LED lamp circuit: device of the simplest drivers. Save on replacement: do-it-yourself repair of LED lamps Design of a 220 LED lamp

Because you need to competently solve two problems at once:

1. Limit the forward current through the LED to prevent it from burning out.
2. Protect the LED from breakdown by reverse current.

If you ignore any of these points, the LED will instantly be covered with a copper basin.

In the simplest case, you can limit the current through the LED with a resistor and/or capacitor. And you can prevent breakdown from reverse voltage using a conventional diode or another LED.

Therefore, the simplest circuit for connecting an LED to 220V consists of only a few elements:

The protective diode can be almost anything, because its reverse voltage will never exceed the forward voltage across the LED, and the current is limited by a resistor.

The resistance and power of the limiting (ballast) resistor depends on the operating current of the LED and is calculated according to Ohm’s law:

R = (U in - U LED) / I

And the power dissipation of the resistor is calculated as follows:

P = (U in - U LED) 2 / R

where Uin = 220 V,
U LED - forward (operating) voltage of the LED. Usually it lies in the range of 1.5-3.5 V. For one or two LEDs it can be neglected and, accordingly, simplify the formula to R = U in / I,
I - LED current. For conventional indicator LEDs, the current will be 5-20 mA.

Example of calculating a ballast resistor

Let's say we need to get the average current through the LED = 20 mA, therefore the resistor should be:

R = 220V/0.020A = 11000 Ohm(take two resistors: 10 + 1 kOhm)

P = (220V) 2 /11000 = 4.4 W(take with reserve: 5 W)

The required resistor value can be taken from the table below.

Table 1. Dependence of LED current on the resistance of the ballast resistor.

Resistor resistance, kOhm	Amplitude value of current through the LED, mA	Average LED current, mA	Average resistor current, mA	Resistor power, W
43	7.2	2.5	5	1.1
24	13	4.5	9	2
22	14	5	10	2.2
12	26	9	18	4
10	31	11	22	4.8
7.5	41	15	29	6.5
4.3	72	25	51	11.3
2.2	141	50	100	22

Other connection options

In previous circuits, the protective diode was connected back-to-back, but it can be placed like this:

This is the second circuit for switching on 220 volt LEDs without a driver. In this circuit, the current through the resistor will be 2 times less than in the first option. And, therefore, it will release 4 times less power. This is a definite plus.

But there is also a minus: the full (amplitude) mains voltage is applied to the protective diode, so any diode will not work here. You'll have to find something with a reverse voltage of 400 V or higher. But these days this is not a problem at all. The ubiquitous 1000 volt diode, 1N4007 (KD258), is perfect, for example.

Despite the common misconception, during negative half-cycles of the mains voltage, the LED will still be in a state of electrical breakdown. But due to the fact that the resistance of the reverse-biased p-n junction of the protective diode is very high, the breakdown current will not be sufficient to damage the LED.

Attention! All the simplest circuits for connecting 220 volt LEDs have a direct galvanic connection to the network, so touching ANY point of the circuit is EXTREMELY DANGEROUS!

To reduce the value of the touch current, you need to halve the resistor into two parts so that it turns out as shown in the pictures:

Thanks to this solution, even if the phase and zero are reversed, the current through a person to the “ground” (if accidentally touched) cannot exceed 220/12000 = 0.018A. And this is no longer so dangerous.

What about pulsations?

In both schemes, the LED will light only during the positive half-cycle of the mains voltage. That is, it will flicker at a frequency of 50 Hz or 50 times per second, and the pulsation range will be equal to 100% (10 ms on, 10 ms off, and so on). It will be noticeable to the eye.

In addition, when flickering LEDs illuminate any moving objects, for example, fan blades, bicycle wheels, etc., a stroboscopic effect will inevitably occur. In some cases, this effect may be unacceptable or even dangerous. For example, when working at a machine, it may seem that the cutter is motionless, but in fact it is rotating at breakneck speed and is just waiting for you to stick your fingers into it.

To make the ripple less noticeable, you can double the LED switching frequency using a full-wave rectifier (diode bridge):

Please note that compared to circuit #2 with the same resistor value, we got twice the average current. And, accordingly, four times the power dissipation of the resistors.

There are no special requirements for the diode bridge, the main thing is that the diodes that make it up can withstand half the operating current of the LED. The reverse voltage on each of the diodes will be completely negligible.

Another option is to organize back-to-back switching of two LEDs. Then one of them will burn during the positive half-wave, and the second - during the negative half-wave.

The trick is that with this connection, the maximum reverse voltage on each of the LEDs will be equal to the forward voltage of the other LED (several volts maximum), so each of the LEDs will be reliably protected from breakdown.

LEDs should be placed as close to each other as possible. Ideally, try to find a dual LED, where both crystals are placed in the same housing and each has its own terminals (although I have never seen such ones).

Generally speaking, for LEDs that perform an indicator function, the amount of ripple is not very important. For them, the most important thing is the most noticeable difference between the on and off states (on/off indication, playback/recording, charge/discharge, normal/emergency, etc.)

But when creating lamps, you should always try to reduce pulsations to a minimum. And not so much because of the dangers of the stroboscopic effect, but because of their harmful effects on the body.

What pulsations are considered acceptable?

It all depends on the frequency: the lower it is, the more noticeable the pulsations. At frequencies above 300 Hz, ripples become completely invisible and are not normalized at all, that is, even 100% are considered normal.

Despite the fact that light pulsations at frequencies of 60-80 Hz and higher are not visually perceived, nevertheless, they can cause increased eye fatigue, general fatigue, anxiety, decreased visual performance and even headaches.

To prevent the above consequences, the international standard IEEE 1789-2015 recommends a maximum level of brightness ripple for a frequency of 100 Hz - 8% (guaranteed safe level - 3%). For a frequency of 50 Hz, these will be 1.25% and 0.5%, respectively. But this is for perfectionists.

In fact, in order for LED brightness pulsations to stop being at least somewhat annoying, it is enough that they do not exceed 15-20%. This is exactly the level of flickering of medium-power incandescent lamps, and yet no one has ever complained about them. And our Russian SNiP 23-05-95 allows light flickering of 20% (and only for particularly painstaking and responsible work the requirement is increased to 10%).

In accordance with GOST 33393-2015 "Buildings and structures. Methods for measuring the pulsation coefficient of illumination" To assess the magnitude of pulsations, a special indicator is introduced - the pulsation coefficient (Kp).

Coeff. pulsations are generally calculated using a complex formula using an integral function, but for harmonic oscillations the formula is simplified to the following:

K p = (E max - E min) / (E max + E min) ⋅ 100%,

where E max is the maximum illumination value (amplitude), and E min is the minimum.

We will use this formula to calculate the capacitance of the smoothing capacitor.

You can very accurately determine the ripples of any light source using a solar panel and an oscilloscope:

How to reduce ripple?

Let's see how to connect an LED to a 220 volt network to reduce ripple. To do this, the easiest way is to solder a storage (smoothing) capacitor in parallel with the LED:

Due to the nonlinear resistance of LEDs, calculating the capacitance of this capacitor is a rather non-trivial task.

However, this task can be simplified by making a few assumptions. First, imagine the LED as an equivalent fixed resistor:

And secondly, pretend that the brightness of the LED (and, consequently, the illumination) has a linear dependence on the current.

Calculation of the capacitance of the smoothing capacitor

Let's say we want to get the coefficient. ripple 2.5% at a current through the LED of 20 mA. And let us have at our disposal an LED on which, at a current of 20 mA, 2 V drops. The network frequency, as usual, is 50 Hz.

Since we decided that the brightness linearly depends on the current through the LED, and we represented the LED itself as a simple resistor, we can easily replace the illumination in the formula for calculating the ripple coefficient with the voltage on the capacitor:

K p = (U max - U min) / (U max + U min) ⋅ 100%

We substitute the original data and calculate U min:

2.5% = (2V - U min) / (2V + U min) ⋅ 100% => U min = 1.9V

The period of voltage fluctuations in the network is 0.02 s (1/50).

Thus, the voltage oscillogram on the capacitor (and therefore on our simplified LED) will look something like this:

Let's remember trigonometry and calculate the charging time of the capacitor (for simplicity, we will not take into account the resistance of the ballast resistor):

t charge = arccos(U min /U max) / 2πf = arccos(1.9/2) / (2 ⋅ 3.1415⋅ 50) = 0.0010108 s

The rest of the period the Conder will be discharged. Moreover, the period in this case needs to be halved, because We use a full-wave rectifier:

t discharge = T - t charge = 0.02/2 - 0.0010108 = 0.008989 s

It remains to calculate the capacity:

C=I LED ⋅ dt/dU = 0.02 ⋅ 0.008989/(2-1.9) = 0.0018 F (or 1800 µF)

In practice, it is unlikely that anyone will install such a large condenser for the sake of one small LED. Although, if the goal is to obtain a ripple of 10%, then only 440 μF is needed.

We increase efficiency

Have you noticed how much power is released through the quenching resistor? Power that is wasted. Is it possible to somehow reduce it?

It turns out that it’s still possible! It is enough to take a reactive resistance (capacitor or inductor) instead of an active resistance (resistor).

We will probably immediately remove the throttle because of its bulkiness and possible problems with the self-induction EMF. And you can think about capacitors.

As you know, a capacitor of any capacity has infinite resistance for direct current. But the AC resistance is calculated using this formula:

R c = 1 / 2πfC

that is, the larger the capacity C and the higher the current frequency f- the lower the resistance.

The beauty is that in reactance the power is also reactive, that is, it is not real. It seems to be there, but it is as if it is not there. In fact, this power does not do any work, but simply returns back to the power source (outlet). Household meters do not take it into account, so you won’t have to pay for it. Yes, it creates an additional load on the network, but this is unlikely to bother you as an end user much =)

Thus, our do-it-yourself LED power supply circuit from 220V takes the following form:

But! It is in this form that it is better not to use it, since in this circuit the LED is vulnerable to impulse noise.

Turning on or off a powerful inductive load located on the same line as you (air conditioner motor, refrigerator compressor, welding machine, etc.) leads to the appearance of very short voltage surges in the network. Capacitor C1 represents almost zero resistance for them, therefore a powerful impulse will go straight to C2 and VD5.

Another dangerous moment arises if the circuit is turned on at the moment of the voltage antinode in the network (i.e. at the very moment when the voltage in the outlet is at its peak value). Because C1 is completely discharged at this moment, causing too much current to flow through the LED.

All this over time leads to progressive degradation of the crystal and a decrease in the brightness of the glow.

To avoid such sad consequences, the circuit must be supplemented with a small quenching resistor of 47-100 Ohms and a power of 1 W. In addition, resistor R1 will act as a fuse in case of breakdown of capacitor C1.

It turns out that the circuit for connecting an LED to a 220 volt network should be like this:

And there remains one more small nuance: if you unplug this circuit from the socket, then some charge will remain on capacitor C1. The residual voltage will depend on the moment at which the power supply circuit was broken and in some cases may exceed 300 volts.

And since the capacitor has nowhere to discharge except through its internal resistance, the charge can be retained for a very long time (a day or more). And all this time the Conder will be waiting for you or your child, through which it can be properly discharged. Moreover, in order to receive an electric shock, you do not need to go into the depths of the circuit; you just need to touch both contacts of the plug.

To help the condenser get rid of unnecessary charge, we connect any high-resistance resistor (for example, 1 MOhm) in parallel with it. This resistor will not have any effect on the design operating mode of the circuit. It won't even warm up.

Thus, the completed diagram for connecting an LED to a 220V network (taking into account all the nuances and modifications) will look like this:

The value of the capacitance of capacitor C1 to obtain the required current through the LED can be immediately taken from, or you can calculate it yourself.

Calculation of a quenching capacitor for an LED

I will not give tedious mathematical calculations, I will immediately give you a ready-made formula for capacity (in Farads):

C = I / (2πf√(U 2 input - U 2 LED))[F],

where I is the current through the LED, f is the current frequency (50 Hz), U in is the effective value of the network voltage (220V), U LED is the voltage on the LED.

If the calculation is carried out for a small number of LEDs connected in series, then the expression √(U 2 input - U 2 LED) is approximately equal to U input, therefore the formula can be simplified:

C ≈ 3183 ⋅ I LED / U in[µF]

and, since we are doing calculations for Uin = 220 volts, then:

C ≈ 15⋅I LED[µF]

Thus, when turning on the LED at a voltage of 220 V, for every 100 mA of current, approximately 1.5 μF (1500 nF) of capacitance will be required.

For those who are not good with mathematics, the pre-calculated values ​​can be taken from the table below.

Table 2. Dependence of the current through the LEDs on the capacitance of the ballast capacitor.

C1	15nF	68 nF	100 nF	150 nF	330 nF	680 nF	1000 nF
I LED	1 mA	4.5 mA	6.7 mA	10 mA	22 mA	45 mA	67 mA

A little about the capacitors themselves

It is recommended to use noise suppression capacitors of class Y1, Y2, X1 or X2 for a voltage of at least 250 V as damping capacitors. They have a rectangular housing with numerous certificate markings on it. They look like this:

In short:

• X1- used in industrial devices connected to a three-phase network. These capacitors are guaranteed to withstand a voltage surge of 4 kV;
• X2- the most common. Used in household appliances with a rated network voltage of up to 250 V, withstand surges of up to 2.5 kV;
• Y1- operate at rated mains voltage up to 250 V and withstand pulse voltage up to 8 kV;
• Y2- a fairly common type, can be used at mains voltages up to 250 V and can withstand pulses of 5 kV.

It is permissible to use domestic film capacitors K73-17 at 400 V (or better yet, at 630 V).

Today, Chinese “chocolate bars” (CL21) are widely used, but due to their extremely low reliability, I highly recommend resisting the temptation to use them in your circuits. Especially as ballast capacitors.

Attention! Polar capacitors should never be used as ballast capacitors!

So, we looked at how to connect an LED to 220V (circuits and their calculations). All the examples given in this article are well suited for one or more low-power LEDs, but are completely inappropriate for high-power luminaires, for example, lamps or spotlights - for them it is better to use what are called drivers.

In the photo you can see many LED lamps. I got them as a gift. It became possible to study the design of these lamps, electrical circuits, as well as repair these lamps. The most important thing is to find out the reasons for failure, since the service life indicated on the box does not always coincide with the service life.

MR-16 type lamps can be disassembled without any effort.

Judging by the label, the lamp is model MR-16-2835-F27. Its body contains 27 SMD LEDs. They emit 350 lumens. This lamp is suitable for connection to an alternating current network of 220-240 V. Power consumption is 3.5 W. Such a lamp glows white, the temperature of which is 4100 degrees Kelvin and creates a narrowly directed flow due to the flow angle of 120 degrees. The type of base used is “GU5.3”, which has 2 pins, the distance between which is 5.3 mm. The body is made of aluminum, the lamp has a removable base, which is secured with two screws. The glass that protects the lamp from damage is glued at three points.

How to disassemble LED lamp MR-16

To identify the cause of the breakdown, it is necessary to disassemble the lamp housing. This is done without much effort.

As you can see in the photo, a ribbed surface is visible on the body. It is designed for better heat dissipation. We insert a screwdriver into one of the ribs and try to lift the glass.

Happened. You can see the printed circuit board, it is glued to the case. Prying it with a screwdriver, it separates.

Repair of LED light bulb MR-16

One of the first to be disassembled was the lamp, the LED inside of which had burned out. The printed circuit board, which is made of fiberglass, burned through.

This lamp will be suitable as a “donor”; the necessary spare parts will be taken from it to repair other lamps. The LEDs on the remaining 9 lamps also burned out. Since the driver is intact, the cause of the breakdown is the LEDs.

Electrical circuit of the LED lamp MR-16

To reduce lamp repair time, it is necessary to create its electrical circuit. It's pretty simple.

Attention! The circuit is connected to the network phase by galvanic means. It is prohibited to use it to power any devices.

How does the scheme work? A voltage of 220 V is supplied to the diode bridge VD1-VD4 through capacitor C1. Then it is supplied to the LEDs HL1-HL27, which are connected in series in the circuit. The number of LEDs can be about 80 pieces. Capacitor C2 (the larger the capacitance, the better) is a smoother for rectified voltage ripples. It eliminates the flicker of light having a frequency of 100 Hz. R1 was set to discharge C1. This is necessary in order to prevent electric shock when replacing the lamp. C2 is protected from breakdown of R2 in the event of an open circuit. R1, R2 do not accept work as such in the circuit.

C1 - red, C2 - black, diode bridge - housing with four legs.

Classic driver circuit for LED lamps up to 5 W

The electrical circuit of the lamps does not have protection elements. You will need a 100-200 ohm resistor, or better yet two. One will be installed in the connection circuit, the second will serve as protection against current surges.

Above is a circuit with protective resistors. R3 protects the LEDs and C2 capacitor, R2 in turn protects the diode bridge. This driver is perfect for lamps whose power is less than 5 W. It will easily power a lamp with 80 SMD3528 LEDs. If you need to reduce or increase the current, manipulate capacitor C1. To eliminate flickering, increase capacity C2.

The efficiency of such a driver is less than 50%. For example, the MR-16-2835-F27 lamp requires a 6.1 kOhm resistor with a power of 4 W. Then the driver will consume power that exceeds the power consumption of the LEDs. Due to the large release of thermal energy, it will not be possible to place it in a small lamp body. In this case, you can separately make a housing for this driver.

It should be remembered that the efficiency of the lamp directly depends on the number of LEDs.

Finding faulty LEDs

After the protective glass has been removed, you can inspect the LEDs. If the slightest black speck is detected on the surface of the LED, it has failed. Inspect the soldering areas and check the quality of the leads. 4 poorly soldered LEDs were found in one of the lamps

LEDs with black dots were marked with a cross. Upon external inspection, the LEDs may be intact. Therefore, you need to call them with a tester. To check, you will need a voltage of a little more than 3 V. A battery, battery, or power supply will do. A current-limiting resistor with a nominal value of 1 kOhm is connected in series behind the power source.

We touch the LED with the probes. In one direction the resistance should be small (the LED can glow), in the other it should be equal to tens of megaohms.

During the test, the lamp must be secured. A bank can come to the rescue.

You can check the LED without special instruments if the device driver is intact. Voltage is applied to the lamp base, the LED leads are short-circuited with tweezers or a piece of wire.

If all LEDs are visible, the shorted one is faulty. But this method is suitable if 1 LED in the circuit fails.

If a failure of several LEDs is detected in the circuit, the lamp will light. Only its luminous flux will decrease. Just short-circuit the pads to which the LEDs were soldered.

Other malfunctions of LED lamps

If upon inspection it turns out that the LEDs are working properly, then the problem is in the driver or the soldering area.

Cold soldering of the conductor was detected in this lamp. Soot, which appeared due to poor soldering, settled on the board tracks. To remove the soot, you needed a cloth moistened with alcohol. The wire was desoldered, tinned and soldered. This lamp worked.

Of all the lamps, one had a driver failure. The diode bridge was replaced by 4 “IN4007” diodes, which are rated for a current of 1 A and a reverse voltage of 1000 V.

Soldering SMD LEDs

To replace a faulty LED, you need to unsolder it without damaging the printed conductors. This can be done with difficulty with a regular soldering iron; it is better to put a tip made of copper wire on the soldering iron.

When soldering the LED, you must pay attention to the polarity. Install the LED at the soldering site, take a 10-15 W soldering iron and heat its ends.

If the LED is burnt and the board is charred, this area should be cleaned. Because it is a conductor. If the pad is delaminated, solder the mono LED to the “neighbors”. This is done if the paths lead exactly to them. Just take a piece of wire, fold it two or three times and solder it.

Analysis of the causes of failure of LED lamps MR-16-2835-F27

According to the table, we can conclude that lamp failures often occur due to failure of LEDs. The reason for this is the lack of protection in the circuit. Although there is space for a varistor on the board.

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

The technology for repairing a corn lamp differs from the repair of the lamp shown above.

Repairing such a lamp is simple, since the LEDs are located on the body. And dialing does not require any extra steps. This lamp was disassembled purely out of interest.

The technique for checking “corn” is no different from that described above. Only in the body of these lamps there are 3 LEDs. When ringing, all 3 should light up.

If one of the LEDs is found to be broken, short-circuit it or solder in a new one. This will not affect the life of the lamp. The lamp driver does not have an isolating transformer. Therefore, any touching of the LED tracks is unacceptable.

If the LEDs are intact, the problem is in the driver. In order to inspect it, it is necessary to disassemble the body.

To get to the driver, you need to remove the bezel. Pry it with a screwdriver at the weakest point, it should come off.

The driver has the same circuit as our first lamp with the difference that C1-1µF, C2- 4.7 µF. The wires are long, so the driver can be pulled out without effort. After work on replacing the LED, the rim was installed with Moment glue.

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

Repairing a 12 W lamp is done according to the same scheme. No burnt-out LEDs were found on the case, so I had to open the case to inspect the driver.

There are problems with this lamp. The driver wires were too short and the base had to be removed.

The base is made of aluminum. It was attached to the body using a core. Therefore, it was necessary to drill out the fastening points with a drill whose diameter is 1.5 mm. Next, the base was pryed off with a knife and removed. The wires inside had to be cut.

Inside there were 2 identical drivers, each of which powered 43 diodes.

The driver is wrapped in a heat-shrinkable tube, which had to be cut.

After troubleshooting, the same tube is placed on the driver and crimped with a plastic tie.

The driver circuit includes protection. C1 protects against pulse surges, R2, R3 against current surges. During the testing work, R2 breaks were noticed. Most likely, a voltage exceeding the norm was applied to the lamp. There was no 10 ohm resistor, so a 5.1 ohm resistor was soldered in. The lamp lit up. Next we needed to connect the driver to the socket.

First of all, the short wires were replaced with longer ones. The drivers were connected by supply voltage. To attach the wires to the threaded part of the base, you need to clamp them between the plastic housing and the base.

How to connect to the central contact? Aluminum cannot be soldered, so the wire was soldered to a brass plate in which a hole was drilled for M 2.5. A similar hole was drilled in the contact. The whole thing was screwed together. Next, the base was put on and secured to the lamp body with a cap. The lamp was operational.

Repair of LED lamp series “LLB” E27 6 W 128-1

The design of the lamp is ideal for repairs. The housing is easy to disassemble.

You should hold the base with one hand and turn the protective shade counterclockwise with the other.

Under the body there are five rectangular boards on which LEDs are soldered. The rectangle is soldered to a round board on which the driver circuit is located.

To gain access to the LED terminals, you need to remove one of the covers. To make work easier, it is better to remove the board located at the driver voltage supply points. The photo shows that this wall is parallel to the capacitor body and is separated from it at the maximum distance.

To remove the board, you need to warm up the soldering areas with a soldering iron. Then, to remove it, we heat up the soldering on the round board and it disconnects.

Access to check damage is open. The driver is designed according to a simple design. Checking its rectifier diodes, as well as all the LEDs (there are 128 of them in this lamp) did not show a problem.

When I inspected the solder joints, I discovered that they were missing at some points. These places were soldered; in addition, I connected the printed circuit board tracks at the corners.

When you look at the light, these paths are clearly visible and you can easily determine which path is which.

Before assembling the lamp, it was necessary to test it. To do this, a jumper was installed on the board, and the soldered part of the lamp was connected to the power source with two temporary wires.

The lamp lit up. All that remains is to solder the board in its original place and assemble the lamp.

Repair of LED lamp series “LLB” LR-EW5N-5

In appearance, the lamp is made with high quality. The body is aluminum and the design is beautiful.

The lamp is assembled securely. Therefore, to disassemble it, you need to remove the protective glass. To do this, insert the end of a screwdriver between the radiator. The glass is fixed here without glue, with a collar. You need to rest the screwdriver on the end of the radiator and lift the glass up, using the screwdriver as a lever.

The tester did not show any failure of the LEDs. So it's all about the driver. To get to it, you need to unscrew 4 screws.

But failure overtook me. Behind the board there was a radiator plane. It is lubricated with a paste that conducts heat. I had to collect everything I had unwound. I decided to disassemble the lamp from the base side.

In order to remove the base, I had to drill out the core points. But he didn't act. As it turned out, it was fastened to plastic with a threaded connection.

The radiator had to be separated from the plastic adapter. To do this, I cut with a hacksaw in the place where the plastic was attached to the radiator. Then, by turning the screwdriver, the parts were separated from one another.

The pins were unsoldered from the LED board, which made it possible to work with the driver. Its circuit was more complex compared to other drivers. Upon inspection, a swollen capacitor 400 V 4.7 µF was found. It has been replaced.

The Schottky diode "D4" type SS110 was damaged. It's at the bottom left of the photo. It was replaced by the analogue "10 BQ100", which has 1 A and 100 V. The light bulb lit up.

Repair of LED lamp series “LLB” LR-EW5N-3

The lamp is similar to the "LLB" LR-EW5N-5, but its design has been changed.

The protective glass is secured with a ring. If you pick up the junction of the ring and the glass, it can be easily removed.

The printed circuit board is made of aluminum. There are nine crystal LEDs on it, numbering 3 pieces. The board is secured with 3 screws to the heatsink. The check did not reveal any problems with the LEDs. So it's a driver issue. Experience in repairing a similar lamp has shown that it is better to immediately unsolder the wires that come from the driver. The lamp was disassembled from the base side.

The ring connecting the base and the radiator was removed with great effort. At the same time, a piece broke off. And all because it was screwed with 3 screws. The driver has been removed.

The screws are located under the driver; you can reach them with a Phillips screwdriver.

This driver is based on a transformer circuit. The check showed the serviceability of all parts except the microcircuit. I didn't find any information about her. The lamp was set aside as a donor.

Repair of LED lamp series "LLC" E14 3W1 M1

This lamp is similar to an incandescent lamp. The first thing you notice is the wide metal ring.

I started disassembling the lamp. The first step was to remove the lampshade. As it turned out, it was placed on the base with an elastic compound. After I took it off, I realized that it was in vain.

The lamp contained 1 LED, the power of which was 3.3 W. It could be checked from the base side.

The lamp was attached to the body using a “left-hand” thread. You need to rotate the base counterclockwise when looking at it from the side of the central contact.

The cause of the breakdown was a wire that fell off the thread on the base. You can't solder aluminum, so you had to look for a way to fasten the wire.

A 5 cm piece was soldered to the existing wire for extension. A hole was drilled at the core point, the diameter of which was 2 mm. A wire was threaded through it and wound around a screw. The screw itself was inserted into the hole and clamped with a nut. This lamp glowed like new.

Repair of LED lamp series “LL” GU10-3W

The “LL” type lamp GU10-3W was difficult to disassemble in appearance. The glass began to crack the moment I tried to remove it.

What does the marking mean?

• G - presence of a pin socket;
• U - energy saving lamp;
• 10 – size between pins (measured in mm)

Thanks to the expansion pins, the lamp is held firmly in the socket.

This lamp could be disassembled using a drilled hole. The drilling location was at the level of the printed circuit board. The diameter was chosen to be 2.5 mm. When drilling, you need to take into account the fact that the drill can damage the LED. If you don’t have a drill, you can make a hole with an awl.

A screwdriver is inserted into the hole made. Using it as a lever, you need to lift the glass. If no problems are found when checking the LEDs, remove the printed circuit board.

Burnt 160 ohm resistors were found in both lamps. Based on their size, it could be established that their power is 0.25 W. It does not correspond to the power that is released when the lamp is operating.

The board was filled with silicone, I did not disconnect it. I replaced the burnt resistors with more powerful ones. In one lamp I used a resistor of 150 Ohms and 1 W, in the other 2 parallel soldered ones of 320 Ohms and 0.5 W.

To avoid short circuits, the resistor terminals were coated with silicone. It acts as an insulator.

You can find 2 types of silicone on the market: liquid in tubes and solid, shaped like a rod. The good thing about the rod is that it can be separated with a soldering iron and applied to the desired surface. After hardening it becomes strong.

Both lamps were glowing. All that remains is to attach the board and put on the protective glass.

To secure the boards, I use liquid nails “Mounting” moment. After drying, this glue has plasticity and good heat resistance.

The glue is applied with a screwdriver. In about 15 minutes he will hold our part.

In order not to hold the board until the glue has completely dried, I fix it with silicone at some points. The glass was glued using liquid nails, and the lamp became operational.

The circuit of a 220 V LED lamp allows you not only to understand the operating principle of this device, but also to make it yourself. Attempts to make E27 type light bulbs on your own are due to the fact that it is not always possible to purchase a lighting device with the necessary characteristics. And just those who like to “tinker” with electronics are not averse to trying something new.

• Important nuances
• Scheme
  • With diode bridge
    • LEDs
  • Resistor

Important nuances

There are many systems according to which LED lighting operates on alternating current with a nominal value of 220 Volts. Moreover, all of them, together with the ballast circuit, are designed to solve three main problems.

• Convert 220V alternating current into pulsating current;
• Level out the pulsating current, making it constant;
• Achieve current levels of 12 Volts.

If you want to build a device that is powered by a regular network, you will have to deal with some basic problems to connect it.

1. Where to place the circuits and the LED-based device itself. After all, diodes will need their own place.
2. How can you isolate an LED lighting device?
3. How to ensure the necessary heat exchange for connecting a lamp.

Of course, you can safely purchase the popular E27 lamp. This diode device is one of the most popular on the market and works perfectly from a regular household network.

Scheme

To assemble a circuit and get an LED device based on it for lighting a house using a 220-volt power supply, you will need:

• Equalize alternating current;
• Achieve the required power parameters;
• Provide the necessary resistance.

All this can be done in two ways. There are two main variations.

To save on electricity bills, our readers recommend the Electricity Saving Box. Monthly payments will be 30-50% less than they were before using the saver. It removes the reactive component from the network, resulting in a reduction in load and, as a consequence, current consumption. Electrical appliances consume less electricity and costs are reduced.

1. Circuit based on a diode bridge.
2. A resistor circuit where a specific number of LEDs are used.

They are quite simple, so the device can be assembled without any problems.

With diode bridge

• The diode bridge design includes 4 multi-directional LEDs;
• The task of the bridge is to make a pulsating current from a sinusoidal alternating current;
• Half-waves are conducted through 2 diodes, due to which the minus loses its polarity;
• In the circuit, it is necessary to connect a capacitor to the plus side on the side of the AC source in front of the diode bridge;
• Before the minus, a resistance with a nominal value of 100 Ohms is installed;
• The parallel bridge, behind it, will need to attach another capacitor. It will smooth out voltage surges;
• With basic skills in working with a soldering iron, assembling such a circuit will not be difficult for a novice craftsman.

LEDs

• The LED board can be used as a standard one, borrowed from a non-functioning lamp;
• Before assembly, be sure to check each element for functionality. To do this, use a 12 Volt battery;
• If there are non-working components, their contacts need to be unsoldered and new ones installed;
• Pay special attention to the cathode and anode legs. They should be connected in series;
• If you are simply replacing several parts of an old lamp, it is enough to replace non-working elements with functioning ones by installing them in their old places;
• If you decide to assemble the device yourself, remember an important rule - LED lamps are connected in series in groups of 10, after which the circuits should be connected in parallel.

As a result, your diagram should look like this.

1. 10 LEDs go in one row. Then the legs of the anode and cathode are soldered so that there are 9 connections and 1 tail along the edges, which are in a free position.
2. All resulting circuits are connected to wires. The ends of the cathode go to one, and the ends of the anode go to the other.
3. Don't forget that the cathode is positive and connected to the negative. The anode is negative and must be connected to positive.
4. Make sure that the ends soldered together in the diagram do not touch other ends. If such a situation happens, the circuit will burn out and a short circuit will occur.

Resistor

The electronic ballast circuit can provide the required power for LED lamps powered by 220V.

Creating ballast and connecting here is not difficult, so a relatively newbie in the field of electronics can handle such a task.

• The resistor circuit for LEDs consists of a pair of 12K resistors and a pair of chains;
• The chains consist of the same number of LED elements;
• LED elements are soldered in series and have different directions;
• On the R1 side, one strip of LED elements is soldered with the cathode, and the second strip with the anode;
• The second tap going to R2 is done in reverse;
• Due to this scheme, the glow of LED lamps is soft. This is due to the fact that the LED elements begin to burn one by one, so the pulsating flashes are practically invisible to the human eye;
• A similar LED device, powered by 220 Volts, can be used to illuminate a desktop or illuminate certain areas. Therefore, they can replace traditional lamps, obtaining light of similar efficiency or even a glow of higher quality;
• Practice shows that the resistor circuit of an LED device is most effective when using at least 20 LEDs. It is even preferable to use 40 elements;
• Due to such a number of LEDs and circuit features, you get high-quality lighting. There are absolutely no problems with assembling the circuit, everything is very simple;
• The only nuances of a circuit with 20-40 LEDs is that soldering must be done very carefully so as not to damage adjacent contacts. Plus, putting it all together into a single compact body is another challenge.

Before you continue reading, be sure to read this information. Any source of electricity is dangerous to life if safety rules are not followed. The LED circuits described here do not have transformers and are therefore dangerous. The assembly of such circuits can be performed by people who have basic knowledge of the basics of electrical engineering.

A light-emitting diode is an electronic device that emits light when current is passed through it. LEDs, despite their small size, are extremely efficient, very bright, and at the same time consist of cheap and accessible electronic components. Many people think that LEDs are just ordinary light-emitting bulbs, but this is not true at all.

History of LEDs

Captain Henry Joseph Round, one of the pioneers of radio, noticed an unusual glow emitted by silicon carbide during an experiment. He published his observations in General World, but he could not explain the nature of the phenomenon.

Russian scientist Oleg Losev observed the emission of light from crystals - diodes. In 1927, he published details of his work in a Russian magazine and filed a patent for the “Light Relay.”

In 1961, the infrared diode was created by B. Biard and G. Pitman. However, Nick Holonyak is rightfully considered the founding father of the LED. His student J. Craford created a yellow LED in 1972. At the end of the 80s, thanks to the research of the Russian scientist Zh. I. Alferov, new LED materials were discovered, which gave impetus to the further development of LEDs.

In the early 70s, green LEDs were first invented; in 1971, blue LEDs appeared, which were very inefficient. A breakthrough was made by Japanese scientists only in 1996, who invented a cheap blue LED.

Working principle of LED

The most common LEDs are composed of gallium (Ga), arsenic (As) and phosphorus (P). An LED is a PN junction diode that emits light instead of the heat generated by a conventional diode. When the PN junction is in forward bias, some of the holes combine with the N-region electrons, and some of the N electrons combine with the P-region hole. Each combination emits light or photons.

How does a 220 volt LED lamp work? LEDs are polarized and therefore do not work if they are connected in reverse. The easiest way to check the polarity of a common LED is to determine the thickness of the electrodes by eye. The cathode (-) is thicker. Light is emitted from the cathode. The thinner electrode is the anode (+). Some manufacturers produce LEDs in such a way that the lengths of the cathode and anode wires are different, the anode (+) is longer than the cathode (-). This also makes it easier to determine the polarity. Some manufacturers make both electrode wires the same length, in which case you can determine the polarity using a multimeter.

Advantages and disadvantages of LED lamps

Advantages of LED:

Disadvantages of LEDs:

• May be unreliable for outdoor applications with large temperature variations.
• The need to additionally use radiators to protect semiconductors from thermal effects.

LED is used in a wide variety of applications:

Mains powered LED lighting

But to build an LED lighting circuit, it is necessary to build special power supplies with or without regulators, transformers. As a solution, the diagram below shows the design of a mains-powered LED circuit without the use of transformers.

220 V LED lamp circuit

To power this circuit, 220 V alternating current is used, which is supplied as an input signal. Capacitive reactance lowers the AC voltage. Alternating current is supplied to the capacitor, the plates of which are continuously charged and discharged, and the associated currents are always flowing into and out of the plates, causing reactance against the flow.

The response produced by a capacitor depends on the frequency of the input signal. R2 dumps the accumulated current from the capacitor when the entire circuit is turned off. It is capable of storing up to 400V, and resistor R1 limits this flow. The next stage of the DIY LED lamp circuit is a bridge rectifier, which is designed to convert the AC signal to DC. Capacitor C2 serves to eliminate ripples in the rectified DC signal.

Resistor R3 serves as a current limiter for all LEDs. The circuit uses white LEDs, which have a voltage drop of about 3.5 V and consume 30 mA of current. Since the LEDs are connected in series, the current consumption is very low. Therefore, this circuit becomes energy efficient and has a low-cost manufacturing option.

LED lamp from waste

LED 220 V can easily be made from non-working lamps, the repair or restoration of which is impractical. A strip of five LEDs is driven using a transformer. In a 0.7 uF / 400V circuit, polyester capacitor C1 reduces the network voltage. R1 is a discharge resistor that absorbs the stored charge from C1 when the AC input is turned off.

Resistors R2 and R3 limit the flow of current when the circuit is turned on. Diodes D1 - D4 form a bridge rectifier that rectifies the reduced AC voltage, and C2 acts as a filter capacitor. Finally, Zener diode D1 provides LED control.

The procedure for making a table lamp with your own hands:

LED for car

Using LED strip, you can easily make homemade beautiful exterior lighting for your car. You need to use 4 LED strips of one meter each for a clear and bright glow. To ensure waterproofness and strength, the joints are carefully treated with hot-melt adhesive. Correct electrical connections are checked with a multimeter. The IGN relay is energized when the engine is running and turns off when the engine is turned off. To lower the car voltage, which can reach 14.8 V, a diode is included in the circuit to ensure the longevity of the LEDs.

DIY LED lamp 220V

The cylindrical LED lamp ensures a correct and uniform distribution of the generated illumination over all 360 degrees, so that the entire room is evenly illuminated.

The lamp is equipped with an interactive function surge protection, providing ideal protection for the device against all AC surges.

40 LEDs are combined into one long chain of LEDs connected in series one after the other. For an input voltage of 220 V, you can connect about 90 LEDs in a row, for a voltage of 120 V - 45 LEDs.

The calculation is obtained by dividing the rectified voltage of 310 VDC (from 220 VAC) by the forward voltage of the LED. 310/3.3 = 93 units, and for 120 V inputs - 150/3.3 = 45 units. If you reduce the number of LEDs below these numbers, there is a risk of overvoltage and failure of the assembled circuit.

How to make a light bulb with your own hands

The circuit consists of a high voltage capacitor, a low reactance resistor to reduce current, two resistors, and a positive capacitor to reduce input voltage and line oscillation. Actually, the surge correction is done by C2, installed after the bridge (between R2 and R3). All instantaneous voltage surges are effectively absorbed by this capacitor, providing clean and safe voltage to the integrated LEDs in the next stage of the circuit.

Parts List:

Homemade LEDs are protected, and their service life is increased by adding a zener diode along the power lines. The zener value shown is 310V/2W, and is suitable if the LED includes 93 to 96V LEDs. For other, fewer LED strings, the zener value needs to be reduced according to the overall LED string forward voltage calculation.

For example, if a 50 LED string is used, and the LED has 3.3 V, then we calculate 50 × 3.3 = 165 V, so a 170 V stabilizer will be enough to protect the LED.

Automatic LED night lighting circuit

The circuit will automatically turn on the lamp at night and turn it off after a specified time using several transistors and an NE555 timer. The circuit is inexpensive and easy to install. LDR is used as a sensor here. During daytime, the LDR will be low, its voltage will drop, and Q1 will be in wiring mode. When the illumination in a room decreases, the resistance of the LDR increases, as does the voltage across it. Transistor Q1 turns off. The base of Q2 is connected to the emitter of Q1 and therefore Q2 is biased and in turn turns on IC1.

NE555 automatically turns on when power is turned on. Automatic start occurs using capacitor C2. The output of IC1 remains high for the time determined by resistor R5 and capacitor C4. When transistor Q3 enters the output of IC1, it turns on, triggers flip-flop T1 and the lamp lights up. The circuit includes a 9-volt battery to power the timer during power failures. Resistor R1, diode D1, capacitor C1 and Zener D3 form the power supply section of the circuit. R7 and R8 are current limiting resistors.

DIY LED lighting circuit

Notes:

1. Preset R2 can be used to adjust the sensitivity of the circuit.
2. Preset R5 can be used to adjust the lamp on time.
3. With R5 @ 4.7M, the turn-on time will be about three hours.
4. L1 power should not exceed 200 W.
5. For BT136 it is recommended to use a heatsink.
6. IC1 must be installed on the holder.

Measures to combat LED flickering

A DIY energy-saving LED lamp has a huge advantage, but you need to work hard so that when using your homemade product, users are not bothered by excessive LED flickering:

To avoid the influence of LED flickering, you should always keep the above points in mind.

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.

driver gauss 12w

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.

Cause of failure	Description	Solution
Voltage drops	Such lamps are less susceptible to breakdowns due to voltage surges, however, sensitive surges can “break through” the diode bridge. As a result, the LED elements burn out.	If surges are sensitive, you need to install one, which will significantly extend the life of the lighting equipment, but also other household appliances.
Incorrectly selected lamp	Lack of proper ventilation affects the driver. The heat it generates is not removed. The result is overheating.	Choose one with good ventilation that will provide the necessary heat exchange.
Installation errors	Incorrectly selected lighting system and its connection. Incorrectly calculated electrical wiring cross-section.	Here the solution would be to unload the lighting line or replace lighting fixtures with devices that consume less power.
External factor	Increased humidity, vibration, shock or dust if the IP is incorrectly selected.	Correct selection or elimination of negative factors.

Good to know! Repair of LED lamps cannot be carried 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.

household multimeters

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.

Soldering Station

But before you repair LED spotlights, chandeliers or lamps, you need to determine the cause of the 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 (resistance) 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. The solution is to replace it 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?

If you have a soldering station or hair dryer, this work 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:

To choose the right LED devices, you need to know not only the general ones. Information about modern models and electrical diagrams of working devices will be useful. 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 tip. 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.

Helpful 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.

LED power supply

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.

You need to pay attention to the technical characteristics of the device - 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. It is located in the technical documentation of the device. This does not present any difficulties - all wires are color-coded, and the contacts are labeled with letters.

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

Article

Return