell.

Do not try to replace transistors and diodes with domestic ones, for example, KT812A and KD213. This will unambiguously lead to a deterioration in the performance of the device.

How to connect the UPS to a screwdriver

The power tool must be disassembled by unscrewing all screws. Typically, a screwdriver body consists of two halves. Next, you should find the wires that connect the engine to the battery. You can connect these wires to the UPS output using soldering or heat shrink tubing, the twisted option is undesirable.

To enter the wire from the power supply, a hole must be made in the tool body. It is important to provide measures to prevent the wire from being pulled out in case of careless movements or accidental jerks. The easiest option is to crimp the wire inside the case at the very hole with a clip from a short piece of soft wire folded in half (aluminum is suitable). Having dimensions exceeding the diameter of the hole, the clip will not allow the wire to come off and fall out of the case in case of a jerk.

As you can see, an energy-saving light bulb, even after its expiration date, can bring considerable benefit to its owner. The UPS assembled on the basis of its components can be successfully used as a source of energy for a cordless power tool or charger.

Video

This video will tell you how to assemble a power supply unit (PSU) from energy-saving lamps.

Due to their low power consumption, theoretical durability and price reduction, incandescent and energy-saving lamps are rapidly replacing. But, despite the declared service life of up to 25 years, they often burn out without even having served the warranty period.

Unlike incandescent bulbs, 90% of burnt-out LED bulbs can be successfully repaired with your own hands, even without special training. The examples provided will help you repair a failed LED lamp.

Before undertaking the repair of an LED lamp, you need to present its device. Regardless of the appearance and type of LEDs used, all LED lamps, including filament bulbs, have the same structure. If you remove the walls of the lamp housing, then inside you can see the driver, which is a printed circuit board with radio elements installed on it.

Any LED lamp is arranged and works as follows. The supply voltage from the contacts of the electric cartridge is applied to the terminals of the base. Two wires are soldered to it, through which voltage is applied to the driver input. From the driver, the DC supply voltage is supplied to the board on which the LEDs are soldered.

The driver is an electronic unit - a current generator that converts the supply voltage into the current required for the LEDs to glow.

Sometimes, to diffuse light or protect against human contact with the unprotected conductors of the board with LEDs, it is covered with a diffusing protective glass.

About filament lamps

In appearance, a filament lamp is similar to an incandescent lamp. The device of filament lamps differs from LED lamps in that they use not a board with LEDs as light emitters, but a glass sealed gas-filled bulb in which one or more filament rods are placed. The driver is located in the base.

The filament rod is a glass or sapphire tube with a diameter of about 2 mm and a length of about 30 mm, on which 28 miniature LEDs coated with a phosphor are fixed and connected in series. One filament consumes about 1 W of power. My operating experience shows that filament lamps are much more reliable than those made with SMD LEDs. I suppose over time they will replace all other artificial light sources.

Examples of repairing LED lamps

Attention, the electrical circuits of the LED lamp drivers are galvanically connected to the mains phase and therefore care should be taken. Touching exposed circuitry while connected to the mains can result in electric shock.

LED lamp repair
ASD LED-A60, 11 W on the SM2082 chip

Currently, powerful LED bulbs have appeared, the drivers of which are assembled on microcircuits of the SM2082 type. One of them worked for less than a year and was repaired to me. The light bulb went out haphazardly and then turned on again. When tapped on it, it responded with light or extinguishing. It became apparent that the problem was a poor connection.

To get to the electronic part of the lamp, you need to pick up the diffusing glass with a knife at the point of contact with the body. Sometimes it is difficult to separate the glass, since silicone is applied to the fixing ring when it is seated.

After removing the light-scattering glass, access to the LEDs and a microcircuit - the SM2082 current generator was opened. In this lamp, one part of the driver was mounted on an aluminum LED PCB, and the other on a separate one.

External examination did not reveal defective rations or track breaks. I had to remove the board with LEDs. To do this, the silicone was first cut off and the board was pried over the edge with a screwdriver blade.

To get to the driver located in the lamp housing, it was necessary to unsolder it, warming up two contacts with a soldering iron at the same time and moving it to the right.

On one side of the driver PCB, only a 6.8 μF 400 V electrolytic capacitor was installed.

On the reverse side of the driver board, a diode bridge and two series-connected resistors with a nominal value of 510 kOhm were installed.

In order to figure out which of the boards the contact is missing, they had to be connected, observing the polarity, using two wires. After tapping on the boards with the handle of a screwdriver, it became obvious that the malfunction lies in the board with the capacitor or in the contacts of the wires coming from the base of the LED lamp.

Since the soldering was not suspicious, I first checked the reliability of the contact in the central outlet of the base. It can be easily removed if you pry it over the edge with a knife blade. But the contact was reliable. Just in case, I tinned the wire with solder.

It is difficult to remove the screw part of the base, so I decided to solder the soldering wires from the base with a soldering iron. When touching one of the rations, the wire was exposed. There was a "cold" soldering. Since it was not possible to get to the wire for stripping, it was necessary to lubricate it with active flux "FIM", and then re-solder it.

Once assembled, the LED lamp emitted light steadily despite being hit by a screwdriver handle. Checking the luminous flux for pulsations showed that they are significant at a frequency of 100 Hz. Such an LED lamp can only be installed in luminaires for general lighting.

Driver wiring diagram
LED lamp ASD LED-A60 on a chip SM2082

The electrical circuit of the ASD LED-A60 lamp, thanks to the use of a specialized microcircuit SM2082 in the driver for stabilizing the current, turned out to be quite simple.

The driver circuit works as follows. The AC supply voltage is fed through the fuse F to the rectifier diode bridge assembled on the MB6S microassembly. The electrolytic capacitor C1 smooths out the ripple, and R1 serves to discharge it when the power is turned off.

From the positive terminal of the capacitor, the supply voltage is applied directly to the series-connected LEDs. From the output of the last LED, the voltage is applied to the input (pin 1) of the SM2082 microcircuit, the current in the microcircuit is stabilized and then from its output (pin 2) is fed to the negative terminal of the capacitor C1.

Resistor R2 sets the amount of current flowing through the HL LEDs. The magnitude of the current is inversely proportional to its rating. If the value of the resistor is reduced, then the current will increase, if the value is increased, then the current will decrease. The SM2082 microcircuit allows the resistor to adjust the current value from 5 to 60 mA.

LED lamp repair
ASD LED-A60, 11W, 220V, E27

Another ASD LED-A60 LED lamp, similar in appearance and with the same technical characteristics as the repaired one above, got into the repair.

When turned on, the lamp ignited for a moment and did not shine further. This behavior of LED lamps is usually associated with a driver malfunction. Therefore, I immediately proceeded to disassemble the lamp.

The light-scattering glass was removed with great difficulty, since along the entire line of contact with the body, despite the presence of a retainer, it was abundantly lubricated with silicone. To separate the glass, I had to look for a pliable place along the entire line of contact with the body with a knife, but still, there was a crack in the body.

To gain access to the lamp driver, the next step was to remove the LED printed circuit board, which was pressed along the contour into an aluminum insert. Despite the fact that the board was aluminum, and it was possible to remove it without fear of cracks, all attempts were unsuccessful. The board was kept tight.

It also did not work to remove the board together with the aluminum insert, since it fit snugly to the case and was seated with the outer surface on silicone.

I decided to try to take out the driver board from the side of the base. To do this, first, a knife was pried out of the base with a knife, and the central contact was removed. To remove the threaded part of the base, it was necessary to slightly bend its upper flange so that the punching points disengage from the base.

The driver became available and moved freely to a certain position, but it was not possible to completely remove it, although the conductors from the LED board were sealed off.

There was a hole in the center of the LED board. I decided to try to remove the driver board by striking its end through a metal rod threaded through this hole. The board has advanced a few centimeters and bumped into something. After further blows, the lamp body cracked in the ring and the board with the base of the base detached.

As it turned out, the board had an extension, which with its shoulders rested against the lamp body. It looks like the board was shaped to restrict movement, although it was enough to fix it with a drop of silicone. Then the driver would be removed from either side of the lamp.

The voltage of 220 V from the lamp base through a resistor - the FU fuse is fed to the MB6F rectifier bridge and after it is smoothed by an electrolytic capacitor. Further, the voltage is fed to the SIC9553 microcircuit, which stabilizes the current. Parallel connected resistors R20 and R80 between pins 1 and 8 of the MS set the value of the LED supply current.

The photo shows a typical electrical schematic diagram given by the manufacturer of the SIC9553 chip in a Chinese datasheet.

This photo shows the appearance of the LED lamp driver from the side of the installation of the output elements. Since space allowed, to reduce the ripple factor of the luminous flux, the capacitor at the driver output was soldered to 6.8 uF instead of 4.7 uF.

If you have to remove the drivers from the body of this lamp model and you cannot remove the LED board, you can use a jigsaw to cut the lamp body around the circumference just above the screw part of the base.

In the end, all my efforts to extract the driver turned out to be useful only for the knowledge of the LED lamp design. The driver was found to be working properly.

The flash of the LEDs at the moment of switching on was caused by a breakdown in the crystal of one of them as a result of a voltage surge when the driver was started, which misled me. First of all, it was necessary to ring the LEDs.

An attempt to test the LEDs with a multimeter was unsuccessful. The LEDs were off. It turned out that two light-emitting crystals connected in series are installed in one case, and in order for the LED to start flowing current, it is necessary to apply a voltage of 8 V.

A multimeter or tester, included in the resistance measurement mode, produces a voltage within 3-4 V. I had to check the LEDs using a power supply, supplying 12 V to each LED through a 1 kOhm current-limiting resistor.

There was no replacement LED available, so a drop of solder shorted the pads instead. It is safe for the driver to work, and the power of the LED lamp will decrease by only 0.7 W, which is almost imperceptible.

After repairing the electrical part of the LED lamp, the cracked body was glued with quick-drying superglue "Moment", the seams were smoothed by melting the plastic with a soldering iron and leveled with sandpaper.

For interest, I did some measurements and calculations. The current flowing through the LEDs was 58 mA, the voltage was 8 V. Therefore, the power supplied to one LED is 0.46 W. With 16 LEDs, it turns out 7.36 watts, instead of the declared 11 watts. Perhaps the manufacturer indicated the total power consumption of the lamp, taking into account the losses in the driver.

The service life of the LED lamp ASD LED-A60, 11 W, 220 V, E27, declared by the manufacturer, raises my doubts. In a small volume of a plastic lamp body, with a low thermal conductivity, significant power is released - 11 watts. As a result, the LEDs and the driver operate at the maximum permissible temperature, which leads to accelerated degradation of their crystals and, as a consequence, to a sharp decrease in their MTBF.

LED lamp repair
LED smd B35 827 ERA, 7 W on a BP2831A chip

An acquaintance shared with me that he bought five bulbs as in the photo below, and all of them stopped working after a month. He managed to throw out three of them, and he brought two, at my request, for repair.

The light worked, but instead of bright light, it emitted a flickering faint light with a frequency of several times per second. I immediately assumed that the electrolytic capacitor had swollen, usually if it fails, then the lamp begins to emit light, like a stroboscope.

The light-scattering glass was removed easily, it was not glued. It was fixed by means of a slot on its rim and a protrusion in the lamp housing.

The driver was secured with two solders to a PCB with LEDs, as in one of the above lamps.

A typical driver circuit on the BP2831A microcircuit taken from the datasheet is shown in the photo. The driver board was removed and all simple radio elements were checked, everything turned out to be in good order. I had to start checking the LEDs.

The LEDs in the lamp were installed of an unknown type with two crystals in the case and inspection did not reveal any defects. Using the method of serially connecting the leads of each of the LEDs, I quickly identified the faulty one and replaced it with a drop of solder, as in the photo.

The light bulb worked for a week and was repaired again. Shorted out the next LED. A week later, I had to short-circuit another LED, and after the fourth I threw out the light bulb, as I was tired of repairing it.

The reason for the failure of bulbs of this design is obvious. LEDs overheat due to insufficient heat sink surface, and their resource is reduced to hundreds of hours.

Why is it permissible to short-circuit the leads of burned-out LEDs in LED lamps

The driver of LED lamps, unlike a constant voltage power supply, outputs a stabilized current value at the output, not a voltage. Therefore, regardless of the load resistance within the specified limits, the current will always be constant and, therefore, the voltage drop across each of the LEDs will remain the same.

Therefore, with a decrease in the number of series-connected LEDs in the circuit, the voltage at the driver output will also decrease proportionally.

For example, if 50 LEDs are connected in series to the driver, and a voltage of 3 V drops on each of them, then the voltage at the driver output was 150 V, and if 5 of them are short-circuited, the voltage will drop to 135 V, and the current will not change.

But the efficiency (efficiency) of the driver assembled according to such a scheme will be low and the power loss will be more than 50%. For example, for an MR-16-2835-F27 LED bulb, you need a 6.1 kΩ resistor with a power of 4 watts. It turns out that the driver on the resistor will consume power exceeding the power consumption of the LEDs and it will be unacceptable to place it in a small case of the LED lamp, due to the release of more heat.

But if there is no other way to repair the LED lamp and it is very necessary, then the driver on the resistor can be placed in a separate case, all the same, the power consumption of such an LED lamp will be four times less than that of an incandescent lamp. It should be noted that the more LEDs connected in series in the bulb, the higher the efficiency will be. With 80 series-connected SMD3528 LEDs, you will need an 800 Ohm resistor with a power of only 0.5 W. The capacitance of C1 will need to be increased to 4.7 µF.

Finding faulty LEDs

After removing the protective glass, it becomes possible to check the LEDs without peeling off the printed circuit board. First of all, a careful examination of each LED is carried out. If even the smallest black dot is found, not to mention the blackening of the entire surface of the LED, then it is definitely faulty.

When examining the appearance of LEDs, you need to carefully examine the quality of the rations of their conclusions. In one of the bulbs being repaired, there were four LEDs poorly soldered at once.

The photo shows a light bulb that had very small black dots on its four LEDs. I immediately marked the faulty LEDs with crosses so that they could be clearly seen.

Defective LEDs may or may not have a change in appearance. Therefore, it is necessary to check each LED with a multimeter or a pointer tester, included in the resistance measurement mode.

There are LED lamps in which standard LEDs are installed in appearance, in the case of which two crystals connected in series are mounted at once. For example, lamps of the ASD LED-A60 series. For continuity of such LEDs, it is necessary to apply a voltage of more than 6 V to its terminals, and any multimeter outputs no more than 4 V. Therefore, such LEDs can be checked only by applying a voltage of more than 6 (recommended 9-12) V to them from a power source through a 1 kΩ resistor ...

The LED is checked, like a regular diode, in one direction the resistance should be equal to tens of megohms, and if you swap the probes (this changes the polarity of the voltage supply to the LED), then small, while the LED may glow dimly.

When checking and replacing LEDs, the lamp must be fixed. You can use a suitable sized round jar for this.

It is possible to check the health of the LED without an additional constant current source. But this verification method is possible if the light bulb driver is working properly. To do this, it is necessary to apply a supply voltage to the base of the LED light bulb and the terminals of each LED should be sequentially short-circuited with a jumper from a wire or, for example, with jaws of metal tweezers.

If suddenly all the LEDs light up, it means that the shorted one is definitely faulty. This method is useful if only one of the LEDs in the circuit is faulty. With this method of verification, it must be taken into account that if the driver does not provide galvanic isolation from the mains, as, for example, in the above diagrams, then touching the LED solders with your hand is unsafe.

If one or even several LEDs turned out to be faulty and there is nothing to replace them with, then you can simply short-circuit the contact pads to which the LEDs were soldered. The light bulb will work with the same success, only the luminous flux will decrease slightly.

Other malfunctions of LED lamps

If the check of the LEDs showed their serviceability, then the reason for the inoperability of the light bulb is in the driver or in the soldering points of the current-carrying conductors.

For example, a cold soldering conductor was found in this light bulb, supplying power to the printed circuit board. The soot released from poor soldering even settled on the conductive paths of the printed circuit board. The soot was easily removed by wiping with a cloth soaked in alcohol. The wire was soldered, stripped, tinned and re-soldered into the board. We were lucky with the repair of this light bulb.

Of ten failed bulbs, only one had a faulty driver, a diode bridge collapsed. The driver repair consisted in replacing the diode bridge with four IN4007 diodes, designed for a reverse voltage of 1000 V and a current of 1 A.

Soldering SMD LEDs

To replace a faulty LED, it must be evaporated without damaging the printed conductors. You also need to remove the replacement LED from the donor board without damage.

It is almost impossible to solder SMD LEDs with a simple soldering iron without damaging their case. But if you use a special tip for a soldering iron or put on a nozzle made of copper wire on a standard tip, then the problem is easily solved.

The LEDs are polarized and must be correctly installed on the PCB when replacing. Typically, the printed conductors follow the shape of the LED leads. Therefore, you can only make a mistake with carelessness. To seal the LED, it is enough to install it on the printed circuit board and warm it up with a 10-15 W soldering iron with its ends with contact pads.

If the LED is burnt to charcoal, and the printed circuit board underneath is charred, then before installing a new LED, it is imperative to clean this place of the printed circuit board from burning, since it is a current conductor. When cleaning, you may find that the solder pads for the LED are burnt or peeled off.

In this case, the LED can be installed by soldering it to adjacent LEDs if the printed paths lead to them. To do this, you can take a piece of thin wire, bend it in half or three, depending on the distance between the LEDs, tin and solder to them.

Repair of LED lamp series "LL-CORN" (corn lamp)
E27 4.6W 36x5050SMD

The device of the lamp, which is popularly called the corn lamp, shown in the photo below, is different from the lamp described above, therefore the repair technology is different.

The design of lamps on LED SMD of this type is very convenient for repair, since there is access for the continuity of the LEDs and their replacement without disassembling the lamp body. True, I disassembled the light bulb anyway for interest, in order to study its structure.

Checking the LEDs of the LED corn lamp does not differ from the technology described above, but it must be taken into account that three LEDs are located in the SMD5050 LED case, usually connected in parallel (three dark dots of crystals are visible on the yellow circle), and all three should light up during the check.

A defective LED can be replaced with a new one or by a jumper. This will not affect the reliability of the lamp, only imperceptibly to the eye, the luminous flux will decrease slightly.

The driver of this lamp is assembled according to the simplest scheme, without an isolation transformer, therefore, touching the LED terminals with the lamp on is unacceptable. Lamps of this design must not be installed in luminaires that can be accessed by children.

If all the LEDs are in good working order, then the driver is faulty, and in order to get to it, the lamp will have to be disassembled.

To do this, you need to remove the bezel from the side opposite to the base. Using a small screwdriver or a knife blade, you need to try in a circle to find the weak spot where the rim is worst glued. If the bezel gives in, then working with a tool, like a lever, the bezel will easily move away around the entire perimeter.

The driver was assembled according to the electrical circuit, like that of the MR-16 lamp, only C1 was 1 µF, and C2 was 4.7 µF. Due to the fact that the wires leading from the driver to the lamp base were long, the driver was easily pulled out of the lamp housing. After studying its circuit, the driver was inserted back into the case, and the bezel was glued in place with transparent glue "Moment". The failed LED is replaced with a good one.

Repair of LED lamp "LL-CORN" (corn lamp)
E27 12W 80x5050SMD

When repairing a more powerful lamp, 12 W, the same design of failed LEDs was not found, and in order to get to the drivers, I had to open the lamp using the technology described above.

This lamp gave me a surprise. The wires leading from the driver to the base turned out to be short, and it was impossible to remove the driver from the lamp housing for repair. I had to remove the base.

The lamp base was made of aluminum, nibbled around the circumference and held firmly. I had to drill the attachment points with a 1.5 mm drill. After that, the base, which had been pushed with a knife, was easily removed.

But you can do without drilling the base if you pry and slightly bend its upper edge with the edge of a knife around the circumference. Beforehand, a mark should be made on the plinth and the casing so that the plinth can be conveniently installed in place. To securely fix the base after repairing the lamp, it will be enough to put it on the lamp body in such a way that the punched points on the base fall into the old places. Then push through these points with a sharp object.

Two wires were connected to the thread with a clamp, and the other two were pressed into the central contact of the base. I had to eat these wires.

As expected, the drivers were two identical, supplying 43 diodes each. They were covered with a heat-shrinkable tube and taped together. In order for the driver to fit back into the tube, I usually cut it neatly along the PCB on the side where the parts are to be installed.

After repair, the driver is wrapped in a tube, which is fixed with a plastic tie or wrapped in several turns of thread.

In the electrical circuit of the driver of this lamp, protection elements are already installed, C1 for protection against impulse surges and R2, R3 for protection against current surges. When checking the elements, resistors R2 were immediately found on both drivers in the open circuit. It looks like an over-voltage was applied to the LED lamp. After replacing the resistors, there was no 10 Ohm at hand, and I set it to 5.1 Ohm, the lamp worked.

Repair of LED lamp series "LLB" LR-EW5N-5

The appearance of this type of light bulb inspires confidence. Aluminum body, high quality workmanship, beautiful design.

The design of the light bulb is such that disassembling it without significant physical effort is impossible. Since the repair of any LED lamp begins with checking the health of the LEDs, the first thing that had to be done was to remove the plastic protective glass.

The glass was fixed without glue on a groove made in the radiator with a bead inside it. To remove the glass, you need to use the end of a screwdriver that will pass between the fins of the radiator, lean on the end of the radiator and, like a lever, lift the glass up.

Checking the LEDs with a tester showed their serviceability, therefore, the driver is faulty, and you need to get to it. The aluminum board was secured with four screws, which I unscrewed.

But contrary to expectations, behind the board was the heatsink plane, smeared with heat-conducting paste. The board had to be returned to its place and continued to disassemble the lamp from the base side.

Due to the fact that the plastic part, to which the radiator was attached, held very tightly, I decided to go the proven way, remove the base and remove the driver through the opened hole for repair. I drilled out the punching spots, but the base was not removed. It turned out that he still held on to the plastic due to the threaded connection.

I had to separate the plastic adapter from the radiator. He held on, just like the protective glass. For this, it was washed down with a hacksaw for metal at the junction of the plastic with the radiator and by turning a screwdriver with a wide blade, the parts were separated from each other.

After unsoldering the leads from the LED printed circuit board, the driver became available for repair. The driver circuit turned out to be more complex than previous bulbs, with an isolation transformer and a microcircuit. One of the 400 V 4.7 µF electrolytic capacitors was swollen. I had to replace him.

Checking all the semiconductor elements revealed a faulty D4 Schottky diode (pictured below left). On the board there was a Schottky diode SS110, replaced by the existing analogue 10 BQ100 (100 V, 1 A). The forward resistance of Schottky diodes is half that of ordinary diodes. The LED light is on. The second light bulb had the same malfunction.

Repair of LED lamp series "LLB" LR-EW5N-3

This LED lamp is very similar in appearance to the "LLB" LR-EW5N-5, but the design is slightly different.

If you look closely, you can see that at the junction between the aluminum radiator and the spherical glass, unlike the LR-EW5N-5, there is a ring in which the glass is fixed. To remove the protective glass, it is enough to pick it up with a small screwdriver at the junction with the ring.

The aluminum PCB contains three nine super-bright crystal LEDs. The board is screwed to the heatsink with three screws. Checking the LEDs showed their serviceability. Hence, the driver needs to be repaired. Having experience in repairing a similar LED lamp "LLB" LR-EW5N-5, I did not unscrew the screws, but unsoldered the lead wires coming from the driver and continued to disassemble the lamp from the base side.

The plastic connecting ring between the base / plinth and the radiator was removed with great difficulty. At the same time, part of it broke off. As it turned out, it was screwed to the radiator with three self-tapping screws. The driver was easily removed from the lamp housing.

The self-tapping screws screwing the plastic ring of the base cover the driver, and it is difficult to see them, but they are on the same axis with the thread to which the transitional part of the radiator is screwed. Therefore, you can get to them with a thin Phillips screwdriver.

The driver was assembled according to a transformer circuit. Checking all the elements, except for the microcircuit, did not reveal the failed ones. Therefore, the microcircuit is faulty, I did not even find a mention of its type on the Internet. The LED light bulb could not be repaired, it will come in handy for spare parts. But I studied her device.

Repair of LED lamp series "LL" GU10-3W

At first glance, it turned out to be impossible to disassemble a burnt-out GU10-3W LED bulb with protective glass. An attempt to remove the glass led to its chipping. When applied with great effort, the glass cracked.

By the way, in the marking of the lamp, the letter G means that the lamp has a pin base, the letter U, that the lamp belongs to the class of energy-saving bulbs, and the number 10 is the distance between the pins in millimeters.

LED bulbs with GU10 base have special pins and are installed in the socket with a twist. Thanks to the expanding pins, the LED lamp is pinched in the holder and is securely held even when shaken.

In order to disassemble this LED bulb, we had to drill a hole with a diameter of 2.5 mm in its aluminum case at the level of the surface of the printed circuit board. The place of drilling must be chosen in such a way that the drill does not damage the LED when exiting. If you do not have a drill at hand, then the hole can be made with a thick awl.

Next, a small screwdriver is threaded into the hole and, acting like a lever, the glass is lifted. I removed glass from two bulbs without any problems. If the test of the LEDs with a tester showed their serviceability, then the printed circuit board is removed.

After separating the board from the lamp body, it immediately became obvious that both in one and in the other lamp, the current-limiting resistors burned out. The calculator determined their nominal value by the bands, 160 ohms. Since the resistors burned out in LED bulbs of different batches, it is obvious that their power, judging by the size of 0.25 W, does not correspond to the power released when the driver is operating at the maximum ambient temperature.

The driver's PCB was solidly sealed with silicone, and I didn't disconnect it from the LED board. I cut off the leads of the burned-out resistors at the base and soldered more powerful resistors to them, which were at hand. In one lamp, a 150 Ohm resistor with a power of 1 W was soldered, in the second two parallel 320 Ohm with a power of 0.5 W.

In order to exclude accidental touching of the resistor terminal, to which the mains voltage with the metal lamp housing is suitable, it was insulated with a drop of hot melt glue. It is waterproof, excellent insulator. I often use it for sealing, insulating and securing electrical wires and other parts.

Hot melt glue is available in the form of rods with a diameter of 7, 12, 15 and 24 mm in different colors, from transparent to black. It melts, depending on the brand, at a temperature of 80-150 °, which allows it to be melted using an electric soldering iron. It is enough to cut off a piece of the rod, place it in the right place and heat it up. The hot melt glue will acquire the consistency of honey in May. After cooling, it becomes solid again. When reheated, it becomes liquid again.

After replacing the resistors, the performance of both bulbs was restored. It remains only to fix the PCB and protective glass in the lamp housing.

When repairing LED bulbs, I used "Montage" liquid nails to secure the PCBs and plastic parts in place. Odorless glue, adheres well to the surfaces of any materials, remains plastic after drying, has sufficient heat resistance.

It is enough to take a small amount of glue on the end of the screwdriver and apply it to the contact points of the parts. After 15 minutes, the glue will already hold.

When gluing the printed circuit board, in order not to wait, holding the board in place, since the wires pushed it out, I fixed the board additionally at several points with hot glue.

The LED lamp started flashing like a strobe

I had to repair a couple of LED lamps with drivers assembled on a microcircuit, the malfunction of which was the blinking of light with a frequency of about one hertz, like in a stroboscope.

One copy of the LED lamp started blinking immediately after switching on for the first few seconds and then the lamp began to shine normally. Over time, the duration of the lamp blinking after turning on began to increase, and the lamp began to blink continuously. The second copy of the LED lamp began to flash continuously suddenly.

After disassembling the lamps, it turned out that the electrolytic capacitors installed immediately after the rectifier bridges in the drivers were out of order. It was easy to identify the fault as the capacitor housings were swollen. But even if in appearance the capacitor looks without external defects, then all the same, the repair of an LED light bulb with a stroboscopic effect must begin with its replacement.

After replacing the electrolytic capacitors with serviceable ones, the stroboscopic effect disappeared and the lamps began to shine normally.

Online calculators for determining the value of resistors
by color coding

When repairing LED lamps, it becomes necessary to determine the value of the resistor. According to the standard, marking of modern resistors is made by applying colored rings to their cases. 4 colored rings are applied to simple resistors, and 5 to high precision resistors.

Is it possible to make an LED lamp (LED) operating from a voltage of 220 volts with your own hands from start to finish? It turns out you can. Our tips and instructions will help you with this fun activity.

Benefits of LED bulbs

LED lighting in the home is not just modern, but also stylish and bright. Conservative fans of incandescent lamps remain weak "Ilyich's bulbs" - the Federal Law "On Energy Saving", adopted in 2009, from January 1, 2011, prohibits the production, import and sale of incandescent lamps with a capacity of more than 100 watts. Advanced users have long since switched to compact fluorescent lamps (CFLs). But LEDs bypass all of their predecessors:

• the power consumption of an LED lamp is 10 times less than that of a corresponding incandescent lamp, and almost 35% less than that of a CFL;
• the luminous intensity of the LED lamp is 8 and 36% higher, respectively;
• the achievement of the full power of the luminous flux occurs instantly, in contrast to CFLs, which take about 2 minutes;
• the cost - subject to the manufacture of the lamp independently - tends to zero;
• LED lamps are environmentally friendly because they do not contain mercury;
• the service life of LEDs is measured in tens of thousands of hours. Therefore, LED lamps are practically eternal.

Dry numbers confirm: LED is the future.

The design of a modern factory LED lamp

The LED here was originally assembled from many crystals. Therefore, in order to assemble such a lamp, you do not need to solder numerous contacts, you only need to connect one pair.

The LED lamp consists of a base, a driver, a heat sink, the LED itself and a diffuser.

LED types

LED is a semiconductor multilayer crystal with an electron-hole junction. Passing a direct current through it, we receive light radiation. The LED also differs from a conventional diode in that, if connected incorrectly, it immediately burns out, since it has a low breakdown voltage (several volts). If the LED burns out, it must be completely replaced; repair is impossible.

There are four main types of LEDs:

A homemade and properly assembled LED lamp will serve for many years, while it can be repaired.

Before you start assembling yourself, you need to choose a power supply method for our future lamp. There are many options: from a battery to a 220 volt alternating current network - through a transformer or directly.

The easiest way is to assemble a 12-volt LED from a burnt-out "halogen". But it will require a fairly massive external power supply. A lamp with a conventional base, designed for a voltage of 220 volts, fits any cartridge in the house.

Therefore, in our guide, we will not consider the creation of a 12-volt LED light source, but show a couple of options for designing a 220-volt lamp.

Since we do not know the level of your electrical training, we cannot guarantee that you will get a properly working device at the output. In addition, you will be working with life-threatening voltages, and if anything is done inaccurately and incorrectly, damage and damage may occur, for which we will not be held responsible. Therefore, be careful and attentive. And you will succeed.

Drivers for LED lamps

The brightness of the LEDs directly depends on the strength of the current passing through them. For stable operation, they need a constant voltage source and a stabilized current that does not exceed the maximum permissible value for them.

Resistors - current limiters - can be dispensed with only for low-power LEDs. You can simplify the simple calculation of the number and characteristics of resistors by finding an LED calculator on the network, in which not only data is output, but also a ready-made electrical diagram of the structure is created.

To power the lamp from the mains, you must use a special driver that converts the input alternating voltage into operating voltage for LEDs. The simplest drivers consist of a minimal number of parts: an input capacitor, a few resistors, and a diode bridge.

In the circuit of the simplest driver, through a limiting capacitor, the supply voltage is supplied to the rectifier bridge, and then to the lamp

Powerful LEDs are connected through electronic drivers that control and stabilize the current and have a high efficiency (90-95%). They provide a stable current even with sudden changes in the supply voltage in the network. Resistors cannot do this.

Consider the simplest and most commonly used drivers for LED lamps:

• the linear driver is very simple and is used for low (up to 100 mA) operating currents or in cases where the source voltage is equal to the voltage drop across the LED;
• the impulse step-down driver is more complicated. It allows power LEDs to be powered by a source of much higher voltage than necessary for their operation. Disadvantages: large size and electromagnetic interference generated by the choke;
• The pulse boost driver is used when the operating voltage of the LED is greater than the voltage received from the power supply. The disadvantages are the same as in the previous driver.

An electronic driver is always built into any 220-volt LED lamp to ensure optimal operation.

Most often, several faulty LED lamps are disassembled, burned-out LEDs and driver radio components are removed, and one new structure is mounted from the whole.

But you can make an LED lamp from a regular CFL. This is quite an attractive idea. We are sure that many zealous owners still have faulty energy-saving boxes in their boxes with parts and spare parts. It's a pity to throw it away, there is nowhere to apply. Now we will tell you how to create an LED lamp from an energy-saving lamp (E27 base, 220 V) in just a couple of hours.

A defective CFL always gives us a high-quality base and housing for LEDs. In addition, it is the gas-discharge tube that usually fails, but not the electronic device for “igniting” it. We again put the existing electronics in the storeroom: it can be disassembled, and in skillful hands these parts will still serve something good.

Types of modern lamp bases

The base is a threaded system for quickly connecting and fixing the light source and the holder, supplying power to the source from the mains and ensuring the tightness of the vacuum flask. The plinth marking is deciphered as follows:

1. The first letter of the marking indicates the type of base:
   • B - with a pin;
   • E - threaded (developed back in 1909 by Edison);
   • F - with one pin;
   • G - with two pins;
   • H - for xenon;
   • K and R - respectively with cable and recessed contact;
   • P - focusing base (for spotlights and lanterns);
   • S - soffit;
   • T - telephone;
   • W - with contact leads in the glass of the flask.
2. The second letter U, A or V indicates in which lamps the base is used: in energy saving, automobile or with a tapered end.
3. The numbers following the letters indicate the diameter of the base in millimeters.

The most common base since Soviet times is considered to be the E27 - a threaded base with a diameter of 27 mm for a voltage of 220 V.

Creating an E27 LED lamp from an energy-saving lamp using a ready-made driver

To make an LED lamp ourselves, we need:

1. Failed CFL lamp.
2. Pliers.
3. Soldering iron.
4. Solder.
5. Cardboard.
6. Head on shoulders.
7. Skillful hands.

We will remake it under the LED faulty CFL of the Cosmos brand.

"Cosmos" is one of the most popular brands of modern energy-saving lamps, so many zealous owners will certainly have several faulty copies of it.

Step-by-step instructions for making an LED lamp

1. We find a faulty energy-saving lamp, which has been with us for a long time "just in case." Our lamp has a power of 20 watts. So far, the main component of interest to us is the base.
2. We carefully disassemble the old lamp and remove everything from it, except for the base and the wires coming from it, with which we will then solder the finished driver. The lamp is assembled using latches protruding above the body. You need to make out them and hook them with something. Sometimes the base is attached to the body more difficult - by punching dotted indentations around the circumference. Here you have to drill out the punching points or carefully saw them off with a hacksaw. One supply wire is soldered to the central contact of the base, the other to the thread. Both are very short. The tubes can burst during these manipulations, so you need to proceed with caution.
3. We clean the base and degrease it with acetone or alcohol. Increased attention should be paid to the hole, which is also thoroughly cleaned of excess solder. This is necessary for further soldering in the base.

   

   A trigger board for a gas discharge tube built into a fluorescent lamp will not work for us to create an LED device.

4. The cap of the base has six holes for the gas discharge tubes. We use these holes for our LEDs. Place a circle of the same diameter from a suitable piece of plastic cut out with nail scissors under the upper part. Thick cardboard will also work. It will fix the LED contacts.

   

   On the reverse side, the base has six round holes in which we will install the LEDs.

5. We have HK6 multichip LEDs (voltage 3.3V, wattage 0.33W, current 100-120mA). Each diode is assembled from six crystals (connected in parallel), so it shines brightly, although it is not called powerful. Considering the power of these LEDs, we connect them three in parallel.

   

   Each LED shines quite brightly on its own, so six in the lamp will provide good luminous intensity.

6. We connect both chains in series.

   

   Two chains of three parallel-connected LEDs, each connected in series

As a result, we get a pretty nice design.



Six LEDs inserted into the sockets create a powerful and uniform light source

7. A simple off-the-shelf driver can be taken from a broken LED lamp. Now, to connect six white 1-watt LEDs, we use such a 220-volt driver, for example, RLD2-1.

   

   Driver connects to LEDs in parallel

8. We insert the driver into the base. Another cut out circle of plastic or cardboard is placed between the board and the driver to avoid short circuits between the LED contacts and the driver parts. The lamp does not heat up, so any gasket is suitable.

   

   A positive difference between Chinese socles and Russian ones: they are soldered much better

9. We collect our lamp and check if it works.

   

   Having assembled the lamp, you need to connect it to a voltage source and make sure that it is on

We have created a light source with a luminous intensity of approximately 150-200 lumens and an output of approximately 3 watts, similar to a 30-watt incandescent lamp. But due to the fact that our lamp has a white glow color, it visually looks brighter. The area of ​​the room illuminated by it can be increased by bending the LED leads. In addition, we got a wonderful bonus: you don't even have to turn off a three-watt lamp - the meter practically does not "see" it.

Creating an LED lamp using a homemade driver

It is much more interesting not to use a ready-made driver, but to make it yourself. Of course, if you are good at a soldering iron and have basic reading skills for electrical circuits.

We'll cover etching the board after hand-drawing the circuit on it. And, of course, everyone will be interested in tinkering with chemical reactions using available chemicals. As in childhood.

We will need:

1. A piece of fiberglass foil on both sides with copper.
2. Elements of our future lamp according to the generated circuit: resistors, capacitor, LEDs.
3. Drill or mini drill for drilling fiberglass.
4. Pliers.
5. Soldering iron.
6. Solder and rosin.
7. Nail polish or clerical pencil.
8. Table salt, copper sulfate or ferric chloride solution.
9. Head on shoulders.
10. Skillful hands.
11. Neatness and attentiveness.

Textolite is used in cases where electrical insulating properties are needed. This is a multilayer plastic, the layers of which consist of fabric (depending on the type of fibers of the fabric layer, there are basalt-textolites, carbon-textolites, and others) and a binder (polyester resin, bakelite, etc.):

• fiberglass is a fiberglass impregnated with epoxy resin. It has a high resistivity and heat resistance - from 140 to 1800 o C;
• foil-clad fiberglass is a material covered with a layer of galvanic copper foil 35-50 microns thick. It is used to make printed circuit boards. Composite thickness - from 0.5 to 3 mm, sheet area - up to 1 m 2.

For the manufacture of printed circuit boards, foil-clad fiberglass is used

Driver circuit for LED lamp

A driver for an LED lamp can be made independently, for example, relying on the simplest circuit that we examined at the beginning of the article. There you just need to add a few details:

1. Resistor R3 to discharge the capacitor when the power is turned off.
2. A pair of zener diodes VD2 and VD3 to bypass the capacitor if the LED circuit burns out or breaks.

If we choose the right stabilization voltage, we can limit ourselves to one Zener diode. If we put a voltage higher than 220 V, and choose a capacitor for it, then we will do without additional details at all. But the driver will be larger in size, and the board may not fit in the base.

This circuit allows you to make a driver for a 20 LED lamp.

We created this circuit to make a 20 LED lamp. If there are more or less of them, you need to choose a different capacity of the capacitor C1 so that a current of 20 mA still flows through the LEDs.

The driver will lower the line voltage and try to smooth out power surges. Through a resistor and a current-limiting capacitor, the mains voltage is supplied to the bridge rectifier on diodes. Through another resistor, a constant voltage is applied to the LED block, and they begin to shine. The ripple of this rectified voltage is smoothed out by a capacitor, and when the lamp is disconnected from the network, the first capacitor is discharged by another resistor.

It will be more convenient if the driver structure is mounted using a printed circuit board, rather than a lump in the air of wires and parts. You can make the board yourself.

Step-by-step instructions for making an LED lamp with a homemade driver

1. Using a computer program, we generate our own pattern for etching the board according to the conceived driver design. The free Sprint Layout computer program is very convenient and popular among radio amateurs, which allows you to independently design printed circuit boards of low complexity and get an image of their wiring. There is another excellent domestic program - DipTrace, which draws not only boards, but also schematic diagrams.
   

   

   Sprint Layout, a freeware computer program, generates a detailed etching diagram for the driver board

2. We cut out a circle with a diameter of 3 cm from fiberglass. This will be our board.
3. Choosing a way to transfer the circuit to the board. All methods are terribly interesting. Can:
   • draw a diagram directly on a piece of fiberglass with a stationery correcting pencil or a special marker for printed circuit boards, which is sold in a radio parts store. There is a subtlety here: only this marker allows you to draw tracks less than or equal to 1 mm. In other cases, the width of the track, no matter how hard you try, will not be less than 2 mm. And the copper pads for soldering will come out sloppy. Therefore, after drawing the drawing, you need to correct it with a razor or scalpel;
   • print the diagram on an inkjet printer on photographic paper and steam the printout with an iron to fiberglass. The elements of the circuit will be covered with paint;
   • draw a diagram with nail polish, which is definitely in any house where a woman lives. This is the easiest way, and we will use it. Diligently and neatly draw the tracks on the board with a brush from the bottle. We are waiting for the varnish to dry well.
4. We dilute the solution: 1 tablespoon of copper sulfate and 2 tablespoons of table salt are stirred in boiling water. Copper sulfate is used in agriculture, so it can be bought at gardening and hardware stores.
5. We put the board in the solution for half an hour. As a result, only the copper tracks will remain, which we protected with varnish, the rest of the copper will disappear during the reaction.
6. Remove the remaining varnish from the fiberglass with acetone. Immediately, you need to tin (cover with solder with a soldering iron) the edges of the board and the contact points so that the copper does not rapidly oxidize.

   

   The contact points are soldered with a layer of solder mixed with rosin to protect the copper tracks from oxidation

7. According to the diagram, we make holes with a drill.
8. We solder the LEDs on the board and all the details of the homemade driver from the side of the printed tracks.
9. We install the board in the lamp body.

   

   After all the operations carried out, you should get an LED lamp equivalent to a 100-watt incandescent lamp.

Safety notes

1. Although assembling an LED lamp yourself is not a very difficult process, you should not even start it if you do not have at least some basic electrical knowledge. Otherwise, the lamp you assembled with an internal short circuit can harm the entire electrical network of your home, including expensive electrical appliances. The specificity of LED technology is that if some elements of its circuit are connected incorrectly, then even an explosion is possible. So you have to be extremely careful.
2. Luminaires are typically used at 220 VAC. But constructions designed for a voltage of 12 V cannot be connected to a regular network, and you should always remember this.
3. In the process of making a homemade LED lamp, the components of the luminaire often cannot be immediately completely isolated from the 220 V supply network. Therefore, you can be seriously electrocuted. Even if the structure is connected to the network via a power supply, it is quite possible that it has a simple circuit without a transformer and galvanic isolation. Therefore, the structure should not be touched with hands until the capacitors are discharged.
4. If the lamp does not work, then in most cases the poor-quality soldering of the parts is to blame. You were inattentive or hastily acted with a soldering iron. But don't be discouraged. Try further!

Video: learning to solder

It's a strange thing: in our age, when there is absolutely everything in stores, as a rule, inexpensive and very diverse, after twenty years of euphoria, people increasingly return to doing household things with their own hands. Handicrafts, carpentry and locksmith skills flourished unthinkably. And simple applied electrical engineering is confidently returning to this series.

The connection of high-power LEDs in lighting devices is carried out through electronic drivers that stabilize the current at their output.

Nowadays, the so-called energy-saving fluorescent lamps (compact fluorescent lamps - CFL) have become widespread. But over time they fail. One of the causes of the malfunction is a burnout of the lamp filament. Do not rush to dispose of such lamps because the electronic board contains many components that can be used later in other home-made devices. These are chokes, transistors, diodes, capacitors. Usually, these lamps have a working electronic board, which makes it possible to use it as a power supply or driver for an LED. As a result, in this way we will get a free driver for connecting LEDs, the more interesting it is.

You can watch the process of making homemade products in the video:

List of tools and materials
-energy-saving fluorescent lamp;
-screwdriver;
-soldering iron;
-tester;
- 10W white light-emitting diode;
-enamel wire with a diameter of 0.4 mm;
-thermopaste;
- diodes of the HER, FR, UF brands for 1-2A
-table lamp.

Step one. Disassembly of the lamp.
We disassemble the energy-saving fluorescent lamp by gently prying it off with a screwdriver. The bulb of the lamp must not be broken as there are mercury vapors inside. We call the filaments of the bulb with a tester. If at least one thread shows a break, then the bulb is faulty. If there is a working similar lamp, then you can connect the flask from it to the converted electronic board to make sure it is working properly.

Step two. Alteration of the electronic converter.
For the rework, I used a 20W lamp, the choke of which can withstand a load of up to 20W. For a 10W LED, this is sufficient. If you need to connect a more powerful load, you can use an electronic board for the lamp converter with the corresponding power, or change the choke with a larger core.

It is also possible to supply lower power LEDs by selecting the required voltage by the number of turns on the inductor.
I mounted the jumpers from the wire to the pins for connecting the lamp filaments.

Over the primary winding of the choke, you need to wind 20 turns of enamel wire. Then we solder the secondary wound winding to the rectifier diode bridge. We connect the voltage of 220V to the lamp and measure the voltage at the output from the rectifier. It was 9.7V. The LED connected through an ammeter draws a current of 0.83A. This LED has a rated current of 900mA, but in order to increase its resource in operation, the current consumption is specially underestimated. The diode bridge can be mounted on the board by surface mounting.

Diagram of the converted electronic board of the converter. As a result, we get a transformer from the choke with a connected rectifier. The added components are shown in green.

Step three. Assembling an LED table lamp.
We remove the socket for the 220 volt lamp. A 10W LED was installed on thermal paste on the metal shade of an old table lamp. The table lamp shade serves as a heat sink for the LED.

I placed the electronic power supply board and the diode bridge in the case of the table lamp stand.

Energy-saving lamps are widely used in everyday life and in production, over time they become unusable, and yet many of them can be restored after a simple repair. If the lamp itself is out of order, then a rather powerful power supply unit for any required voltage can be made from the electronic "filling".

What does a power supply from an energy-saving lamp look like?

In everyday life, a compact, but at the same time, powerful low-voltage power supply is often required; this can be done using a failed energy-saving lamp. In lamps, lamps most often fail, and the power supply remains in working order.

In order to make a power supply, it is necessary to understand the principle of operation of the electronics contained in the energy-saving lamp.

Advantages of switching power supplies

In recent years, there has been a clear tendency to move away from classical transformer power supplies to switching power supplies. This is due, first of all, to the great disadvantages of transformer power supplies, such as large mass, low overload capacity, low efficiency.

The elimination of these shortcomings in switching power supplies, as well as the development of the element base, made it possible to widely use these power nodes for devices with a power from a few watts to many kilowatts.

Power supply circuit

The principle of operation of a switching power supply in an energy-saving lamp is exactly the same as in any other device, for example, a computer or TV.

In general terms, the operation of a switching power supply can be described as follows:

• The alternating mains current is converted into direct current without changing its voltage, i.e. 220 V.
• A transistor pulse width converter converts DC voltage into rectangular pulses, with a frequency of 20 to 40 kHz (depending on the lamp model).
• This voltage is fed through the choke to the luminaire.

Consider the scheme and operation of the switching lamp power supply (figure below) in more detail.

Energy-saving lamp electronic ballast circuit

The mains voltage is fed to the bridge rectifier (VD1-VD4) through a limiting resistor R 0 of small resistance, then the rectified voltage is smoothed on a filtering high-voltage capacitor (C 0), and through a smoothing filter (L0) is fed to the transistor converter.

The start of the transistor converter occurs at the moment when the voltage across the capacitor C1 exceeds the opening threshold of the VD2 dinistor. This will start the generator on transistors VT1 and VT2, due to which self-generation occurs at a frequency of about 20 kHz.

Other circuit elements such as R2, C8 and C11 play a supporting role in making it easier to start the generator. Resistors R7 and R8 increase the closing speed of the transistors.

And resistors R5 and R6 serve as limiting resistors in the base circuits of transistors, R3 and R4 protect them from saturation, and in case of breakdown play the role of fuses.

Diodes VD7, VD6 are protective, although in many transistors designed for operation in such devices, such diodes are built-in.

TV1 is a transformer, from its windings TV1-1 and TV1-2, the feedback voltage from the generator output is supplied to the base circuits of the transistors, thereby creating conditions for the generator to operate.

In the figure above, the parts to be removed when reworking the block are highlighted in red, points А – А` must be connected with a jumper.

Alteration of the block

Before proceeding with the alteration of the power supply, you should decide on what current power you need to have at the output, the depth of modernization will depend on this. So, if a power of 20-30 W is required, then the alteration will be minimal and will not require much intervention in the existing circuit. If it is necessary to obtain a power of 50 or more watts, then a more thorough modernization will be required.

It should be borne in mind that the output of the power supply will be a constant voltage, not an alternating one. It is impossible to get an alternating voltage with a frequency of 50 Hz from such a power supply unit.

Determine the power

Power can be calculated using the formula:

Р - power, W;

I - current strength, A;

U - voltage, V.

For example, let's take a power supply with the following parameters: voltage - 12 V, current - 2 A, then the power will be:

Taking into account the overload, 24-26 W can be taken, so that for the manufacture of such a block, minimal intervention in the circuit of a 25 W energy-saving lamp is required.

New parts

Adding new parts to the diagram

The added details are highlighted in red, these are:

• diode bridge VD14-VD17;
• two capacitors C 9, C 10;
• additional winding placed on the ballast choke L5, the number of turns is selected empirically.

The added winding to the choke plays another important role of the isolation transformer, preventing the mains voltage from entering the power supply output.

To determine the required number of turns in the added winding, you should do the following:

1. a temporary winding is wound on the inductor, about 10 turns of any wire;
2. connected with a load resistance, with a power of at least 30 W and a resistance of about 5-6 ohms;
3. include in the network, measure the voltage across the load resistance;
4. the resulting value is divided by the number of turns, they find out how many volts are per 1 turn;
5. calculate the required number of turns for a constant winding.

A more detailed calculation is given below.

Test connection of the converted power supply

After that, it is easy to calculate the required number of turns. To do this, the voltage that is planned to be obtained from this unit is divided by the voltage of one turn, the number of turns is obtained, and about 5-10% is added to the result.

W = U out / U vit, where

W is the number of turns;

U out - the required output voltage of the power supply;

U vit - voltage per one turn.

Winding an additional winding on a standard choke

The original choke winding is under mains voltage! When winding an additional winding over it, it is necessary to provide interwinding insulation, especially if a PEL-type wire is wound, in enamel insulation. For interwinding insulation, polytetrafluoroethylene tape can be used to seal threaded connections, which is used by plumbers, its thickness is only 0.2 mm.

The power in such a unit is limited by the overall power of the used transformer and the permissible current of the transistors.

High power power supply unit

This will require a more complex upgrade:

• additional transformer on a ferrite ring;
• replacement of transistors;
• installation of transistors on radiators;
• an increase in the capacity of some capacitors.

As a result of such an upgrade, a power supply unit with a capacity of up to 100 W is obtained, with an output voltage of 12 V. It is capable of providing a current of 8-9 amperes. This is enough to power, for example, a medium power screwdriver.

The diagram of the upgraded power supply is shown in the figure below.

100W power supply

As you can see in the diagram, the resistor R 0 is replaced with a more powerful (3-watt) resistor, its resistance is reduced to 5 ohms. It can be replaced with two 2-watt 10 ohms by connecting them in parallel. Further, C 0 - its capacity is increased to 100 microfarads, with an operating voltage of 350 V. If it is undesirable to increase the dimensions of the power supply, then you can find a miniature capacitor of such a capacity, in particular, it can be taken from a camera-soap dish.

To ensure reliable operation of the unit, it is useful to slightly reduce the values ​​of the resistors R 5 and R 6, to 18–15 Ohm, and also to increase the power of the resistors R 7, R 8 and R 3, R 4. If the generation frequency turns out to be low, then the ratings of the capacitors C 3 and C 4 - 68n should be increased.

The most difficult thing can be making a transformer. For this purpose, in pulse units, ferrite rings of appropriate sizes and magnetic permeability are most often used.

Calculation of such transformers is rather complicated, but there are many programs on the Internet with which it is very easy to do, for example, "Lite-CalcIT Pulse Transformer Calculation Program".

What does a pulse transformer look like?

The calculation carried out using this program gave the following results:

A ferrite ring is used for the core, its outer diameter is 40, the inner diameter is 22, and the thickness is 20 mm. The primary winding with a PEL wire - 0.85 mm 2 has 63 turns, and two secondary windings with the same wire - 12.

The secondary winding must be wound in two wires at once, while it is advisable to first twist them slightly together along the entire length, since these transformers are very sensitive to the asymmetry of the windings. If this condition is not met, then the VD14 and VD15 diodes will heat up unevenly, and this will further increase the asymmetry, which, in the end, will disable them.

But such transformers easily forgive significant errors when calculating the number of turns, up to 30%.

Since this circuit was originally designed to work with a 20 W lamp, transistors 13003 are installed. In the figure below, position (1) is medium power transistors, they should be replaced with more powerful ones, for example, 13007, as in position (2). They may need to be installed on a metal plate (heat sink) with an area of ​​about 30 cm 2.

Trial

A test turn-on should be carried out with the observance of some precautions so as not to damage the power supply:

1. Make the first test switch-on through a 100 W incandescent lamp to limit the current to the power supply.
2. It is imperative to connect a 3-4 Ohm load resistor to the output, with a power of 50-60 W.
3. If everything went well, let it run for 5-10 minutes, turn off and check the degree of heating of the transformer, transistors and rectifier diodes.

If no mistakes were made during the replacement of parts, the power supply should work without problems.

If the test switch-on showed that the unit is working, it remains to test it in full load mode. To do this, reduce the resistance of the load resistor to 1.2-2 Ohm and connect it directly to the network without a light bulb for 1-2 minutes. Then turn off and check the temperature of the transistors: if it exceeds 60 0 C, then they will have to be installed on the radiators.