Is it possible to adjust the brightness of LED lamps with a capacitor. Dimmable LED lights

Today we will try to make a controller that will regulate the brightness of the LED. The materials for this test were taken from the website led22.ru from the article “DIY LEDs for cars.”

Today we will try to make a controller that will regulate the brightness of the LED. The materials for this test were taken from the website led22.ru from the article “DIY LEDs for cars.” The 2 main parts used in this experiment are the LM317 current stabilizer and a variable resistor. They can be seen in the photo below. The difference between our experiment and that given in the original article is that we left a variable resistor for adjusting the light of the LED. In a radio parts store (not the cheapest, but very well known to everyone), we purchased these parts for 120 rubles (stabilizer - 30 rubles, resistor - 90 rubles). Here I would like to note that the Russian-made “timbre” resistor has a maximum resistance of 1 kOhm.

Connection diagram: the right leg of the current stabilizer LM317 is supplied with “plus” from the 12V power supply. An AC resistor is connected to the left and middle legs. Also, the positive leg of the LED is connected to the left leg. The negative wire from the power supply is connected to the negative leg of the LED.

It turns out that the current passing through Lm317 decreases to the value specified by the resistance of the variable resistor.

In practice, it was decided to solder the stabilizer directly onto the resistor. This was done primarily to remove heat from the stabilizer. Now it will heat up along with the resistor. We have 3 contacts on the resistor. We use central and extreme. Which last one to use is not important for us. Depending on the choice, in one case, turning the knob clockwise will increase the brightness, in the opposite case, it will decrease. If you connect the extreme contacts, the resistance will be constantly 1 kOhm.

Solder the wires as in the diagram. The brown wire will go to the “plus” from the power supply, the blue wire will go to the “plus” to the LED. When soldering, we deliberately leave more tin to improve heat transfer.

And finally, we put on heat shrink to eliminate the possibility of a short circuit. Now you can try.

For the first test we use LEDs:

1) Epistar 1W, operating voltage - 4V (at the bottom of the next photo).

2) Flat diode with three chips, operating voltage - 9V (at the top of the next photo).

The results (can be seen in the next video) cannot but rejoice: not a single diode burned out, the brightness is adjusted smoothly from minimum to maximum. To power a semiconductor, the main importance is the supply current, not the voltage (the current grows exponentially relative to the voltage; as the voltage increases, the probability of “burning out” the LED sharply increases.

After which a test is carried out with LED modules at 12V. And our controller works on them without problems. This is exactly what we wanted.

Thank you for your attention!

Previously, room lighting was controlled by a rheostat. A significant drawback of these devices was their high power consumption, regardless of brightness. At minimum lamp power, electricity was consumed in the same amount as at maximum, since most of it heated the rheostat.

Adjusting the lighting in the room

Advantages and disadvantages

Nowadays, an electrical load regulator (dimmer) can be bought at an electrical goods store. It is mainly used to change the brightness of lamps of different types and has the following advantages:

change in lamp intensity;
setting automatic brightness change Automatic light dimmer using a timer;
remote control;
used as a switch and to set lamp glow modes: smooth change, creation of light patterns, blinking;
increasing the durability of lamps due to soft starting;
saving energy consumption.

Regulators have disadvantages:

extraneous interference interferes with the operation of devices that do not have filters;
generation of interference for other devices receiving radio signals;
not all devices save energy;

Dimmer Types

The simplest device with adjustment has a switch and a rotatable knob. The brightness of the regulator depends on the position of the potentiometer. The dimmer is suitable for controlling incandescent and halogen lamps. In terms of power, it is selected at least 15% higher than the connected maximum load. It must have built-in short circuit protection. The simplest option is a fuse.

Dimmer comes in the following types:

Overhead. Most often it contains an auxiliary rheostat and is used for LED strips.
Passage - for large areas of premises.
Two- and multi-channel – selected by the number of lamps and control modes.

Where should you not install dimmers?

In public areas where frequent use will not allow them to perform their basic functions. Everywhere you can install devices for smooth switching of lamps built into switches, which can increase their service life.
In places where there is no certainty regarding the installation of lamps.

Methods of regulation

Mechanical - turn the handle. First, the dimmer is turned on until it clicks, and then the brightness is set. The turn-and-press device is more convenient, since you can use a switch with constant adjustment of the regulator.
Electronic: push-button, keyboard. Can be used as a switch and regulator.
Touch - the control panel implements many different functions.
Remote – control via radio signal or using an IR remote control.

Types of lamps for dimmers

Incandescent and halogen lamps 220V. To change the light intensity, any dimmers can be used, since the load is only active (does not have inductance or capacitance). The disadvantage is that the spectrum shifts towards red as the voltage decreases. The power limit for dimmers is within the range of 60-600 W.
Low voltage halogen lamps. For them, we can use a step-down winding transformer, which requires a regulator capable of operating with an inductive load. It is marked RL. When using an electronic transformer, capacitive loads are installed.

Halogen lamps require a smooth change in voltage, which increases their service life. The latest models determine the type of load and adapt to it, changing the control algorithm. You can simultaneously regulate different groups of lamps: incandescent and halogen.

Fluorescent lamps. If they are started via a switch, a glow starter and an electromagnetic choke, a conventional dimmer and rheostat will not work for them. Here you need electronic ballasts (EPG).
LED bulbs. For them, voltage regulation leads to a change in the spectrum. Therefore, the LEDs are regulated by changing the duration of the supplied pulses. In this case, flickering is not noticeable, since their repetition frequency reaches 300 kHz.

Connecting regulators to the load

The connection to the load is made in series (Fig. a). The regulator works the same way as a switch, but it is advisable to install the latter separately, since if it fails due to frequent switching, you will have to replace the expensive dimmer with a new one.

Dimmer connection diagrams

The main requirement is to maintain polarity. The phase is always connected to the dimmer input terminal, marked with the letter L, and from the output terminal the wire goes to the lamp. The phase can be detected using a voltage indicator.

A switch is often installed in the phase wire gap (Fig. b). It is located closer to the door, and the dimmer is located near the bed for easy control.

You can install another regulator and connect them together in parallel (Fig. c). To do this, 3 wires from each device should be routed into the junction box. Similar switching, similar to pass-through switches, is done in long corridors.

The use of dimmers differs in the number of loads. The single method consists of connecting one device or combined into a common group. The next control method is based on accent lighting to highlight individual zones.

Adjustable room lighting

Dimmer connection

The regulator is mounted in the installation box like a regular switch. First, it is connected when there is no voltage in the supply wires, and then installed in the box. Then the frame and brightness control knob are put on.

The basic scheme for regulating the light intensity of lamps for most conventional devices is the same. The difference is only in the additional parts to provide smoother handling and create stability at the lower limits.

To supply voltage to the lamp, the triac should be opened (Fig. a). To do this, a voltage must be created between the electrodes.

Circuits with triac regulation for incandescent lamps: a – the simplest; b – improved

At the beginning of the positive half-wave, capacitor C is charged through a variable resistor R. When a certain value is reached, the triac opens. At the same time, the lamp lights up. Then the triac closes and a similar situation occurs on the negative half-wave, since semiconductors pass current in both directions.

Thus, the light bulb receives “stubs” of half-waves with a frequency of 100 Hz, which was not the case when a rheostat was used. As brightness decreases, light flickering becomes more and more apparent. To avoid this, parts are added to the diagram, as shown in Fig. b. Triacs are installed according to the current load, and the permissible voltage is 400V.

By selecting the values of resistors and capacitors, you can change the initial and final ignition moments and the stability of the lamp glow.

For LED lamps

Despite the efficiency of LED lamps, garlands and strips, energy saving issues also apply to them. Often there is a need to reduce the brightness of the glow. LED lamps with conventional dimmers do not work and quickly break down during the regulation process. For this purpose, special regulators of two types are used: changing the supply voltage, controlling the pulse-width modulation method - PWM (load switching intervals).

Devices that control illumination by changing voltage are expensive and bulky (rheostat or potentiometer). However, they are poorly suited to low-voltage lamps and turn on only at 9V and 18V.

A modern regulator is a complex device that provides smooth starting of lamps, brightness control and setting light switching modes using a timer.

An LED lamp differs from conventional strips and assemblies, which can only be connected using additional devices. Its main features are as follows:

Availability of standard sockets of types E, G, MR for connection.
Ability to work with the network without additional devices. If the lamp is powered by a voltage of 12V, the auxiliary devices are specified in its characteristics.
The generated luminous flux should not differ significantly from standard values.

To ensure the required operating mode, a driver is built inside the lamp that performs useful functions. If it provides for dimming, this is stated in the passport and on the packaging. The brightness of such lamps can be adjusted using conventional regulators.

If dimming is not provided, you should purchase special control devices with PWM regulation. They differ in installation types:

modular (in distribution panels) with control from remote controllers, remote controls or via special buses;
located in an installation box, like a switch, with rotary or push-button control;
remote units mounted in ceiling structures (for spotlights and LED strips).

PWM-based regulators operate on expensive microcontrollers that cannot be repaired. It is easier to make a homemade device based on a simple microcircuit. The dimmer, based on the NE555 timer, operates stably at a voltage of 3-18 V with an output current of up to 0.2 A.

Dimmer circuit for LED lamps

The frequency of oscillations is ensured by a generator consisting of a resistor and a capacitor. The value of the variable resistor can be used to set the interval between turning on and off the load at output 3 of the microcircuit. The field-effect transistor here serves as a power amplifier, since the microcircuit cannot cope with the load from LED lamps. If the current through them exceeds 1A, the transistor requires a cooling radiator.

For fluorescent lamps

The brightness of the lamps can be adjusted using electronic ballasts, which perform the main function of starting them. A simple diagram is shown in Fig. below.

Controlling a fluorescent lamp using electronic ballasts

The voltage to the lamp is supplied from a frequency generator of 20-50 kHz. The circuit formed by the capacitance and the inductor resonates and lights the lamp. To change the current and thus the intensity of light, you need to change the frequency. Dimming is carried out only after the lamp reaches full power.

The adjustable electronic ballast is created on the basis of the IRS2530D controller with 8 pins. The device is a 600V half-bridge driver with triggering, dimming and failure protection functions. The integrated circuit allows you to implement all the necessary control methods through 8 pins and is used in many ways to change the brightness of lamps.

Block diagram of electronic control of fluorescent lamps

Choice. Video

It is better to learn about the correct choice of dimmers in advance from the video.

When purchasing a dimmer, you should carefully study its technical characteristics and determine what types of lamps it is intended for. Choosing the right device makes it easy to connect it yourself without the help of specialists.

The ability to change the brightness of lighting and create different lighting scenarios is becoming as necessary for a modern home as connecting to an electrical outlet or the Internet. Therefore, it is recommended to install luminous flux regulators or dimmers for LEDs every time you update the wiring in the apartment.

Dimmer functions

The functionality of dimmers depends on the complexity of the device. The simplest ones, which you can do yourself, are used only for stepwise or smooth changes in the intensity of the lamp. More modern models equipped with microcontrollers can perform other tasks:

Fine-tuning lighting. A dimmer helps to adjust the comfortable brightness of lighting fixtures depending on the intensity of natural light throughout the day, the orientation of the room to the cardinal points, the design of the window opening, and the habits and preferences of the owners. This is much more convenient than selecting lamps of the required power for each group of lamps.
Automatic shutdown at a specified time. This feature saves the owner from having to check each room before going to bed/leaving and helps reduce electricity bills.
Saving money on lamps. Working in reduced brightness mode, LED lamps and incandescent lamps are able to perform their functions 3–5 times longer than planned.
Simulation of the presence of owners. The device turns on and off, and also changes the brightness of the lamps connected to it, imitating the actions of people living in the house. The program is designed specifically for those who regularly leave their homes and are afraid of burglars.
Remote control of light: via remote control, voice commands, application on a smartphone. This is convenient not only in large rooms, but also in bedrooms when you don’t want to get out of bed in the evening.

Dimmers can be installed both for an individual lamp/chandelier and for a group of lamps. More often, a separate dimmer is provided for each group of lighting fixtures in each functional area.

In addition to living rooms, concert venues, theater halls, circus arenas and other rooms where smooth adjustment of lighting is necessary for visual effect are equipped with devices of this type.

How does an LED dimmer work?

The principle of operation of the device is based on changing the current voltage in such a way as to cut off the leading (“leading edge control”) or trailing (“falling edge control”) edge of the alternating current sinusoid (“phase cutoff principle”). Thus, when dimmed at 50%, the lamp uses only half of its possible power.

Leading edge dimming is used with low voltage lamps, fluorescent and 230V LED lamps complete with electromagnetic type transformers. Trailing edge dimming is used for the same lamps in tandem with electronic transformers.

The task is performed using a rheostat or a complex of electronic elements. Rheostat-type dimmers are characterized by low efficiency (efficiency factor) and do not reduce energy consumption when lighting decreases, so they are gradually falling out of use. Electronic dimmers work by using a bidirectional thyristor and a PWM (pulse width modulation) system that delays the load activation signal. There is no delay when operating at full power; at 10 percent luminosity it is 9 milliseconds. Thus, the dimmable lamp is constantly turned off and turned on with a slight delay.

For normal operation, the device is equipped with protection against overheating and short circuit.

A dimmer is able to prevent damage to the lamp due to regular voltage drops.

Comparing the advantages and disadvantages

pros	Minuses
Allows you to reduce the energy consumption of the room.	They are expensive, especially programmable models with touch and remote control.
They extend the life of lamps by reducing the intensity of operation, as well as smooth starting when turned on.	They lead to malfunctions and destruction of lamps if the devices are selected incorrectly.
Protect the premises from intrusion by strangers.	Low-cost devices generate electromagnetic interference, which impairs the performance of radio devices.
Provide a decorative effect and eye-pleasing illumination in any room.	Not suitable for use with fluorescent/energy-saving/halogen lamps, since the latter are equipped with a compensation system for a stable glow.
They make the lighting design of the room more interesting and varied.	If the load on the dimer becomes less than the minimum permissible (for example, an incandescent lamp is replaced with an LED), the device will quickly deteriorate without the possibility of replacement under warranty.

If you decide to use a dimmer in your home or office, try not to skimp on devices and use the advice of a sales consultant to choose the best dimmers and lamps for each other. Then you are guaranteed to avoid unpleasant effects.

Types and characteristics of dimmers for LED lamps

When buying a dimmer, keep in mind that devices for incandescent lamps, energy-saving lamps and LEDs differ from each other. Therefore, you need to take either a specialized device, or select LED lamps marked “DIMMABLE”/circular icon to match the standard one.

This icon on the box means that the LED lamp will work with a universal dimmer. Minimum luminosity level may vary or not specified

Demonstration of working with different types of lamps

Classification of regulators

Depending on the control principle of the devices, dimmers for LED lamps are:

Turn-push. The most common type of dimers, such devices are easy to operate, have a low price and simple design. The controls are intuitive: the brightness is changed by turning the knob, turning on/off is done by pressing. Users appreciate the ability to turn lights on and off without changing the selected brightness setting.
Keyboards. The devices resemble ordinary switches, which allows you to choose the most suitable dimmers, switches and sockets for your design. The desired degree of brightness is set with the +/- key, switching on and off with the I/O button (or the unlabeled key).
Sensory. The devices are controlled using a tactile-sensitive screen, on which auxiliary information can be displayed. Dimmers of this type are distinguished by a modern, sometimes even futuristic design, and therefore are often installed in modern interiors.
Remote. Such devices are not installed in the user’s direct access area; they are mounted near the lamp or in the electrical panel of the apartment. Control occurs using a remote control or from any gadget via WiFi (you will need to download and install the appropriate application).

Choosing the right type of dimmers depends on your convenience, the design of the room and the budget allocated for the devices.

Devices are also classified according to installation method:

Modular ones are designed for installation in a distribution panel on a DIN rail (next to circuit breakers). Such devices can be installed or replaced at any time; you only need to provide a separate wire for it during repairs.
Wall mounted ones are installed in the same way as sockets and switches directly in the room where the light flux will be regulated. Installation is carried out upon completion of repairs simultaneously with the specified devices. Adding such a dimmer after renovation is very difficult, since it will require chipping the wall and destroying the finish coating.
Remote ones look like miniature (2–3 cm long) blocks with three control sensors. Since they can be controlled remotely, they are installed under a suspended/stretch ceiling next to a chandelier or inside the housing of a lighting fixture. Dimmers of this type can be installed simultaneously with the lamp (there is no need to ditch the walls, so no repair work is required).

If you are planning to equip a smart home system, modular models are suitable for you; If you are planning a renovation without a smart home, prefer wall-mounted ones; if the repairs have already been made, only remote ones can be installed without any risk to the finishing.

Popular dimmer manufacturers

Legrand (Legrand). The French company offers products of European quality, certified according to GOST. Advantages of Legrand dimmers: ease of installation, reliable operation, attractive design (colors: ivory, white, aluminum). The manufacturer offers models of rotary, push-button and touch types.

Schneider Electric (Schneider Electric). The German manufacturer is known for the quality and high reliability of its dimmers. Several series of devices have been developed with different designs and seven color variations. The devices are equipped with mounting tabs and guides that facilitate the installation procedure.

Makel (Makel). The Turkish brand has a more loyal pricing policy than European manufacturers. Experts recommend using devices of this brand in low-load areas, where they demonstrate sufficient reliability.

Each manufacturer includes information on their dimmers about their compatibility with various types of lighting devices. It is usually provided by brand representatives or point-of-sale consultants.

How to choose a device

When selecting a dimmer, it is necessary to take into account the following parameters:

Planned load (total power of connected lamps). The documentation for the dimmer indicates the load power of the device; it should be one third greater than the sum of the powers of the lamps it controls. It is no longer worth making a power reserve, as this will lead to damage to the dimmer.
Mains voltage. LED lamps are designed for 220V or 12V circuits (operate through a transformer). Dimmers for them are produced differently, so make sure that the box is marked 220V.
Compatible with lighting fixture. The instructions for the device should state that it works specifically with LED lamps (not diodes or strips), and not with incandescent lamps.

The choice of dimmer by type of installation and brand is described above. For maximum compatibility of devices, we recommend buying a set of dimmers and lamps at the same time and checking their joint operation in the store.

DIY connection

Installing a dimmer is not difficult for an ordinary electrician or even a person who is only slightly familiar with such work. To connect an external dimmer, it is enough to connect the wires, connecting one side to the wiring, and the opposite side to the lamp (so that the “phase” and “zero” do not get confused, all wires are marked). Modular, as already mentioned, are mounted on a DIN strip in the electrical panel. It is better to entrust this work to a professional so as not to accidentally disrupt the operation of neighboring elements.

The procedure for installing a wall regulator is similar to working with a regular outlet. Let us describe in more detail the operating rules and safety requirements:

identify the phase wire with an indicator screwdriver;
turn off the power supply to the room/apartment (depending on the capabilities of the panel);
connect the phase conductor and the dimmer wire with the “L” marker, and connect the neutral conductor to the wire marked “N”. This can be done by twisting (provides a larger contact area for the conductors) or with special clamps (more convenient and faster, especially for beginners).
place the device in the socket and adjust its position using the adjusting bolts;
install the decorative cover;
connect the power and carry out the experiment.

If your dimmer allows you to turn the light on/off, it is installed instead of a standard switch; if the model only supports the mode of changing the degree of illumination, it is mounted in series with the switch (in front of it).

Detailed instructions for connecting a dimmer (video)

With this knowledge, you can easily find the right dimmer and make your home more comfortable and technologically advanced.

Ecology of consumption. Home: Dimmers not only bring convenience to the environment, but also help save up to 30% of electricity

After the advent of incandescent lamps, manufacturers almost immediately came up with a device that would regulate their brightness. The first dimmers were devices that absorbed electricity. Today everything is much simpler. On the market you can find a wide range of this product that you will definitely like. LED dimmers are also considered common and are used for LED lighting fixtures.

In this article you will find detailed information about their device. Today, these products can include a number of features that will make your life easier. In this article, you will learn how to choose the right dimmer for LED lamps?

Compatibility of LED lamps with dimmers

You should never confuse an LED bulb with simple LEDs. The LED lamp is an independent device that simply needs to be connected to electricity. Here are its main similarities with other products:

The LED lamp also has a standard E-threaded base.
You can easily connect this product in your home. It can be used to work in a standard electrical network.
The luminous flux of this device is also similar to conventional lamps.

An LED lamp will primarily consist of a diffuser for diodes. These devices may also have different power ratings. In order to find out which dimmer for LED lamps is better, you will need to know the power of the lamp. When purchasing this product, you must see what the manufacturer indicates on this device. In order for you to easily adjust the brightness of the lighting in a standard lighting system, LED dimmers were invented. Also, an LED lamp must have this function. The manufacturer usually indicates this on its packaging. Here's what might be written on the packaging:

It is possible to adjust the brightness.
The device is "Dimmable".
The lamp supports the Dimmable function.

Also, those lamps that support this function have an inscription on the box, which can be seen in the photo below.

These lamps already have a light control function. That is why you can easily control it even with a regular dimmer. Dimmable lamps are much more expensive than regular products. But here you can save on the use of dimmers. A dimmer for LED lamps will cost significantly more, since it has a special PWM control in its design.

Popular 220 Volt LED dimmers

LED dimmers today can have a huge range. Dimmers can also be divided by type of installation:

Modular dimmers for LED lamps are installed in distribution panels. These devices can not only adjust brightness, but also perform a wide range of other functions. You can easily control this device using a remote controller.

Typically, these devices are produced only for controlling LED lamps. In domestic conditions they are used quite rarely, as they have a high price.

Monoblock dimmers for LED lamps are also considered a fairly common product. This type is considered the most common.

You can install it instead of a regular lamp. In order to use this device to control an LED lamp, you will need a PWM function.

LED dimmers can also differ in the way they are controlled. Here are their main varieties:

Rotary. The control process will take place using a handle.
Turn-push. The control process in this device will take place by pressing and turning the knob.
Keyboards. By pressing keys you can increase or decrease the brightness of the lighting.
Sensory. These products are considered more modern. With their help you can also take advantage of other functions.

The dimmer circuit for LED lamps is no different from the circuits of other products. In the photo below you can see this diagram.

LED dimmers and their compatibility with lamps

Not every dimmer can work with LED lamps. In order to do this, you will need either a regular dimmer for special lamps or a dimmer that has a PWM function. But there are other problems. For example, some companies produce LED lamps that can only work with a specific dimmer. Typically, sellers of these products should have special tables to help determine compatibility.

When selecting a dimmer, you also need to take into account its power. Here are some tips to help you make the right calculations.

But the best method for verification is considered to be the empirical method. To do this, come to the store with a lamp and check its operation.

Application of dimmers

LED dimmers today have a fairly wide range of applications. Here are the main problems that can be solved using a dimmer:

With their help you can easily organize a flexible lighting system. Also, a dimmer will help to divide the room into certain zones using light.
With its help you can easily organize a design solution.

Modern devices have a fairly high efficiency. The PWM principle avoids overheating and noise generation.
Their use significantly increases the level of comfort.

LED dimmers can also be integrated with the Smart Home system. This allows the implementation of various lighting systems. The only drawback that can be highlighted is the price of these devices.

conclusions

The use of these devices is considered fully justified due to their cost-effectiveness.
The most effective way to adjust brightness is the PWM system.
When choosing these products, it is better to give your preference to well-known brands.
Before proceeding with installation, it is better to additionally check their connection.

If you skip the details and explanations, the circuit for adjusting the brightness of the LEDs will appear in its simplest form. This control is different from the PWM method, which we will look at a little later.
So, an elementary regulator will include only four elements:

power unit;
stabilizer;
variable resistor;
directly the light bulb.

Both the resistor and the stabilizer can be purchased at any radio store. They are connected exactly as shown in the diagram. Differences may lie in the individual parameters of each element and in the method of connecting the stabilizer and resistor (with wires or soldering directly).

Having assembled such a circuit with your own hands in a few minutes, you can make sure that by changing the resistance, that is, by rotating the resistor knob, you will adjust the brightness of the lamp.

In an illustrative example, the battery is taken at 12 Volts, the resistor is 1 kOhm, and the stabilizer is used on the most common Lm317 microcircuit. The good thing about the circuit is that it helps us take our first steps in radio electronics. This is an analog way to control brightness. However, it is not suitable for devices that require finer adjustments.

The need for brightness controls

Now let’s look at the question in a little more detail, find out why brightness adjustment is needed, and how you can control the brightness of LEDs differently.

The most famous case where a dimmer for multiple LEDs is needed is in residential lighting. We are used to controlling the brightness of the light: making it softer in the evening, turning it on at full power while working, highlighting individual objects and areas of the room.
It is also necessary to adjust brightness in more complex devices, such as TV and laptop monitors. Car headlights and flashlights cannot do without it.
Adjusting the brightness allows us to save electricity when we are talking about powerful consumers.
Knowing the adjustment rules, you can create automatic or remote control of the light, which is very convenient.

In some devices, it is not possible to simply reduce the current value by increasing the resistance, since this may lead to a change in the white color to greenish. In addition, an increase in resistance leads to an undesirable increase in heat generation.

The way out of a seemingly difficult situation was PWM control (pulse width modulation). Current is supplied to the LED in pulses. Moreover, its value is either zero or nominal - the most optimal for glow. It turns out that the LED periodically lights up and then goes out. The longer the glow time, the brighter it seems to us that the lamp shines. The shorter the glow time, the dimmer the light bulb shines. This is the principle of PWM.

You can control bright LEDs and LED strips directly using powerful MOS transistors or, as they are also called, MOSFETs. If you need to control one or two low-power LED light bulbs, then ordinary bipolar transistors are used as keys or the LEDs are connected directly to the outputs of the microcircuit.

By rotating the rheostat knob R2, we will adjust the brightness of the LEDs. Here are LED strips (3 pcs.), which are connected to one power source.

Knowing the theory, you can assemble a PWM device circuit yourself, without resorting to ready-made stabilizers and dimmers. For example, such as is offered on the Internet.

NE555 is a pulse generator in which all timing characteristics are stable. IRFZ44N is the same powerful transistor capable of driving high power loads. The capacitors set the pulse frequency, and the load is connected to the “output” terminals.

Since the LED has low inertia, that is, it lights up and goes out very quickly, the PWM control method is optimal for it.

Ready-to-use dimmers

A regulator that is sold ready-made for LED lamps is called a dimmer. The frequency of the pulses created by them is high enough so that we do not feel flickering. Thanks to the PWM controller, smooth adjustment is possible, allowing you to achieve maximum brightness or dimming of the lamp.

By installing such a dimmer into the wall, you can use it like a regular switch. For exceptional convenience, the LED brightness control can be controlled by a radio remote control.

The ability of lamps based on LEDs to change their brightness opens up great opportunities for holding light shows and creating beautiful street lighting. And it becomes much more convenient to use a regular pocket flashlight if you can adjust the intensity of its glow.