How to replace LEDs in a chandelier

To repair LED lamps, you do not need to be a qualified electronics engineer or purchase expensive equipment. It won’t be difficult to organize the work at home if you first prepare everything you need and understand the features of the fixtures. The main thing is to take your time and do everything carefully, following the recommendations from the article.

The tester allows you to quickly find a broken diode.

Ceiling chandeliers

Lighting devices with built-in LEDs of this group are the most popular and in demand. In ceiling chandeliers, the main light source can be ordinary incandescent lamps. It is possible to change them to LEDs.

You can carry out the repair yourself. The same can be done with halogen lighting fixtures. LEDs burn very beautifully, which is why chandeliers with them are very popular among users. Lighting lamps of this type emit a gentle light that can be of different shades.

One LED chandelier can have different colored lamps. Most often, lamps of red, blue and green shades are used for this. The combination of these colors in ceiling devices is the brightest and most contrasting. Since LEDs do not burn strongly and do not irritate the eyes, they can be used as night lights. Ceiling lighting fixtures are often installed in children's rooms. Kids love to have colorful lights in their room. LEDs, varying in lighting and power, for a chandelier can be bought at any electrical store.

Preparing for repairs and what is required for this

You need to prepare everything you need for work. Some items may be on hand, others will have to be purchased, but this will not cost much. List of tools and accessories:

A small soldering iron with a small tip. The contacts in the lamps are small, so the standard option will not work. It is best to buy a special model with different types of tips (flat and point). We must not forget about the materials for soldering - solder, rosin, etc.

Soldering iron with a thin tip and USB charging
Set of tweezers. The tool store sells sets of tweezers for small jobs; they have devices of suitable shapes and sizes.
Holder for a lamp or other unit (the so-called “third hand”). A good solution is a device with a magnifying glass to simplify the work. You can adapt available elements - cut off a plastic bottle or pick up something else.
Small gas burner. Models from tobacco kiosks that are used to light cigars are suitable. If you can’t find such a device, buy a so-called “turbo lighter” that does not go out from the wind.
A set of screwdrivers of different sizes to remove and disassemble the lamp. Most often, Phillips-head screws are used as fasteners.

Set of tools for repair.

Some fixtures use hex head screws, so you may also need a set of wrenches. Repairing LED lamps is a scrupulous job, since the products contain many small parts, and if handled carelessly, they can be damaged.

Repair

As already mentioned, modern LED chandeliers are distinguished by their original design. Despite this, almost all devices have a modular design. That is, regardless of the collection and design, chandeliers are assembled from the same type of electronic components. You can adjust the brightness and contrast of lighting in the room, turn on/off one or more groups of lamps using the control panel. The device is very convenient to use. In its design and construction it resembles a regular TV remote control (for an expensive model chandelier).

Typically, LEDs used for chandeliers are connected in series. There can be 10, 20, 50 or more of them in one device. Chandeliers burn from a 220 V network. To reduce the voltage in devices, most often, a quenching capacitor is installed. The scheme has a drawback - a short service life. After a short amount of time, the LEDs go out of tune. Moreover, almost everything. Repairing lighting fixtures involves replacing all lamps. The best LEDs for this are those with a wide lighting angle. They are easy to replace, so repairs will not take much time. Then you need to check whether the chain is connected correctly (the main thing is not to confuse the polarity).

It happens that the main lighting in a chandelier works at a high level, but the LED night lighting does not light up at all. If the modes in the device switch, then the problem is in the power supply. Its repair consists of the following - renewing the connections of the conductors between the LEDs. At the same time, do not forget about safety precautions. Chandelier repairs are best left to professionals. Since devices with a control panel are not very cheap, you need to reduce the risks to a minimum. Specialists will quickly identify the problem why the backlight is not working and carry out high-quality repairs.

Chandeliers with remote control often go out of tune if they are made of poor material. Therefore, when purchasing a lighting device, you should pay attention to the brand and country of manufacture. LEDs used for a chandelier, like other lighting equipment, must have a quality certificate and are officially approved for sale. To avoid making expensive repairs in the future, it is better to immediately request documents for the goods. Chandeliers with a remote control must also have a warranty period (quite long).

Modern lighting fixtures with remote control, which stand out on the construction market with their attractive design and original design - chandeliers with LEDs. They are chosen for residential premises.

How to re-solder an LED correctly

LED bulbs use less energy than incandescent bulbs.
They also last much longer, so owners of houses and apartments are gradually switching to economical lighting. But despite their long service life, LED bulbs can gradually fail due to the burnout of the LEDs installed inside. When one of the chips deteriorates, this is not a reason to throw away the light bulb; it can be repaired. To do this, you will need a tester to determine the breakdown, then you can replace the damaged element or connect the circuit. In the latter case, the repair will negatively affect the life of the lamp; it will shine dimmer. Therefore, it is better to replace the chip with another one. To do this you need to know how to solder LEDs.

How diode elements are arranged

LED lamps have diodes inside them. They are also mounted in rulers and tapes, which are often used in advertising banners. There are no contact pins here. The diodes are mounted on a plastic or aluminum printed tape and are connected to each other with a special track during soldering. Removing an LED or installing a new one is not difficult if you have a gas torch, soldering iron and flux on hand.

The structure of an LED light bulb.

In most cases, LED lamps are made of aluminum, which can provide effective heat dissipation to the radiator. A different number of LEDs are installed inside, which determines the power. The contact terminals of the diode strip have a substrate on the reverse side for heat removal. It is soldered to the heat sink pad. When removing one of the diodes, it will also have to be unsoldered.

Compliance with safety regulations

When repairing any device that is powered from the mains, safety precautions must be observed. LED lighting devices, like incandescent light bulbs, are connected to a 220 volt network. Therefore, the master must be careful and take into account the recommendations:

After turning off the lamp, you must manually discharge the capacitors. To do this, the terminals are short-circuited with a metal device with a dielectric handle.
during the desoldering process, you must not leave the soldering station unattended, as this may cause a fire;
When turning on the installed light bulb, it is better to turn away, as there is a possibility that due to possible mistakes it will explode.

Soldering LEDs is not an easy process for a beginner. Repairs should only be started if you have experience working with a soldering iron and are familiar with the design and operating principle of chips.

How to unsolder and re-solder an LED

Before you start soldering, you need to study the instructions and acquire materials and tools for the work. Don’t forget to check the purchased LEDs. Sometimes craftsmen neglect this rule, which is why the work has to be done twice.

What is needed for work

To desolder an LED from an aluminum board you need:

tweezers;
blade;
soldering iron (recommended with a thin tip);
flux;
holder.

If you don't have a soldering iron with a thin blade, you can make a soldering iron from copper wire.

Soldering iron with a homemade thin nozzle made of copper wire.

Soldering temperature

The indicator diode, which is installed on a printed circuit board, consists of conductive legs and a glass bulb. Outwardly, it resembles a small light bulb. For soldering, you must use a soldering iron with a power of no more than 60 W. The permissible tip temperature is 260 degrees. SMD diodes do not have current-carrying elements. They are replaced by special contact pads on the board. In this case, a 12 W soldering iron is used for soldering.

Step-by-step instructions for desoldering

The first step is to remove the aluminum board. To do this, the lamp body is separated from the lampshade. Here you can use a knife, carefully so as not to damage the elements. The pad is attached to the base using a pair of wires (plus and minus). They should be unsoldered by securing the board to the holder. The board can be removed from the aluminum base without tools.

Disconnected board with LEDs.

Before you start soldering the LED, you need to take a tester and go through all the chips to check their functionality. In most cases, damaged elements can be seen visually. A black dot appears on a burnt-out LED.

Appearance of a burnt-out diode.

It is better to check using a tester, since sometimes a breakdown does not entail visible changes.

Checking diodes with a tester.

It is recommended to pay special attention to the quality of soldering. If there was a defect in production, this will affect the functionality of the chips.

Soldering diagram

When all burnt diodes have been identified, you can begin soldering. The board is fixed on the holder. Afterwards, the burner is carefully brought to the back of the board. After 3-5 seconds, the soldering should loosen, which will make it possible to disconnect the diode. A serviceable element must be secured before the base cools down. To do this, you need to place a drop of flux on the contact pad. The chip is installed on top, taking into account the polarity.

Then it is heated again, while lightly pressing on the crystal. Hold the diode until the contact “legs” are securely fixed in the solder. If there is no LED, you can solder a small piece of wire in its place. The lamp will continue to work, but the light will be dimmer. This option is suitable only if there are more than 10 chips installed on the board.

Removing a damaged LED.

Using the same scheme, diodes from corn lamps are soldered off. This can be done if the light bulb is small and assembled according to a classic design. Instead of a soldering iron, a hair dryer is sometimes used, but it takes more time to work.

Before soldering the chips, the ruler should be secured to prevent damage to the conductor tracks. The tin is melted with a soldering iron, and a blade is simultaneously advanced between the board and the terminal. When all pins are freed, the substrate is disconnected from the board.

Video example: Replacing LEDs in a lamp using an iron.

Common mistakes when soldering

Inexperienced craftsmen often make the following mistakes:

installation of the connector on current-carrying contacts. This will result in a poor connection;
work with a soldering iron heated to 300 °C and above. This will provoke burning of current-carrying threads;
the use of an aggressive solution will lead to corrosion of the contacts;
failure to observe polarity when installing the diode on the board.

In order for the new diode to work for a long time and not burn out, before installing it on the board, the remaining solder should be removed from it. To do this, it is recommended to use braided wire from shielded wire. Errors made during operation can cause the lamp to instantly burn out or explode when turned on.

Ceiling chandeliers

What is a lamp transformer

To provide protection against voltage surges, a transformer is used to normalize the voltage. The device is produced in two types:

Winding. Easy to use (everyone can connect, even without skills in this area), accessible. Contains coils between which a connection is formed, thereby ensuring the operating principle of the device. Disadvantages: large mass, large size, inconvenient to use at home, strong heating during constant operation.
Electronic. Wide area of application, as it is light in weight, size, and does not heat up with constant use. The only drawback is the cost. Some electronic transformers for halogen lamps with surge protection are produced.

These protective devices are not mandatory. But they ensure the durability of halogen lamps.

Repair

Testing the driver and series-connected chandelier LEDs

Hi all! Today’s article will talk about LED radio-controlled chandeliers, or more precisely, about such a part of it as LEDs. A common malfunction of the chandelier when the LEDs stop lighting will be considered. There will be a theory, a diagram, a photo, and a real repair.

The topic of installation and repair of LED chandeliers with a remote control on the Internet (and on my blog) is covered quite widely, but there is practically no information on LEDs and their connection in a chandelier. Now it will definitely be)

I have several articles on chandeliers with a remote control; I will provide links along the way. On the topic of LEDs, I’ll give you a link right away.

Recently I had to repair such a chandelier; the LEDs in it stopped lighting. Based on fresh memory, I will comprehensively consider this issue and share my experience.

Types and main causes of breakdowns

If problems arise with an LED lamp or light bulb, it is impossible not to notice it. The types of faults may vary, but the most common are:

The light disappears completely. This can happen either when turning it on or off, or during operation.
Lighting can disappear at any time and resume after some time. Moreover, the time intervals can be anything.
Flickering of a light bulb or lamp. The intensity may vary, but changing brightness creates visual discomfort.
Flashing is when the light blinks every second.
Damage to the structure due to impact or moisture entering the system (for example, due to condensation or if neighbors from above flooded the apartment).

When some of the light bulbs stop burning, you should not put off repairs.

If there are only a few types of faults, then there are many more reasons. The most common problems that arise are:

Overheating of components and their deformation or contact failure. The diodes do not heat up much (up to about 30 degrees). But if the room is hot, then the temperature under the ceiling can rise to 50-60 degrees, and under such conditions contacts are broken, parts fail and individual elements on the board peel off. The problem also arises when the cooling radiator becomes covered with dust over time or the lamp is located in a place with poor ventilation.
Violation of the recommended rules for using LED equipment. Along with the lamp and chandelier, there are always operating conditions under which the manufacturer guarantees long-term operation. Any deviations increase the risk of malfunctions significantly.
Diode burnout caused by voltage surges or capacitor failure. This is typical for inexpensive models.
Various violations when connecting and installing equipment. Short circuits and other network failures can cause breakdowns.

Important! The cheaper the product used, the higher the likelihood that even the slightest deviation from the norm will lead to malfunction.

When connecting, it is important not to confuse anything.

Don’t forget about manufacturing defects; they are much more common than in other types of lamps. Defects are especially common in lamps with a remote control, since the design is complex, and the technology is often not yet fully developed.

LEDs or LED light bulbs?

Let's first find out what LED bulbs and LEDs are used in chandeliers, and how they are connected, before moving on to practical repair issues.

LED lamp and LED - is there a difference?

The difference is fundamental. Let's figure it out.

What LEDs are used in chandeliers

LEDs are single-color (in chandeliers, blue or white are usually used), two-color (red-blue), and multi-color (for example, red-blue-green). At the end of the article I will give links, you can see what is currently on sale. There is also a lot of background information there.

The supply voltage for single-color LEDs is 2..2.4 V (red, yellow, yellow-green, orange) or 3.0...3.6 V (white, cyan, green, magenta, pink). These two ranges are for LEDs of different colors; they have slightly different physical principles of operation. Accordingly, the brightness of the glow is very different.

Here is a reference table for voltages and other parameters of LEDs, taken from the seller’s website:

Table of LED parameters for chandeliers (and not only!) of different colors.

Forward current (If) of all models is 20 mA . This current is optimal in terms of the brightness/durability ratio. That is, the lower the current, the longer the LED will work. And the more current, the brighter.

Multi-color (multi-color) can be divided into two types, according to the method of switching colors:

LEDs without control, with automatic color switching. Switching can be fast or slow, two or three colors.
LEDs with control, when to turn on one color or another (2 or 3), you need to apply voltage to the desired output of the LED. Voltages, depending on the color, can be different - 2 or 3 Volts.

There are LEDs with a voltage of 5V. This mainly applies to two-color models. Then, the following driver is used:

RB Synchronous double controller – driver for serial LEDs 5 V

This driver says “RB Synchronous double controller” . The number of LEDs is 31-40 pcs, the voltage on each is 5 V. The inscriptions and parameters of such drivers will be discussed in more detail below.

To be honest, I haven’t quite figured out how to use such a driver. I assume that it is the same as the one discussed in the article, only the difference is in the forward voltage, which is not 3V, but 5V. Who can confirm or deny this - please write about your experience in the comments.

There is little specific information on the types of LEDs on the Internet, and it is difficult to use - after all, LEDs are transparent and do not have inscriptions. All that remains is to focus on the sellers’ descriptions (links will be at the end of the article). Or find out experimentally. Below, in the part about repairs, we will tell you how.

The chandeliers use LEDs with a transparent round body, diameter 5 (4.8) mm. Another feature is LEDs in chandeliers without a lens, with a shortened body, like a “straw hat”. They have a wide radiation pattern.

LEDs have wire leads for soldering. Although, in chandeliers they are never soldered, but inserted directly into the “mother” connector. The main thing is to maintain polarity.

LED light bulbs in chandeliers

99% of LED bulbs are 12 V AC or DC. Most often now you come across light bulbs with universal power supply, 12 VDC/VAC, which are powered by a 12 VAC electronic transformer. Such transformers (more precisely, voltage sources, or drivers) are much cheaper than those for direct current.

How to replace a light bulb in a spotlight?

With the advent of cheap LED light bulbs on the market, the question of replacing them arises more and more often. To replace, you must first know the type of base. The figure below shows examples of LED type: E-27, E-14, GU-10, GU-5.3, G-9, G-4, GX53.

When replacing a light bulb, you need to pay attention to what type of lamp was installed in the spotlight. There are several types of spotlights:

LED lamp MR-16 is used in luminaires DL-11;
LED lamp minion E-14, used in recessed spotlights of the R-63 brand;
GX-53 closed type lamps.

Let's look at examples of how to change an LED light bulb in spotlights.

Always turn off the mains power before replacing!

Replacing a GU5.3 or GU10 LED Bulb

Such a base is often secured with a retaining ring. They are secured in the socket with two conductive pins until they click (GU5.3) or by turning 90 degrees (GU10). Replacing them is quite simple using the following instructions.

Replacing E-14 and E-27 lamps

For this type, replacement is even easier. You need to unscrew the old light bulb counterclockwise and screw in the new one clockwise, while de-energizing the room in advance. It is necessary to screw in all the way, without applying any effort.

Pay attention to the base. E-27 is a well-known standard, the diameter is the same as that of a regular incandescent light bulb. E-14 – base with a smaller diameter. If in doubt, take the burned out light bulb with you when purchasing.

Closed type GX53

They are often called a pill. These are some of the easiest lamps to operate and replace. The easiest way to change them is:

Turn off the network power;
We take hold of the lamp and turn it counterclockwise until it stops. The rotation angle is no more than 10-20 degrees and it will freely fall out of the grooves;
insert a new tablet into the grooves and turn clockwise until it stops. Ready.

Base G9 and G4

These miniature light bulbs are similar in design, they differ in size, but their installation principle is the same. Due to their low weight, they are attached only to the socket with the base. Additional fastenings are usually not provided. Let's look at how to replace such a light bulb in a spotlight.

Replacing light in furniture lighting

Any spotlights on furniture and kitchen equipment are replaced in 99% of cases using one of the above methods. The whole difficulty of replacement lies in dismantling the decorative lamp diffuser.

Strict requirements for the appearance of the lamp force designers to hide the fastenings as much as possible and you need to use your imagination to understand how to remove this or that lamp.

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In this regard, it is possible to change halogen bulbs to LED bulbs without any modification at all. If the chandelier uses a transformer with an output voltage of 12 VAC.

LED light bulbs, as a rule, have a G4 connector (more precisely, a base), which was used in halogen lamps.

Why is “applied” in the past tense? Because halogens are now dying out.

Such a light bulb is shown in the photo above. If anyone doesn’t understand, the transparent little belly is on the left)

Parallel or serial connection?

In the comments, my readers often have a question: are the LEDs in the chandelier turned on in parallel or in series? Often, in order to answer this fundamental question, you need to find out what we are talking about - LEDs or LED light bulbs?

We can confidently say that the LED bulbs are switched on in parallel and are powered by a driver (voltage source) of a stable voltage of 12V. The same applies to halogen and any lamps. Not only in chandeliers, but always and everywhere.

Another thing is LED matrices, which are not used in chandeliers, but are mainly used in spotlights. The main thing for power supply there is a stable current.

And something in between - a driver that turns alternating voltage into constant, without any stabilization of voltage and current. LEDs are connected in series to the output of such a driver; it is only important that the number of LEDs be within certain limits. These are exactly the ones used in chandeliers for sequential switching.

If you have come across a chandelier where LEDs were connected in parallel, share your experience in the comments. These are probably some special LEDs.

Okay, enough theory, now the fun part -

Subtleties of replacing halogen lamps with LED lamps

What is important to consider when replacing halogen lamps with LED lamps:

Base . You should choose an LED with the same base as in the original chandelier.
The problem may be the low power consumption of LED assemblies . Some models of electronic transformers are equipped with an automatic shutdown function at low load. With diodes, the chandelier may blink or not work at all. The solution is to remove the transformer and replace it with an LED driver.
Light direction of LED lamps. The angle of distribution of the light flux for halogens is 360°, for LEDs it depends on the design. Choose models with wide-dispersion lenses, preferably with a frosted diffuser, otherwise you will get uneven lighting.
the lampshade design in mind when choosing LED light bulbs. The LED lamp may not fit into its original location or will protrude and look unsightly.
Color temperature of LED lamps. Most LEDs emit cold white light (4000K - 6000K), so it is not advisable to place them in children’s rooms. This is a great option for a living room or office.

The purpose of retrofitting chandeliers is to save electricity. It is worth understanding that upgrading one light source will pay off no earlier than in two to three months (for rooms with constant use of lighting). It is more efficient to reinstall several sections of a living space at once.

There is no need to save money when choosing semiconductor lamps. Miser pays twice. A cheap product produced by an unknown manufacturer is often of low quality and quickly becomes unusable.

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The LEDs in the chandelier stopped lighting

Let's look at it first

Design of a chandelier in which the LEDs do not light up

LED chandelier. LEDs connected in series do not work

If this is your first time seeing a chandelier from the back, I highly recommend my article on the construction of such chandeliers.

In this case, we have the simplest device: a chandelier for 2 groups, the 1st group - for 220V (4 E14 bulbs), the second group - 21 blue LEDs. The LEDs are connected in series through a driver, the device and circuit of which will be given below.

The controller that controls the chandelier using signals from the remote control is as follows:

Controller for a chandelier in which the LEDs do not work.

Not only is the controller Noname, but the label on the diagram is a complete mess; the conclusions should be like this:

red – power phase,
black – zero power,
black – zero load (both wires are equivalent),
white – phase output to load 1,
yellow – phase output to load 2.

Well, to be completely grumpy, the third letter in the word “sacing” is wrong.

If the LED backlight on the chandelier stops working, then first of all you need to make sure that the controller supplies 220V power to the LED driver. Such controllers are easy to repair; read my article about Repairing LED chandelier controllers. There is also an exchange of experience among colleagues.

LED Serial Driver

On the body of this simplest device is the proud inscription LEDDRIVER.

Power supply for series-connected LEDs

In general, the Chinese call any power converters drivers, so there is no need to delude yourself.

Let's take a closer look at what is written on it:

Power supply for LEDs in a chandelier

Let's look at each power supply parameter:

MHEN is a trademark. Identical devices are produced under the brands Jindel, ALED, Junyi, Jing Yi, and under other unpronounceable names.
LED DRIVER – diode driver, as translated by an automatic translator. It may say LED Controller.
21-30 pcs – the number of LEDs that can be connected in series to this device.
Model : GEL-11101A – model, it is also indicated on the board.
Input : AC220-240 V 50 Hz. Everything should be clear here.
Current : DC 60mA Max. This is the maximum current, which is not stabilized in any way; it is stabilized by the LEDs connected to the output. I wrote more about how this happens in the article about the Design and Connection of LED Strips.
Output : Establish DC 3.0-3.2V. In fact, this is the voltage on one LED when the number within the specified limits is turned on (21-30 pcs.).
LED 30 pcs Max – maximum number of LEDs.
Ta, Tc – temperature of the environment and the device body.
Jindel Electric is a Chinese manufacturer specializing in simple, cheap consumer electronics.

Checking the LEDs

A 3V LED is not an ordinary diode. A regular diode can be tested in the forward direction with a multimeter set to the “semiconductor testing” mode, and the readings will be about 800 Ohms. When the LEDs are tested in the forward direction, the LED lights up, albeit dimly. Otherwise, it doesn't light up. The multimeter does not show anything. More precisely, it shows infinity, i.e. "1".

In fact, when testing, a multimeter produces a voltage source of about 2V, and this is quite enough for a working LED to show signs of life.

To make everything completely clear, here's a picture:

Design, dimensions and pinout of an LED for a chandelier.

The anode to which the “plus” power is supplied is longer than the cathode to which the “minus” is supplied. The LED on the left shows a schematic diagram of a diode to make it clearer.

We apply the “plus” of the multimeter to the anode, and “minus” to the cathode. Thus, you can easily find out the polarity of the LED, its serviceability, and color. And based on the color, use the table above to find out the operating voltage.

In the chandelier that I was repairing, I started ringing the diodes, and realized that they would all have to be changed. Some showed 2-3 ohms in both directions, some showed 1000 ohms, some showed infinity. The result of inept repairs. Even if 1 or 2 LEDs are out of order, you should think about replacing everything, because... their parameters have inevitably changed (yes, we are all aging), and the new ones will have different parameters.

As a last resort, 1 or 2 LEDs can be replaced with jumpers or a resistor, the resistance of which will be calculated below. The jumper can only be installed if the remaining number of LEDs is not less than what is indicated on the driver. Otherwise, the “lucky ones” will not burn for long, but brightly.

Elena will also tell us how to check the LEDs in a chandelier:

Checking the Serial LED Power Driver

In general, all LEDs need to be changed. What about the driver?

To make sure the driver + LED tandem works, I assembled (soldered) the following bright design:

Checking the driver and LEDs before installing on the chandelier

As you can see, I use Vago terminals everywhere. Convenient and practical.

So, the measurement data is like this.

The output voltage of the driver (its device and its circuit will be for dessert) at idle (no load) is 305 V DC.

We connect a load of 22 LEDs (see photo above). We get - the voltage at the driver output is 80 V , the voltage on each LED is 80 / 22 = 3.63 V. According to measurements on each diode, this was approximately the case. As you can see, the voltage is slightly higher than the nominal value (3.0...3.4V), because the chandelier should shine brightly!

Now we connect 30 LEDs in series.

LEDs before installation in a chandelier. Connection for testing

Let's send current through the wires:

Checking 30 LEDs before installing in a chandelier

Measurement results. The driver output voltage is 107 VDC , one driver is 3.54 VDC .

That is, in principle, such a driver can power 40 diodes without a noticeable decrease in brightness.

That's it, the next day I installed these diodes with a driver in the chandelier, the owner was happy, and so was I.

Inability to replace LEDs

When using a regular chandelier, you can always replace the bulbs if you are not happy with the color it emits. This cannot be done with an LED chandelier. But it is worth saying that there are chandeliers that come with a remote control. With it you can change the color from “warm” to “cold” and vice versa. But such chandeliers are much more expensive.

Another disadvantage is the inability to change the brightness of the lighting. When purchasing a regular chandelier, you can always buy lamps of higher power. This will not happen with an LED chandelier. You will have to use what you originally purchased. You cannot increase or decrease the brightness of the light.

Source and LED resistance calculations

Thanks to our circuit design teacher, Elena Mikhailovna Shibaeva.

Now, for fun, let’s calculate the output resistance of the power supply and the resistance of the LEDs. The calculations involve the good old Ohm with his famous law and the voltage divider formula.

So, for the case of 30 LEDs we have:

Open circuit voltage of the current source – 305 V,
Current source voltage under load – 107 V,
The current in the circuit (yes, old Kirchhoff with his 1st law!) is 0.02 A.

We know the current from the declared parameters of the diodes, but we cannot rely on this figure for sure. Judging by the voltage on one diode, the current is much more!

To make the calculations clearer, I am attaching a diagram:

Circuit for measuring resistance

We assume that the input of the circuit is supplied with voltage from an ideal EMF source with zero internal resistance. A real source of electricity has an internal resistance Ri, which we will now calculate.

When measuring the open circuit voltage Un = Uхх = 305 V, since the input resistance of the voltmeter is much greater than the internal resistance of the source Ri.

When a load is connected, Un = 107 V, which means that the voltage dropping across the internal resistance of the source Ri is 305 – 107 = 198 V.

Knowing the current, let's calculate the internal resistance:

Ri = 198 V / 0.02 A = 9900 Ohm.

Is it a lot or a little? Everything is relative. In this case - in comparison with the load resistance:

Rн = 107 V / 0.02 A = 5350 Ohm.

This is the resistance of LEDs connected in series when a current of 0.02 A flows through them. This means that the resistance of one LED is 5350 Ohms / 30 = 178 Ohms.

This means that without changing the circuit parameters, one LED can be replaced with a 180 Ohm resistor. This coincides with the value obtained experimentally on one LED: 3.54 / 0.02 = 177 Ohms.

We see that the resistance of the power supply is greater than the load resistance. This means that in front of us is a current source. That is, when the load resistance (the number of LEDs) changes within certain limits, the current remains almost unchanged.

You can calculate the resistance of diodes, when there are 22 of them, it will be less due to the fact that the current will be greater, and the current-voltage characteristic of the diode is nonlinear.

Tricky question. Why, if the calculated resistance of the LED is 178 Ohms, does the tester in continuity mode (Ohmmeter) not show any resistance? Write your answer in the comments, I will be glad to know and savvy readers!

Okay, we've deviated somewhat from the topic.

Now - the promised dessert.

Ice lamp circuit

The usual circuit of an inexpensive Chinese lamp for 220 volts. Instead of a reliable driver, they contain a simple transformerless power supply circuit with capacitors and a rectifier.

The network voltage is first reduced by a non-polar metal film capacitor, rectified, and then smoothed and increased to the desired level. The load current is limited by a conventional SMD resistor, which is located on the printed circuit board with LEDs. When diagnosing and repairing LED lamps of this type, it is important to follow safety precautions, because all elements of the electrical circuit are potentially under high voltage. By carelessly touching the live part of the circuit with your finger, you can get an electric shock, and a slipped multimeter probe can short-circuit the wires with unpleasant consequences.

Device and circuit of the LED chandelier driver.

Driver circuits for LED lamps are also in this article. There these are stabilized current sources.

LEDs just need current, that is, a source with a high output resistance. If the LED is connected to a voltage source (whose output resistance is much lower than the resistance of the diode), then the current after a certain voltage will increase very quickly until the diode burns out.

This is how I burned a diode during laboratory work in physics in the 2nd year)

Power supply (inverter) for sequential switching of chandelier LEDs

And this driver is the simplest device, I soldered these in the 7th grade, in a radio club. It is a stretch to call it a current source, due to the fact that its output resistance is greater than or equal to the load resistance. We calculated this above.

We open it up and see a simple board without a single active element:

Let's disassemble the LED driver

Brown barrels are ballast (limiting) capacitors. They are for an operating voltage of 400 V, a capacitance of 0.33 μF:

LED Driver Limiting Capacitor

On the cases they say 334 and 824, respectively. What does this mean - look for “Alphabetical designations on capacitors”. I wrote about this in an article on repairing a chandelier controller with a remote control, link above.

View from the soldering side:

Driver for powering serial chandelier LEDs. Solder side diagram.

DIY assembly according to the diagram

Each electronic transformer contains instructions that indicate connection rules. The main thing is that between the light bulb and the parting there should be a cable no more than 1.5 meters in length, 1 sq. mm in cross-section. If this condition is not met, the brightness will be lost and the wire will overheat.

When connecting from two halogen lamps, a star circuit is used. It involves connecting a separate cable to each light bulb, while its length is the same. At a distance of more than 1.5 meters, the cable cross-section should be increased. It is stipulated that the distance to the light bulb should not be less than 20 cm.

The best option for a switch with one or two keys is to divide the light bulbs into two identical parts. The connection is made to two 12V converters. Each of the devices is carried out through separate wiring. This connection in the distribution box will facilitate repairs (if necessary).

The figure shows a diagram for connecting 12V halogen spotlights.

Driver circuit for LEDs in a chandelier

The circuit is very simple, maybe it will be useful for someone in repairs:

Driver for powering serial chandelier LEDs. Electric scheme

Briefly the device. Ballast limit chain – C1, C2, R1. Most of the voltage drops on this circuit. Next, the alternating voltage is supplied to the diode bridge, and then to the filter R3, C3, R2.

If you need to slightly increase the voltage at the driver output under load (i.e., reduce its output resistance, see the part of the article with calculations), then you can increase the capacitance of the filter capacitor to 10...20 μF. Then the number of LEDs can be increased slightly.

And if you need to reduce the number of LEDs in a chandelier (for example, some have burned out), then you can reduce the ballast capacity by removing one of the capacitors C1, C2. It's experimental.

LEDs negatively affect the human body

This statement has long been proven by scientists. The blue spectrum of the LED harms the body and immunity. But the consequences are purely individual. For some, such light may not affect, but for others, their sleep patterns will be disrupted and their immunity will even decrease.

When using LED chandeliers in the office, workers are likely to experience decreased productivity, become overly nervous, and fatigue will occur faster.

Cooling radiators

Many models of regulators, drivers and power supplies of LED lamps come with cooling radiators. They have a seat through which a microcircuit or other control element gives off heat. Most lamps have radiators.

The lack of special lubricant and thermal paste is the reason for overheating of the majority (up to 15%) of boards and units. Unscrew and check whether it is applied along the plane of the seat.

Thermal paste is applied in a thin layer over the entire surface of the seat; a large amount will only worsen heat transfer. By screwing an additional thin aluminum plate to the radiator, you can increase heat transfer, while the installation is carried out without blocking the main air flows passing through it.