Modern fluorescent bulbs are a real find for thrifty consumers. They shine brightly, work longer than incandescent bulbs and consume much less energy. At first glance - some advantages. However, due to the imperfection of domestic power grids, they exhaust their resources much earlier than the deadlines announced by manufacturers. And often they don’t even have time to “cover” the costs of their acquisition.
But do not rush to throw out the failed "housekeeper". Given the considerable initial cost of fluorescent bulbs, it is advisable to “squeeze” the maximum out of them, using to the last all their possible resources. Indeed, right under the spiral, a compact high-frequency converter circuit is installed in it. For a person who knows - this is a whole "Klondike" of all kinds of spare parts.
Disassembled lamp
General information
Battery
In fact, such a circuit is almost a ready-made switching power supply. It lacks only an isolation transformer with a rectifier. Therefore, if the flask is intact, you can try to disassemble the case without fear of mercury vapor.
By the way, it is the lighting elements of bulbs that most often fail: due to burnout of the resource, merciless operation, too low (or high) temperatures, etc. Internal boards are more or less protected by a sealed case and parts with a margin of safety.
We advise you to save up a certain number of lamps before starting repair work (you can ask around at work or with friends - usually this kind of stuff is enough everywhere). It is not a fact that they will all be maintainable. In this case, it is the efficiency of the ballast that is important to us (i.e., the board integrated inside the bulb).
Perhaps for the first time you will have to dig a bit, but then in an hour you will be able to assemble a primitive power supply for devices that are suitable in capacity.
If you plan to create a power supply, choose models of fluorescent lamps more powerful, starting from 20 watts. However, less bright bulbs will also be used - they can be used as donors of the necessary parts.
And as a result, from a couple of burned housekeepers it is quite possible to create one completely capable model, whether it be a work light, a power supply or a battery charger.
Most often, self-taught masters use the ballast of housekeepers to create 12-watt power supplies. They can be connected to modern LED systems, because 12 V is the operating voltage of most of the most common household appliances, including lighting.
Such blocks are usually hidden in furniture, so the appearance of the unit does not really matter. And even if outwardly the craft turns out to be sloppy - it's okay, the main thing is to take care of maximum electrical safety. To do this, carefully check the created system for operability, leaving it to work in test mode for a long time. If power surges and overheating are not observed, it means that you did everything right.
It is clear that you will not extend the life of the updated bulb much - anyway, sooner or later the resource will be exhausted (the phosphor and the filament will burn out). But you must agree, why not try to restore a failed lamp within six months or a year after purchase.
Disassemble the lamp
So, we take a non-working light bulb, we find the junction of a glass bulb with a plastic case. Gently pry the halves with a screwdriver, gradually moving along the "girdle". Usually these two elements are connected by plastic latches, and if you intend to use both components in any other way, do not apply much effort - a piece of plastic can easily crack, and the tightness of the bulb housing will be impaired.
After opening the case, carefully disconnect the contacts coming from the ballast to the filaments in the bulb, as they block full access to the board. Often they are simply tied to the pins, and if you do not plan to use the failed flask anymore, you can safely cut off the connecting wires. As a result, you should see something like this pattern.
Lamp disassembly
It is clear that the design of lamps from different manufacturers may differ in "filling." But the general scheme and the basic constituent elements have much in common.
Then you need to carefully examine every detail for blisters, breakdowns, make sure that all the elements are soldered reliably. If any of the parts burned out, it will be immediately visible by the characteristic soot on the board. In cases where no visible defects were found, but the lamp is not working, use the tester and “ring” all the elements of the circuit.
As practice shows, most often resistors, capacitors, dinistors suffer from large voltage drops that occur with unenviable regularity in domestic networks. In addition, frequent clicking of the switch has an extremely negative effect on the duration of the fluorescent bulbs.
Therefore, in order to extend their operating time for as long as possible, try to turn them on and off as little as possible. Saved on pennies in the end will result in hundreds of rubles for the replacement of a burned out bulb ahead of time .
Disassembled lamps
If, as a result of the initial inspection, you identify tan marks on the board, swelling of the parts, try replacing the failed blocks by taking them from other non-working donor bulbs. After installing the parts again, “ring” the tester all the components of the board.
By and large, a pulsed power supply unit with a power corresponding to the original lamp power can be made from the ballast of an inoperative fluorescent light bulb. As a rule, low-power power supplies do not require significant modifications. But over blocks of greater power, of course, have to sweat.
To do this, it will be necessary to slightly expand the capabilities of the native inductor, providing it with an additional winding. You can adjust the power of the created power supply by increasing the number of secondary turns on the inductor. Want to know how to do this?
Preparatory work
As an example, below is a diagram of a Vitoone fluorescent bulb, but in principle the composition of the boards from different manufacturers does not differ much. In this case, a bulb of sufficient power is presented - 25 watts, it can make an excellent 12 V charging unit.
Vitoone 25W lamp circuit
Power supply assembly
Red color on the diagram indicates the lighting unit (i.e. bulb with filament). If the threads in it burn out, then this part of the light bulb will no longer be needed, and you can safely bite off the contacts from the board. If the light bulb still burned before the breakdown, albeit dimly, you can then try to reanimate it for some time by connecting it to a working circuit from another product.
But this is not about that. Our goal is to create a power supply with ballast extracted from a light bulb. So, we delete everything that is between points A and A´ in the above diagram.
For a small power supply unit (approximately equal to the initial one for a donor bulb), only a small alteration is enough. A jumper must be installed in place of the remote lamp unit. To do this, simply rewind a new piece of wire to the released pins - at the place of attachment of the former filaments of the energy-saving light bulb (or to the holes for them).
In principle, you can try to slightly increase the generated power by supplying an additional (secondary) winding to the inductor already on the board (it is indicated on the diagram as L5). Thus, his native (factory) winding becomes primary, and another layer of the secondary one provides the same reserve of power. And again, it can be adjusted by the number of turns or the thickness of the wire being wound.
Power supply connection
But, of course, it will not be possible to significantly increase the initial capacities. Everything rests on the size of the "frame" around ferrites - they are very limited, because originally intended for use in compact lamps. Often it is possible to apply turns in only one layer, eight to ten will be enough for a start.
Try to apply them evenly over the entire ferrite area to get maximum performance. Such systems are very sensitive to the quality of the winding and will heat up unevenly, and in the end will become worthless.
We recommend that you remove the throttle from the circuit for the duration of the work, since otherwise it will not be easy to win. Clean it from factory glue (resins, films, etc.). Visually assess the condition of the primary winding wire, check the integrity of the ferrite. Since if they are damaged, it makes no sense to continue to work with him in the future.
Before starting the secondary winding, lay a strip of paper or electric cardboard on top of the primary winding to avoid the possibility of breakdown. Adhesive tape in this case is not the best option, since over time the adhesive composition appears on the wires and leads to corrosion.
The circuit of the modified board from the light bulb will look like this
Scheme of a modified board from a light bulb
Many people know firsthand that doing the transformer winding with their own hands is still a pleasure. This is more of an exercise for the diligent. Depending on the number of layers, you can spend from a couple of hours to the whole evening.
Due to the limited space of the throttle window, to create a secondary winding, we recommend using a varnished copper cable with a cross section of 0.5 mm. Because the wires in isolation there simply does not have enough space for winding any significant number of turns.
If you decide to remove the insulation from your existing wire, do not use a sharp knife, as after violating the integrity of the outer layer of the winding, one can only hope for the reliability of such a system.
Cardinal transformations
Ideally, for the secondary winding, you need to take the same type of wire as in the original factory version. But often the “window” of the throttle magnet receiver is so narrow that it is not even possible to wind one full layer. And yet, it is necessary to take into account the thickness of the strip between the primary and secondary windings.
As a result, it is impossible to radically change the power output by the lamp circuit without making changes to the composition of the board components. In addition, no matter how carefully you do the winding, you will not succeed in making it as qualitatively as in models produced by the factory method. And in this case, it’s easier then to assemble the impulse block from scratch than to remake the “good”, obtained free of charge from a light bulb.
Therefore, it is more rational to search for a ready-made transformer with the desired parameters on the showdowns of the old computer or television and radio equipment. It looks much more compact than "homemade". And its margin of safety does not go to any comparison.
Transformer
And you do not have to puzzle over the calculations of the number of turns to obtain the desired power. Soldered to the circuit - and you're done!
Therefore, if the power of the power supply needs more, say about 100 W, then you have to act radically. And only the spare parts available in the lamps can not do here. So if you want to further increase the power of the power supply, you need to drop out and remove the native inductor from the light bulb board (indicated in the diagram below as L5).
UPS detail diagram
Connected transformer
Then, in the section between the former location of the throttle and the reactive midpoint (in the diagram, this segment is located between the isolation capacitors C4 and C6), a new powerful transformer (designated as TV2) is connected. If necessary, an output rectifier is connected to it, consisting of a pair of connecting diodes (they are indicated on the diagram as VD14 and VD15). It does not hurt to simultaneously replace with more powerful diodes on the input rectifier (in the diagram it is VD1-VD4).
Do not forget to install a more capacious capacitor (shown in the diagram as C0). You need to select it from the calculation of 1 microfarad per 1 W of output power. In our case, a capacitor of 100 mF was taken.
As a result, we get a fully capable switching power supply from an energy-saving lamp. The assembled circuit will look something like this.
Test run
Test run
Connected to a circuit, it serves as something akin to the stabilizer fuse and protects the unit in case of current and voltage drops. If all is well, the lamp does not particularly affect the operation of the board (due to low resistance).
But at high current surges, the lamp resistance increases, leveling the negative impact on the electronic components of the circuit. And even if the lamp suddenly burns out - it will not be so miserable as a pulsed block with your own hand assembled over which you pored for several hours.
The simplest test circuit diagram looks like this.
After starting the system, observe how the temperature of the transformer (or the choke wrapped in the secondary circuit changes). In the event that it begins to heat up strongly (up to 60 ° C), disconnect the circuit and try replacing the winding wires with an analog with a large cross section, or increase the number of turns. The same goes for the heating temperature of transistors. With its significant growth (up to 80ºС), each of them should be equipped with a special radiator.
That's basically it. Finally, we remind you of compliance with safety rules, since the output voltage is very high. In addition, the components of the board can become very hot, without changing at the same time externally.
Also, we do not recommend using such impulse blocks when creating chargers for modern gadgets with thin electronics (smartphones, electronic watches, tablets, etc.). Why take this risk? No one will guarantee that the "homemade" will work stably, and will not ruin an expensive device. Moreover, there is more than enough suitable goods (meaning ready-made charges) on the market, and they are quite inexpensive.
Such a home-made power supply can be safely used to connect different types of bulbs, to power LED strips, simple electrical appliances that are not so sensitive to current surges (voltage).
We hope you were able to master all the material given. Perhaps it will inspire you to try to create something like this yourself. Even if the first power supply unit you made from the light bulb board at first will not be a real working system, you will gain basic skills. And most importantly - excitement and thirst for creativity! And there, you look, and it will turn out to be made from improvised materials a full-fledged power supply for LED strips, very popular today. Good luck
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Supplement:
The power of the power supply is limited by the overall power of the pulse transformer, the maximum allowable current of the key transistors and the size of the cooling radiator, when used.
A small power supply can be built by winding the secondary winding directly onto the frame of an existing inductor from the lamp unit.
If the throttle window does not allow the secondary winding to be wound, or if you want to build a power supply unit with a power significantly exceeding the CFL power, then an additional pulse transformer will be needed. 
If you want to get a power supply with a capacity of more than 100 watts, and using ballast from a lamp of 20-30 watts, then most likely you will have to make small changes to the electronic ballast circuit.
In particular, it may be necessary to install more powerful VD1-VD4 diodes in the input bridge rectifier and rewind the input inductor L0 with a thicker wire. If the current transistor gain is insufficient, then the base current of the transistors will have to be increased by reducing the values \u200b\u200bof the resistors R5, R6. In addition, it is necessary to increase the power of resistors in the base and emitter circuits.
If the generation frequency is not very high, then it may be necessary to increase the capacitance of the separation capacitors C4, C6.
R0 - limits the peak current flowing through the rectifier diodes at the time of switching on. In CFL, it also often serves as a fuse.
VD1 ... VD4 - bridge rectifier.
L0, C0 - power filter.
R1, C1, VD2, VD8 - converter start-up circuit.
The startup node works as follows. Capacitor C1 is charged from the source through resistor R1. When the voltage across capacitor C1 reaches the breakdown voltage of the dynistor VD2, the dynistor unlocks itself and unlocks the transistor VT2, causing self-oscillations. After generation, rectangular pulses are applied to the cathode of the VD8 diode and the negative potential is reliably blocked by the VD2 dynistor.
R2, C11, C8 - make it easy to start the converter.
R7, R8 - improve the locking of transistors.
R5, R6 - limit the current base of transistors.
R3, R4 - prevent the saturation of transistors and act as fuses for breakdown of transistors.
VD7, VD6 - protect transistors from reverse voltage.
TV1 is a feedback transformer.
L5 - ballast throttle.
C4, C6 - isolation capacitors, on which the supply voltage is divided in half.
TV2 is a pulse transformer.
VD14, VD15 - pulse diodes.
C9, C10 - filter capacitors.
While scientists are taming the speed of light, I decided to tame unnecessary fluorescent lamps, converting them into LED. Compact fluorescent lamps (CFLs) are a bit of a thing of the past, for obvious reasons: lower efficiency relative to LEDs, environmental insecurity (mercury), ultraviolet radiation, which is dangerous for human eyes, and also fragility.
Like many hams, a whole box of this "good" has accumulated. Less powerful can be used as spare parts, but those that are more powerful, starting from 20W, you can redo power supplies. Indeed, electronic ballast is a cheap voltage converter, that is, a simple and affordable switching power supply which can be used to power devices up to 30-40W (depends on CFL), and even more if you change the output choke and transistors. Those radio amateurs who live in remote places, or in certain situations, these "energy savers" will be useful. So, do not rush to throw them out after failure - and they do not work for long!
In my case, about a year ago (in the spring of 2014), having started experimenting with electronic ballast, in search of a housing for an alteration into an LED lamp, returning home from work in the evening, it dawned on me - seeing a can of cola on the sidewalk. After all, the aluminum case from under the 0.25L drink is just suitable as a radiator for heat dissipation of an LED strip. And also, it ideally sits under the CFO “Vitoone” case with the E27 base, at 25 W. Yes, and in aesthetics it’s not bad!
Having made several redesigned LED lamps, I began to test them in different operating conditions. One of them works in the utility room in the heat and frost (with ventilation holes), the other in the living room (without a hole in the plastic base). Another is connected to a three-meter LED strip. Almost a year has passed, and they still serve without fail! Well, and considering that on the topic of LEDs, the article appears more and more, I had to finally write about my time-tested ideas.
Discuss article LAMP LED UNIVERSAL
Chinese screwdrivers are notable for their low price and bad batteries, which become unusable after the first year of operation. Buying a new battery does not make sense, so the question arises of mains power. This power supply consists of accessible parts and fits completely in the battery case.
It is based on a board from an energy-saving lamp, a pulse transformer and an output choke from a computer power supply. I had two identical boards from 95 W lamps, but both turned out to have burned field effect transistors, so I had to change them. The lamp circuit is shown in the figure:
Parts marked in red must be removed. From the output choke from the computer power supply unit L3 (see diagram below) we remove all windings except the one that is wound with the thickest wire. We solder new parts according to the scheme:
The input chain of the fuse and thermistor can not be set. Capacitor C1 set the maximum capacity. If your energy-saving lamp is made on bipolar transistors (most often 13003, 13005), then they must be replaced with more powerful ones (13007, 13009). It may also be necessary to replace the diode bridge D1-D4 and the inductance L1. To avoid these alterations, it is necessary to take a board from the lamp as much as possible.
The Schottky output diodes D12, D13 (10A 100V) were taken with a margin, since during the tests the diodes from the mospec s20c40c computer power supply failed. The EL car lamp is used as a backlight, a power and load indicator. Field-effect transistors and schottky diodes are equipped with radiators.
The work of the screwdriver is presented in the video:
Despite the small size of the energy-saving lamps, they have a lot of electronic components. In its structure, it is an ordinary tubular fluorescent lamp with a miniature bulb, but only coiled into a spiral or other spatial compact line. It is therefore called a compact fluorescent lamp (in abbreviation CFL).
And it is characterized by all the same problems and malfunctions as with large tubular bulbs. But the electronic ballast of the light bulb, which has ceased to shine, most likely due to a burnt out spiral, usually maintains its efficiency. Therefore, it can be used for any purpose as a switching power supply (in the reduction of UPS), but with preliminary refinement. This will be discussed further. Our readers will learn how to make a power supply from an energy-saving lamp.
What is the difference between UPS and electronic ballast
Let us immediately warn those who expect to receive a powerful power source from CFL - it is impossible to get more power as a result of a simple ballast alteration. The fact is that in inductance coils that contain cores, the working magnetization zone is strictly limited by the design and properties of the magnetizing voltage. Therefore, the pulses of this voltage created by the transistors are precisely selected and determined by the circuit elements. But such a power supply from electronic ballasts is quite sufficient to power the LED strip. Moreover, a switching power supply from an energy-saving lamp corresponds to its power. And it can be up to 100 watts.
The most common CFL ballast scheme is built according to the half-bridge (inverter) scheme. This is a TV transformer based oscillator. The winding TV1-3 magnetizes the core and performs the function of a choke to limit the current through the EL3 lamp. The windings TV1-1 and TV1-2 provide positive feedback for the appearance of voltage controlling transistors VT1 and VT2. The diagram shows in red the CFL bulb with elements that ensure its launch.
An example of a common CFL ballast pattern
All inductors and capacitances in the circuit are selected so as to obtain precisely dosed power in the lamp. The efficiency of transistors is associated with its value. And since they do not have radiators, it is not recommended to strive to receive significant power from the converted ballast. The ballast transformer does not have a secondary winding from which the load is supplied. This is the main difference between it and the UPS.
What is the essence of ballast reconstruction
To be able to connect the load to a separate winding, you must either rewind it on the L5 inductor or use an additional transformer. Alteration of ballast in the UPS includes:
For further conversion of electronic ballast into a power supply from an energy-saving lamp, a decision must be made regarding the transformer:
- use the existing throttle, modifying it;
- either apply a new transformer.
Choke transformer
Next, consider both options. In order to use an electronic ballast inductor, it must be removed from the board and then disassembled. If an U-shaped core is used in it, it contains two identical parts that are interconnected. In this example, an orange tape is used for this purpose. She carefully removed.
Removing the tape tightening the halves of the core
The halves of the core are usually glued so that there is a gap between them. It serves to optimize the magnetization of the core, slowing down this process and limiting the slew rate of the current. We take our pulse soldering iron and heat the core. We apply it to the soldering iron in places where the halves are connected.
Having disassembled the core, we get access to the coil with a wound wire. Winding, which is already on the reel, is not recommended for unwinding. From this, the magnetization mode will change. If the free space between the core and the coil allows you to wrap one layer of fiberglass to improve the insulation of the windings from each other, you need to do this. And then wrap ten turns of the secondary winding with a wire of suitable thickness. Since the power of our power supply will be small, a thick wire is not needed. The main thing is that it fits on a reel, and the halves of the core are allotted to it.
After winding the secondary winding, we collect the core and fasten the halves with duct tape. We assume that after testing the PSU it will become clear what voltage is generated in one turn. After testing, we will analyze the transformer and add the required number of turns. Typically, the alteration is intended to make a voltage converter with an output of 12 V. This allows using a stabilization charger for the battery. The same voltage can be made from an energy-saving lamp, as well as charge a flashlight powered by a battery.
Since the transformer of our UPS, most likely, will have to be jacked, it is not worth soldering it into the board. It is better to solder the wires sticking out of the board, and solder the conclusions of our transformer to them for the duration of the test. The ends of the terminals of the secondary winding must be cleaned of insulation and coated with solder. Then, either on a separate socket or directly on the terminals of the wound winding, it is necessary to assemble a rectifier on high-frequency diodes according to the bridge circuit. A capacitor of 1 μF 50 V is sufficient for filtering during voltage measurement.
UPS testing
But before connecting to a 220 V network, a powerful resistor is surely connected to our block, remade with our own hands from a lamp. This is a safety measure. If a short-circuit current flows through the pulse transistors in the power supply, the resistor will limit it. In this case, an incandescent bulb of 220 V can become a very convenient resistor. In terms of power, it is enough to use a 40-100-watt lamp. When a short circuit occurs in our device, the light will glow.
Next, we connect the multimeter probes to the rectifier in the constant voltage measurement mode and apply 220 V to the electric circuit with a light bulb and a power supply board. Twists and open live parts must be isolated beforehand. To supply voltage, it is recommended to use a wired switch, and put a light bulb in a liter jar. Sometimes, when turned on, they burst, and the fragments fly apart. Usually tests pass without problems.
More powerful UPS with separate transformer
They allow you to determine the voltage and the required number of turns. The transformer is being finalized, the unit is tested again, and after that it can be used as a compact power source, which is much smaller than the analogue based on a conventional 220 V transformer with a steel core.
To increase the power of the power supply, it is necessary to use a separate transformer, made similarly from a choke. It can be removed from a bulb of higher power, which burned completely together with semiconductor products of ballast. The same circuit is taken as the basis, which is distinguished by the addition of an additional transformer and some other parts shown in red lines.
The rectifier shown in the image contains fewer diodes compared to the rectifier bridge. But for its work, more turns of the secondary winding will be required. If they do not fit into the transformer, a rectifier bridge must be used. A more powerful transformer is made, for example, for halogens. Anyone who used a conventional transformer for a halogen lighting system knows that they are powered by a fairly large current. Therefore, the transformer is bulky.
If the transistors are placed on radiators, the power of one power supply can be significantly increased. And in terms of weight and dimensions, even several such UPSs for working with halogen lamps will be smaller and lighter than one transformer with a steel core of equal power to them. Another option for the use of workable housekeeping ballasts may be their reconstruction for an LED lamp. Converting an energy-saving lamp into an LED design is very simple. The lamp is disconnected, and a diode bridge is connected instead.
At the output of the bridge, a certain number of LEDs are connected. They can be connected to each other in series. It is important that the LED current is equal to the current in CFL. can be called a valuable mineral in the era of LED lighting. They can find application even after the end of their service life. And now the reader knows the details of this application.