Schematic diagram of a 10 watt LED light bulb. Operating principle of LED lamps. Which LEDs are better

The task of reducing the amount of energy consumed is no longer just technical problem and moved into the area of ​​strategic direction of state policy. For the average consumer, this titanic struggle results in the fact that he is simply forcibly forced to switch from the familiar and simple-as-an-egg incandescent lamp to other light sources. For example, to LED lamps. For most people, the question of how an LED lamp works comes down only to the possibility of it practical application– Is it possible to screw it into a standard socket and connect it to a 220 volt household network. A short excursion into the principles of its operation and structure will help you make an informed choice.

Operating principle LED lamp based on much more complex physical processes than one that emits light through a red-hot metal thread. He is so interesting that it makes sense to get to know him better. It is based on the phenomenon of light emission that occurs at the point of contact of two dissimilar substances when passing through them electric current.

The most paradoxical thing about this is that the materials used to provoke the effect of light emission do not conduct electric current at all. One of them, for example, silicon is a ubiquitous substance and is constantly trampled under our feet. These materials will pass current, and only in one direction (that’s why they are called semiconductors), only if they are connected together. To do this, positively charged ions (holes) must predominate in one of them, and negative ones (electrons) in the other. Their presence or absence depends on the internal (atomic) structure of the substance and a non-specialist should not bother with the question of unraveling their nature.
The emergence of an electric current in a connection of substances with a predominance of holes or electrons is only half the battle. The process of transition from one to another is accompanied by the release of energy in the form of heat. But in the middle of the last century, mechanical compounds of substances were found in which the release of energy was also accompanied by a glow. In electronics, a device that allows current to flow in one direction is called a diode. Semiconductor devices made from materials that can emit light are called LEDs.

Initially, the effect of emitting photons from a semiconductor compound was possible only in a narrow part of the spectrum. They glowed red, green or yellow. The strength of this glow was extremely small. The LED was used only as an indicator lamp for a very long time. But now materials have been found whose combination emits light of much greater intensity and in a wide range, almost the entire visible spectrum. Almost, because a certain wavelength predominates in their glow. Therefore, there are lamps with a predominance of blue (cold) and yellow or red (warm) light.

Now that you understand in general terms the principle of operation of an LED lamp, you can move on to answering the question about the design of 220 V LED lamps.

Design of LED lamps

Externally, light sources that use the effect of photon emission when electric current passes through a semiconductor are almost no different from incandescent lamps. The main thing is that they have the usual metal base with a thread, which exactly replicates all standard sizes of incandescent lamps. This allows you to not change anything in the electrical equipment of the room to connect them.
However internal structure LED lamp 220 volts is very difficult. It consists of the following elements:

1) contact base;

2) a housing that simultaneously plays the role of a radiator;

3) power and control boards;

4) boards with LEDs;

5) transparent cap.

Power and control board

Understanding how 220-volt LED lamps work, first of all it is worth understanding that semiconductor elements cannot be powered by alternating current and voltage of this magnitude. Otherwise they will simply burn out. Therefore, in the body of this light source there is necessarily a board that reduces the voltage and rectifies the current.

The durability of the lamp largely depends on the design of this board. More precisely, what elements are at its input. The cheap ones have nothing except a resistor in front of the rectifying diode bridge. Miracles often happen (usually in lamps from the Middle Kingdom) when even this resistor is not present and the diode bridge is directly connected to the base. Such lamps shine very brightly, but their service life is extremely low if they are not connected through stabilizing devices. For this you can use, for example, ballast transformers.

The most common schemes are those in which a smoothing filter consisting of a resistor and a capacitor is created in the power supply circuit of the lamp control circuit. In the most expensive LED lamps, the power and control unit is built on microcircuits. They smooth out stress surges well, but their working life is not too high. Mainly due to the inability to establish effective cooling.

LED board

No matter how hard scientists try, inventing new substances with high radiation efficiency in the visible part of the spectrum, the principle of operation of an LED lamp remains the same, and each of its individual luminous elements is very weak. To achieve the desired effect, they are grouped in groups of several dozen and sometimes hundreds of pieces. For this, a dielectric board is used, on which metal conductive tracks are applied. It is very similar to those used in televisions, motherboards computers and other radio devices.
The LED board performs another important function. As you have already noticed, there is no step-down transformer in the control unit. Of course, it is possible to install it, but this will lead to an increase in the dimensions of the lamp and its cost. The problem of lowering the supply voltage to a nominal value that is safe for the LED is solved simply but extensively. All luminous elements are included in series, like in a Christmas tree garland. For example, if 10 LEDs are connected in series to a 220 volt circuit, then each will get 22 V (however, the current value will remain the same).
The disadvantage of this circuit is that a burnt-out element breaks the entire circuit and the lamp stops shining. In a non-working lamp, out of a dozen LEDs, only one or two may be faulty. There are craftsmen who resolder them and live in peace, but most inexperienced users throw the entire device in the trash.

By the way, recycling LED lamps is a separate headache, since they cannot be mixed with ordinary household waste.

Transparent cap

Basically, this element plays the role of protection against dust, moisture and playful hands. However, it also has a utilitarian function. Most LED lamp covers have a matte appearance. This solution might seem strange, since the power of the LED radiation is weakened. But its usefulness for specialists is obvious.

The cap is matte because it inside A layer of phosphor is applied - a substance that begins to glow under the influence of energy quanta. It would seem that here, as they say, oil is oil. But the phosphor has an emission spectrum several times wider than that of an LED. It is close to natural solar. If you leave the LEDs without such a “gasket”, then their glow will make your eyes get tired and hurt.

What are the benefits of such lamps

Now that you already know a lot about how an LED lamp works, it’s worth dwelling on its advantages. The main and indisputable thing is low energy consumption. A dozen LEDs produce radiation of the same intensity as a traditional incandescent lamp, but semiconductor devices consume several times less electricity. There is another advantage, but it is not so obvious. Lamps with this operating principle are more durable. True, provided that the supply voltage is as stable as possible.

It is impossible not to mention the disadvantages of such lamps. First of all, this concerns the spectrum of their radiation. It is significantly different from the sun - what the human eye has been accustomed to perceiving for thousands of years. Therefore, for your home, choose those lamps that shine yellow or reddish (warm) and have matte caps.

LED lamps are the most expensive lighting devices. But their quality and durability do not always correspond to the parameters indicated on the packaging. It’s a shame to throw away a lamp that has not served its intended life, having invested significant budgetary funds into it.

If you have a multimeter and soldering iron skills, then a faulty LED lamp can be repaired, saving money.

Design of LED lamps

The design of an LED lamp is slightly different from the design of a CFL. The figure shows the components that make up the lamp.

1. Diffuser. Designed for even distribution luminous flux in space and eliminating glare when looking at the LEDs.
2. LEDs.
3. LED base with printed conductors for their serial connection.
4. Cooling radiator. Necessary for removing heat generated during LED operation.
5. Driver. Generates the voltage required for LED operation.
6. Driver (lamp) housing.
7. Base.

Only the functional purpose needs explanation drivers. LED – semiconductor device, emitting light when current passes through it. Like a regular diode, it conducts in only one direction. When the polarity changes, the current through it is zero. Like a conventional diode, the voltage at the LED terminals does not exceed a few volts and does not change with increasing voltage.

Therefore, when serial connection LEDs, the voltage required for operation is calculated by multiplying the number of products by forward voltage drop current through them. It can be found in a reference book or measured. When connecting the required number of LEDs to a 220 V AC network, you need:

• reduce the voltage to the required value;
• convert from variable to constant;
• smooth out pulsations;
• protect the driver and its load from short circuits;
• protect the network from interference generated during device operation.

To reduce the voltage use:

• circuits with a capacitor;
• circuits with a step-down transformer;
• inverter circuits.

Circuits with a capacitor used in most LED lamp drivers for household use. They are simple and cheap, but this is their only advantage. Functionally, they are similar to a circuit with a quenching resistor connected in series with the load, through which the excess voltage “drops”. The use of a resistor is impractical, since it produces power comparable to or greater than that of the LEDs themselves.

The capacitor is on alternating current performs the same function - it also extinguishes voltage. Elements on the diagram C2, C3 And R1 designed to reduce the voltage to the required value.

The disadvantage of this scheme is the dependence of the load voltage on the supply voltage. The current through the LEDs is unstable and sometimes exceeds the permissible values. At this moment, the diodes may fail.

The second disadvantage is no galvanic isolation from the network. When repairing lamps do not touch live parts. Although the voltage on them is not dangerous, the “phase” of the supply network can come directly.

Transformer circuits used in high-power LED lamps, inverter- at large quantities LEDs or, if necessary, dimmable lamps.

For straightening AC voltage diode bridge is used VD1, and to smooth out pulsations - an electrolytic capacitor C4.

Resistors R2 And R3 necessary to limit the current when voltage is applied to the circuit. A discharged electrolytic capacitor has a low resistance and at the first moment of time the current through it is large. It can damage the semiconductor diodes of the rectifier. Additionally, these resistors act as fuses during short circuits. Resistor R4 discharges the capacitor after disconnecting from the network to ensure the lamp goes out as quickly as possible.

Details R2, R3 And R4 some manufacturers do not install. Capacitor C1 needed to prevent interference from lamp operation from entering the power supply.

Diagnostics and replacement of LEDs

Before starting repairs, remove the diffuser. Removal methods vary depending on the lamp design. Most of the diffusers can be removed with a screwdriver, for which you need to pry it in several places, finding a weak spot.

LEDs need to be inspected: black dots on some elements indicate their failure. The quality of soldering is also inspected - a broken contact in a series chain of LEDs interrupts their power supply. The same thing happens when any of the diodes fail.

The serviceability of the LEDs is checked with a multimeter. Their resistance in the forward direction is measured. It should be small; the value for comparison is determined on serviceable elements. When checking, functional diodes glow dimly. You can test the LEDs by applying voltage to them from a 9 V battery through a 1 kOhm resistor.

Detected faulty elements are desoldered from the board, and a jumper is soldered in place where they are installed. If there is a donor lamp, replace the LEDs, or use parts from LED strip with similar design and characteristics.

Solder the LEDs carefully. To do this, first heat the solder on one side and remove it using suction devices. If they are absent, after the solder has completely melted on one of the terminals, it is removed by vigorously shaking the board. Residues are removed with a clean tip (you can also shake it first) with a generous amount of rosin. The second pin is easier to unsolder.

After installing the jumper instead of the diode, the entire lamp will glow dimmer. This is due to the fact that the overall resistance of the circuit, although slightly, will decrease. The current through the lamp will increase, resulting in more voltage remaining across the capacitor. If one or three diodes are removed, this will not affect the operation of the lamp. But when there are few of them left, the increase in current will become so noticeable that the remaining parts will overheat, and the failure process will take on an avalanche-like character. Therefore, in case of widespread failure of LEDs, leave the lamp as a donor of parts, replacing it with a new one.

Driver repair

The weak point of drivers is current limiting resistors. They are checked first. You can replace burnt elements with the same or the closest resistance values.

Examination semiconductor diodes rectifier and capacitor performed with a multimeter in resistance testing mode. However there are more quick way check the serviceability of this section of the circuit. To do this, the voltage across the filter capacitor is measured. The expected value is calculated by multiplying the nameplate voltage on one diode by their number. If the measured voltage does not correspond to the required one or is zero, the search continues: the capacitor and diodes are checked. If the voltage is normal, look for an open circuit between the LEDs and the driver.

You can check diodes with a multimeter without removing them from the board. A short circuit in the diode or its break will be visible. When closed, the device will show zero in both directions; if there is a break, the resistance in the forward direction will not correspond to the resistance of the open p-n junction. You will recognize it on working elements. A short circuit in the diodes additionally leads to failure of the limiting resistor.

Repairing a transformer driver is a little more complicated than usual. But with the inverter you will have to tinker. There are more parts in it, and most importantly, it always includes a microcircuit. In order to draw a conclusion about its malfunction, you will need to either study in detail the principle of operation of the driver, or make sure that all the parts surrounding it are in good working order.

Despite the diversity on the country's shelves, they remain unrivaled due to their cost-effectiveness and durability. However, a quality product is not always purchased, because in a store you cannot take the product apart for inspection. And even in this case, it is not a fact that everyone will determine from what parts it is assembled. burn out, and buying new ones becomes expensive. The solution is to repair LED lamps yourself. Even a novice home craftsman can do this work, and the parts are inexpensive. Today we will figure out how to check in what cases the product is repaired and how to do it.

It is known that LEDs cannot operate directly from a 220 V network. To do this, they need additional equipment, which most often fails. We'll talk about it today. Let's consider the circuit, without which the operation of the lighting device is impossible. At the same time, we will conduct an educational program for those who do not understand anything about radio electronics.

The 220 V LED lamp driver circuit consists of:

• diode bridge;
• resistance;
• resistors.

The diode bridge serves to rectify the current (converts it from alternating to direct). On the graph it looks like cutting off a half-wave of a sine wave. Resistors limit the current, and capacitors store energy, increasing the frequency. Let's look at the operating principle of a 220 V LED lamp.

The principle of operation of the driver in an LED lamp

View on the diagram	Operating procedure
	A voltage of 220 V is supplied to the driver and passes through a smoothing capacitor and a current-limiting resistor. This is necessary in order to protect the diode bridge.
	Voltage is supplied to a diode bridge, consisting of four differently directed diodes, which cut off the half-wave of the sine wave. The output current is constant.
	Now, by means of a resistance and a capacitor, the current is again limited and the desired frequency is set.
	Voltage with the necessary parameters is supplied to unidirectional light diodes, which also serve as a current limiter. Those. when one of them burns out, the voltage increases, which leads to failure of the capacitor if it is not powerful enough. This happens in Chinese products. High-quality devices are protected from this.

Having understood the principle of operation and the driver circuit, the decision on how to repair a 220V LED lamp will no longer seem difficult. If we talk about quality products, then you shouldn’t expect any troubles from them. They work for the entire prescribed period and do not fade, although there are “diseases” to which they are also susceptible. Let's talk about how to deal with them now.

Reasons for failure of LED lighting devices

To make it easier to understand the reasons, let’s summarize all the data in one common table.

Good to know! Repair LED lamps impossible to carry out indefinitely. It is much easier to eliminate negative factors that affect durability and not purchase cheap products. Savings today will result in costs tomorrow. As economist Adam Smith said, “I am not rich enough to buy cheap things.”

Repairing a 220 V LED lamp with your own hands: nuances of the work

Before you repair an LED lamp with your own hands, pay attention to some details that require less labor. Checking the cartridge and the voltage in it is the first thing to do.

Important! Repairing LED lamps requires a multimeter - without it you will not be able to ring the driver elements. You will also need a soldering station.

A soldering station is necessary for repairing LED chandeliers and lamps. After all, overheating of their elements leads to failure. The heating temperature when soldering should be no higher than 2600, while the soldering iron heats up more. But there is a way out. We use a piece of copper wire with a cross-section of 4 mm, which is wound onto the soldering iron tip in a tight spiral. The more you lengthen the tip, the lower its temperature. It is convenient if the multimeter has a thermometer function. In this case, it can be adjusted more accurately.

But before you make any repairs LED spotlights, chandeliers or lamps, you need to determine the cause of failure.

How to disassemble an LED light bulb

One of the problems that a novice home DIYer faces is how to disassemble an LED light bulb. To do this you will need an awl, solvent and a syringe with a needle. The LED lamp diffuser is glued to the body with sealant, which needs to be removed. Carefully running an awl along the edge of the diffuser, inject the solvent with a syringe. After 2-3 minutes, easily twisting, the diffuser is removed.

Some lighting fixtures are made without sealant. In this case, it is enough to rotate the diffuser and remove it from the body.

Determining the cause of failure of an LED light bulb

After disassembling the lighting fixture, pay attention to the LED elements. Burnt is often identified visually: it has scorch marks or black dots. Then we replace the faulty part and check its functionality. We will tell you in detail about the replacement in step-by-step instructions.

If the LED elements are in order, move on to the driver. To check the functionality of its parts, you need to remove them from the printed circuit board. The value of resistors (resistances) is indicated on the board, and the parameters of the capacitor are indicated on the case. When testing with a multimeter in the appropriate modes, there should be no deviations. However, often failed capacitors are identified visually - they swell or burst. Solution - replacement with suitable technical parameters.

Replacing capacitors and resistances, unlike LEDs, is often done with a regular soldering iron. In this case, care should be taken not to overheat nearby contacts and elements.

Replacing light bulb LEDs: how difficult is it?

Subject to availability soldering station or a hairdryer, this job is simple. It is more difficult to work with a soldering iron, but it is also possible.

Good to know! If you don’t have working LED elements at hand, you can install a jumper instead of the burnt one. Such a lamp will not work for a long time, but it will be possible to gain some time. However, such repairs are carried out only if the number of elements is more than six. Otherwise, a day is the maximum work of the repair product.

Modern lamps operate on SMD LED elements, which can be desoldered from the LED strip. But it is worth choosing the ones that are suitable according to technical characteristics. If there are none, it is better to change everything.

Related article:

For the right choice You need to know not only general things about LED devices. Information about modern models, electrical diagrams of working devices. In this article you will find answers to these and other practical questions.

Repairing an LED lamp driver if you have an electrical diagram of the device

If the driver consists of SMD components that are smaller in size, we will use a soldering iron with copper wire on the sting. A visual inspection revealed a burnt element - unsolder it and select the appropriate one according to the markings. There are no visible damages - this is more difficult. You will have to solder all the parts and ring them separately. Having found a burnt one, we replace it with a functional one. It is convenient to use tweezers for this.

Useful advice! You should not remove all elements from the printed circuit board at the same time. They are similar in appearance, you can later confuse the location. It is better to unsolder the elements one by one and, after checking, mount them in place.

How to check and replace the power supply of LED lamps

When installing lighting in rooms with high humidity (or), stabilizing ones are used, which reduce the voltage to a safe one (12 or 24 volts). The stabilizer can fail for several reasons. The main ones are excessive load (power consumption of luminaires) or incorrect selection of the unit’s degree of protection. Such devices are repaired in specialized services. At home, this is unrealistic without equipment and knowledge in the field of radio electronics. In this case, the power supply will have to be replaced.

Very important! All work to replace the stabilizing LED power supply is carried out with the voltage removed. Don't rely on the switch - it may not be connected correctly. The voltage is turned off in the apartment's distribution panel. Remember that touching live parts with your hand is dangerous.

We need to pay attention to technical specifications devices - the power must exceed the parameters of the lamps that are powered from it. Having disconnected the failed unit, we connect a new one according to the diagram. She is in technical documentation device. This does not present any difficulties - all wires have color coding, and the contacts are a letter designation.

The degree of protection of the device (IP) also plays a role. For a bathroom, the device must be marked at least IP45.

Article

Before our eyes, a real revolution in lighting is taking place: the world is rapidly switching to LEDs. Just five years ago LED lamps were still around technical novelty, and now LED lighting used in all areas of life: led lights can be found even in villages, many offices, hotels and public buildings are illuminated with LED lamps, the vast majority of concert and theater lighting has become LED. Lamps of this type also appear in many apartments, because they can be bought even in grocery stores, and in household goods their range is wider than other types of lamps.

LED lamp is quite complicated electronic device with several dozen details on which the quality of light, its safety for health and the durability of the lamp depend.

⇡ Pros and cons

LED lamps have many advantages compared to conventional incandescent lamps:

• Economical - with the same amount of light, a modern LED lamp consumes 7-10 times less electricity.
• Durability - an LED lamp lasts 15-50 times longer than a conventional one.
• A little heating - the child will not get burned on the LED lamp in the table lamp.
• Same brightness at different voltages - unlike incandescent lamps, LED lamps shine just as brightly at undervoltage online.
• The ability to install an LED lamp, much brighter than an incandescent lamp, in a lamp that has a power limitation.
• Light good lamps visually indistinguishable from incandescent light.

There are also advantages when compared with compact fluorescent (energy-saving) lamps (CFL):

• Environmental friendliness - absence of hazardous substances (the bulb of any CFL contains mercury).
• Economical - the lamp consumes less energy with the same luminous flux.
• The LED lamp instantly lights up to full brightness, and the CFL smoothly increases brightness from 20% to 100% in a minute at room temperature and much more slowly at low temperatures.
• CFLs have a poor spectrum consisting of peaks of several colors. The spectrum of an LED lamp is much closer to natural light and incandescent light.

But, of course, there are also disadvantages:

• High price.
• Presence on the market of lamps with poor quality light (pulsation, bad color characteristics, uncomfortable color temperature, discrepancy between the luminous flux and the incandescent lamp equivalent declared).
• Some lamps have problems with switches that have an indicator.
• Only some expensive models support brightness adjustment (dimming).

Let's figure out the savings

The main advantage of LED lamps is energy savings. For the same amount of light emitted by the lamp, an LED lamp consumes 7-10 times less electricity than a conventional incandescent lamp. You can now buy 6-watt LED bulbs and 4-watt LED bulbs, which provide the same amount of light as a 60- and 40-watt incandescent bulb, respectively.

I calculated what the electricity costs would be when lighting a two-room apartment with conventional and LED lamps. Of course, this is an approximate calculation, but it allows you to get an idea of ​​the order of magnitude of possible savings.

The packaging of any incandescent lamp indicates a service life of 1,000 hours. If the lamps actually work for 1,000 hours (unfortunately, they often burn out much earlier), the lamps in the hallway and room will have to be changed twice a year, and in the kitchen and bedroom once. If a lamp costs 30 rubles, it will cost 690 rubles to buy new lamps. LED lamps do not have to be changed every six months, because their service life is 15-50 thousand hours. This is from 7 to 22 years when used 6 hours a day.

The purchase of lamps for this apartment will cost 4,045 rubles (7 E27 6 W lamps for 240 rubles, 11 “candles” 4 W for 215 rubles), and they will pay off in less than a year.

LED and energy saving lamps

LED bulbs are undoubtedly energy efficient, but the word "energy efficient" is attached to compact fluorescent lamps (CFLs), and CFLs and LED bulbs are very different things.

CFLs became widely available about ten years ago and were expected to replace incandescent lamps. However, CFLs turned out to be a dead-end branch of evolution. These lamps have many disadvantages: the lamp tube contains mercury, the lamp lights up slowly and does not shine at all in the cold, CFLs have a poor spectrum, consisting of peaks of several colors.

From July 1, 2016, in accordance with Decree of the Government of the Russian Federation No. 898 dated August 28, 2015, all state and municipal enterprises and institutions will be prohibited from purchasing any lamps containing mercury (including CFLs) through the public procurement system. Already, the number of CFLs in stores is constantly decreasing, and soon they will disappear completely.

Let's compare the light spectrum of an incandescent lamp, a fluorescent lamp and an LED lamp.

The spectrum of an LED lamp is much closer to natural light and incandescent light.

A little history

The glow of a semiconductor transition was first discovered in 1923 by the Soviet physicist Oleg Losev. The first LEDs were called "Losev Light" (Losev's light). First the red LED appeared, then yellow and green LEDs appeared in the early 70s. The blue LED was created in 1971 by Yakov Panchechnikov, but it was very expensive. In 1990, Japanese Suji Nakamura created a cheap and bright blue LED.

After the advent of the blue LED, it became possible to make white light sources with three crystals (RGB). Such sources are still used in concert and decorative lighting.

In 1996, the first white LEDs using a phosphor appeared. In them, blue or ultraviolet LED light is converted to white using a special chemical applied on top of light-emitting crystals.

Phosphor LED

In 2005, the efficiency of such LEDs reached 100 lm/W, which made it possible to begin using phosphor LEDs for lighting. Now the most efficient white LEDs already produce 200 lm/W, commercial lamps with standard sockets - up to 125 lm/W.

Types of LED lamps

LED lamps replicate all possible types of incandescent, halogen and fluorescent lamps. We produce regular lamps - "pears", "candles" and "balls" with E27 and E14 sockets, "mirror" lamps R39, R50 with E14 sockets, and R63 with E27 sockets, spots with GU10 and GU5.3 sockets, capsule microlamps with sockets G4 and G9, lamps for ceilings with socket GX53.

LED light sources are quickly gaining popularity and replacing uneconomical incandescent lamps and dangerous fluorescent analogues. They use energy efficiently, last a long time, and some of them can be repaired after failure.

To properly replace or repair a broken element, you will need an LED lamp circuit and knowledge of design features.

A close acquaintance with the design of an LED lamp may be required only in one case - if it is necessary to repair or improve the light source.

Home craftsmen, having a set of elements on hand, can independently assemble an LED lamp, but a beginner cannot do this. But, having studied the circuit and having basic skills in working with electronics, he can replace broken parts and restore the functionality of the device.

Considering that LED devices have become the basis of lighting systems for modern apartments, the ability to understand the structure of lamps and repair them can save a significant part of the family budget

Does it make sense to repair an LED lamp? Undoubtedly. Unlike analogues with incandescent filament for 10 rubles apiece, LED devices are expensive.

Let’s assume that a GAUSS “pear” costs about 80 rubles, and a better alternative OSRAM costs 120 rubles. Replacing a capacitor, resistor or diode will cost less, and the life of the lamp can be extended by timely replacement.

There are many modifications of LED lamps: candles, pears, balls, spotlights, capsules, strips, etc. They differ in shape, size and design. To clearly see the difference from an incandescent lamp, consider the common pear-shaped model.

Instead of a glass bulb there is a matte diffuser, the filament is replaced by “long-playing” diodes on the board, excess heat is removed by a radiator, and voltage stability is ensured by the driver

If you look away from the usual shape, you can notice only one familiar element - the base. The size range of socles remains the same, so they fit traditional sockets and do not require changing the electrical system.

But this is where the similarities end: the internal structure of LED devices is much more complex than that of incandescent lamps.

LED lamps are not designed to operate directly from a 220 V network, so a driver is located inside the device, which is both a power supply and control unit. It consists of many small elements, the main task of which is to rectify the current and reduce the voltage.

Circuits with capacitors to reduce voltage

To create the optimal voltage for operation of a device using diodes, the driver is assembled based on a circuit with a capacitor or a step-down transformer. The first option is cheaper, the second is used to equip high-power lamps.

There is a third type - inverter circuits, which are implemented either for the assembly of dimmable lamps, or for devices with a large number diodes.

Let's consider an example involving a capacitor, since such circuits are common in household lamps.

Elementary circuit of an LED lamp driver. The main elements that dampen the voltage are capacitors (C2, C3), but resistor R1 also performs the same function

Capacitor C1 protects against power line interference, and C4 smoothes out ripples. At the moment the current is supplied, two resistors - R2 and R3 - limit it and at the same time protect it from a short circuit, and the VD1 element converts alternating voltage.

When the current supply stops, the capacitor is discharged using resistor R4. By the way, R2, R3 and R4 are not used by all manufacturers of LED products.

Disadvantages of a circuit with capacitors:

1. The diodes may burn out, since the current supply is not stable. The load voltage is completely dependent on the supply voltage.
2. There is no galvanic isolation, so there is a risk of electric shock. It is not recommended to touch current-carrying elements when disassembling lamps, as they are under phase.
3. It is almost impossible to achieve high glow currents, because this will require an increase in capacitor capacities.

However, there are also many advantages, which is why capacitors remain popular. The advantages are ease of assembly, wide range of output voltages and low cost.

Feel free to experiment with self-production Moreover, some of the parts can be found in old receivers or televisions.

Sample Switching Driver - Model CPC9909

Unlike a linear driver with a capacitor, a pulsed one effectively protects LEDs from voltage surges and network interference.

Example pulse device The popular electronic model CPC9909 is used. The efficiency of its use reaches 98% - an indicator at which we can really talk about energy saving and savings.

The CPC9909 chip, developed by Clare, is often used for self-assembly LED lamps, including increased power. The controller is housed in a compact plastic housing

The device can be powered directly from high voltage– up to 550 V, since the driver is equipped with a built-in stabilizer. Thanks to the same stabilizer, the circuit has become simpler and the cost is lower.

LED driver circuit based on the CPC9909 chip. Advantages of the circuit: ability to operate in the temperature range from -55 °C to +85 °C and powered by alternating voltage current

The microcircuit is successfully used for the development of electrical networks for emergency and backup lighting, since it is suitable for boost converter circuits.

At home, lamps powered by batteries or drivers with a power not exceeding 25 V are most often assembled based on the CPC9909.

Types of dimmable drivers

Adjusting the brightness of lighting fixtures allows you to set the desired level of lighting in the room. This is convenient when creating separate zones, reducing the brightness of light during the day, or for highlighting interior items.

With the help of a dimmer, the use of electricity becomes more rational, and the service life of the electrical appliance increases.

Sample of a retro style lamp with a dimmer. In appearance, the tabletop lighting device resembles a kerosene lamp and has a brightness control knob on the side.

There are two types of dimmable drivers, each with their own advantages. The first ones work with PWM control.

They are installed between the lamp and the power supply. Energy is supplied in the form of pulses of different durations. An example of using a driver with PWM regulation is a creeping line.

Testing a 40W dimmable driver. It is designed for office lamps, as well as devices for car parks and public buildings where energy saving mode is required

Dimmable drivers of the second type act directly on the power source and are used for devices with stabilized current.

When regulating the current, a change in the shade of the glow may occur: diodes white when the current decreases, they begin to emit slightly yellow light, and when zoomed in – blue.

Brief review and testing of LED lamps

Although the principles of constructing driver circuits for various lighting devices are similar, there are differences between them both in the sequence of connecting the elements and in their choice.

Review of popular LED models

Let's look at the circuits of 4 lamps that are sold in the public domain. If desired, you can repair them yourself.

Image gallery

If you have experience working with controllers, you can replace the elements of the circuit, resolder it, and slightly improve it.

However, meticulous work and efforts to find elements are not always justified - it is easier to buy a new lighting fixture.

Option #1 – LED lamp BBK P653F

The BBK brand has two very similar modifications: the P653F lamp differs from the P654F model only in the design of the emitting unit. Accordingly, both the driver circuit and the design of the device as a whole in the second model are built according to the design principles of the first.

The driver circuit is standard, but complicated by the unusual location of the key and the embedded inductance. The fuse could be installed near the diode bridge, but it is missing

It's easy to spot flaws in the design. For example, the installation location of the controller: partly in the radiator, if there is no insulation, partly in the base. The assembly on the SM7525 chip produces an output of 49.3 V.

Option #2 – Ecola 7w LED lamp

The radiator is made of aluminum, the base is made of heat-resistant polymer gray. On printed circuit board Half a millimeter thick, there are 14 diodes connected in series.

Between the heatsink and the board there is a layer of heat-conducting paste. The base is fixed with self-tapping screws.

The controller circuit is simple, implemented on a compact board. The LEDs heat the base board to +55 ºС. There is practically no pulsation, radio interference is also excluded

The board is completely placed inside the base and connected with shortened wires. Emergence short circuits impossible, since there is plastic around - an insulating material. The result at the controller output is 81 V.

Option #3 – collapsible lamp Ecola 6w GU5.3

Thanks to the collapsible design, you can independently carry out repairs or improve the device driver.

However, the unsightly appearance and device design. An oversized radiator increases the weight, so additional fixation is recommended when attaching the lamp to the socket.

The board has compact dimensions and a well-thought-out arrangement of elements, for the fastening of which both planes are used. The presence of ripples is explained by the absence of a filter capacitor, which should be at the output

The disadvantage of the circuit is the presence of noticeable pulsations of the light flux and a high degree of radio interference, which will certainly affect the service life. The controller is based on a BP3122 microcircuit, the output value is 9.6 V.

Option #4 – Jazzway 7.5w GU10 lamp

The external elements of the lamp are easily detached, so you can get to the controller quickly enough by unscrewing two pairs of screws. Safety glass held on by latches. The board contains 17 diodes with serial communication.

However, the controller itself, located in the base, is generously filled with compound, and the wires are pressed into the terminals. To free them, you need to use a drill or use desoldering.

The disadvantage of the circuit is that the function of a current limiter is performed by a conventional capacitor. When the lamp is turned on, current surges occur, resulting in either burnout of the LEDs or failure of the LED bridge

There is no radio interference observed - and all thanks to the absence pulse controller, but at a frequency of 100 Hz, noticeable pulsations of light are observed, reaching up to 80% of the maximum value.

The result of the controller is 100 V output, but according to the general assessment, the lamp is more likely to be a weak device. Its cost is clearly overestimated and is equal to the cost of brands that are distinguished by stable product quality.

Conclusions and useful video on the topic

You can learn how drivers for LEDs are designed, what their features and functions are, from the videos below.

Analysis of the MR-16 LED lamp circuit:

Driver circuit for self-assembly of lamps with power up to 15W:

What the FT833A driver looks and does:

Homemade from scrap elements:

Nowadays you can purchase kits and individual elements for assembling lighting fixtures of various power. If desired, you can repair a failed LED lamp or modify a new one to obtain best result. When purchasing, we recommend that you carefully check the characteristics and suitability of the parts.