How to install an illuminated light switch. Illuminated switch for LED lamps

There are backlit switches on sale, but rarely does anyone get around to replacing one that is already installed without backlighting and is still in good working order.

After spending half an hour, anyone who wants to improve the comfort of night life will be able to add lighting to the switches in their apartment on their own, even without the skills of an electrician.

You can install the backlight switch according to one of the proposed schemes. The circuits differ not only in configuration, but also in technical characteristics. For example, an LED circuit may not work if the luminaire contains LED lamps. And energy-saving lamps may flicker or glow faintly in the dark. Let us consider in detail the advantages and disadvantages of each of the schemes.

Switch illumination circuit based on LED and resistance

Currently, lighting switches are usually equipped with LEDs, which are included in the switch according to the electrical diagram below.

When the switch is in the “Off” position, the current passes through resistance R1, then through the LED VD2, which lights up. Diode VD1 protects VD2 from reverse voltage breakdown. R1 of any type with a power of more than 1 W, rated from 100 to 150 kOhm. With the R1 rating indicated on the diagram, the current flows about 3 mA, which is quite enough for a clearly visible glow in the dark. If the LED glow is insufficient, then the resistance value must be reduced. VD1 of any type, VD2 of any type and color of light. In order to understand the theory and independently calculate the size and power of the resistor, you need to read the article “The Law of Current Strength”.

An LED switch illumination circuit can be installed if the lamp uses incandescent light bulbs. If there are compact fluorescent (energy-saving) ones, then it is possible that in the dark you may notice their faint glow or blinking. If the lamp is equipped with LED bulbs, then the backlight made according to this scheme may not even work, since the resistance of the LED bulb is very high and a current of sufficient strength for the LED to glow may not be created. In the dark, the LED light may glow faintly. The scheme is very simple, but has a big drawback: it consumes a lot of electricity, about 1 kW×hour per month. This is what the assembled circuit looks like.

All that remains is to connect the ends that point down to the switch terminals. If you did not make any mistakes during installation, the circuit will work immediately. I specifically posted a photo of the twists for those who do not have the opportunity to solder the connections with a soldering iron. For reliability and safety, you still need to solder the twists and cover the bare wires and resistor with electrical tape.

Switch illumination circuit using an LED and a capacitor

To increase the efficiency of the backlight in the switch, you can install an additional capacitor in the electrical circuit, while reducing the value of resistor R1 to 100 Ohms.

This circuit differs from the above by using capacitor C1 as a current-limiting element instead of a resistor. R1 here performs the function of limiting the capacitor charge current. Resistance R1 can be used from 100 to 500 Ohms with a power of 0.25 W. Instead of a simple diode VD1, you can install an LED, the same as VD2. The efficiency of the circuit will not change, and both LEDs will shine at once with the same brightness.

The advantage of a circuit with a capacitor is low energy consumption, about 0.05 kW×hour per month. The disadvantages of the scheme are the same as those presented above and, in addition, large overall dimensions.

Switch illumination circuit for a neon light bulb (neon)

The backlighting circuit for a switch on a neon light bulb (neon) is devoid of the disadvantages inherent in the LED backlighting circuits presented above. This switch illumination scheme is suitable for chandelier switches and any other types of lamps, with both incandescent light bulbs and energy-saving fluorescent and LED lamps installed in them.

When the switch is open, current flows through resistance R1, the discharge lamp HG1 and it lights up. R1 of any type with a power of more than 0.25 W, rated from 0.5 to 1.0 MOhm.

In the photo you see the assembled switch illumination circuit, which couldn’t be simpler. It is enough to connect a resistor in series with a neon light bulb of any type and the circuit is ready.

Where to get a neon light bulb

Neon gas-discharge bulbs (neons) are presented in a wide range and you can use any of them available. Please note that on the left in the photo there is a gas-discharge light bulb with a 200 kOhm resistor, removed from a failed computer extension cord switch, which is also called the Pilot. It can be successfully installed in any switch without the additional hassle of finding components. The same light bulbs with a resistor are installed in electric kettles and other electrical appliances to indicate the on state. In the center of the photograph, a Small-sized Thyratron (triode) with a Cold Cathode MTX-90 unexpectedly appeared. To be fair, I’ll say that the MTX-90 thyratron has been shining in my sconce for decades.

Neon bulbs (neons) surround us almost everywhere. Are you surprised? All older fluorescent light fixtures use a starter, which is a real neon light bulb housed in a cylindrical housing. In order to remove it from the lamp body, you need to turn the cylinder slightly counterclockwise. There are as many starters as there are fluorescent lamps in a luminaire. In the starter, a capacitor is also connected in parallel to the neon lamp; it serves to suppress interference and is not needed in the manufacture of the indicator.

If the starter is taken from an old lamp, before using a neon bulb, do not be lazy to check it. Before installation, you must connect the light bulb according to the above diagram. It is better to take a neon from a new starter, since in old ones the glass of the bulb bulb from the inside is usually covered with a dark coating and the glow will be less visible. A light bulb from a starter can be successfully used to make your own phase indicator.

A ready-made lighting kit for installation in a wall switch can be taken from a faulty modern electric kettle. As a rule, most models have a water heating indicator. The indicator is a neon light bulb with a current-limiting resistor connected in series and this circuit is connected in parallel to the heating element. If you have a faulty electric kettle lying around in your household, then a neon light bulb with a resistor can be removed from it and mounted in the switch.

The photo shows three neon lights from electric kettles. As you can see, they shine quite brightly, so in the dark they will be visible in the switch from a great distance.

If you look closely at the insulating tubes placed at the junction of the terminals of the neon light bulb with the wires, you will notice a thickening on one of the tubes. A current-limiting resistor is located at this location. If you cut the tube lengthwise, a picture will open, as in this photo.

Step-by-step instructions for installing in a backlight switch

When working on the switch, you must turn off the power supply!

Neon light bulbs come with a base and without a base, in which the leads come directly from the glass bulb. Therefore, the method of their installation is somewhat different.

Installing a neon light bulb with flexible leads into a switch

As a rule, the length of the leads of a neon light bulb (neon) or LED is not enough for direct connection to the switch terminals and therefore they must be extended with a piece of copper wire. For these purposes, both single-core and stranded wire of any cross-section are suitable. The best way to connect the wire to the terminal is by soldering.

Before soldering, the terminals of the neon light bulb and the ends of the conductor must be cleaned of oxides and tinned with solder using a soldering iron. Then join to a length of at least 5 mm and solder.

Then the soldering point and the terminal of the neon light bulb need to be insulated by putting an insulating tube on them. You can simply wrap a couple of turns of insulating tape.

For ease of soldering, the end of the soldered conductor is formed into a ring using pliers and secured to the switch terminal.

The keys or covers of wall switches are usually made of white plastic and the light from a neon bulb (neon) or LED passes through them well. It is enough to make the switch key visible in the dark. Therefore, there is no need to drill a hole in the switch opposite the backlight installation location.

An insulating tube is also placed on the soldered resistor or it is insulated with insulating tape. The end of the output is formed into a ring and secured to the second terminal of the switch.

The switch illumination circuit is installed, the switch is connected to the electrical wiring, all that remains is to install the key and the work can be considered complete.

Installing a neon light bulb with a socket into a switch

It is not advisable to use a socket for illumination, since the service life of a neon light bulb (neon) is longer than the service life of the switch, and there is not enough space in the box. Therefore, it is more advisable to connect the base to the circuit using soldering.

To do this, you need to remove the insulation from the wires, tin the bare ends and make small loops. Then solder the light bulb terminals on the base to the soldering points.

A resistor is soldered to the wire extending from the central contact of the base at a distance of 2-3 cm. The resistor leads need to be shortened and wire loops made at the ends. A wire is also soldered to the second terminal of the resistor.

The threaded part of the base and the resistor must be insulated. This can be done using heat-shrinkable tubing, insulating tape, or the method I suggest.

Many good polyvinyl chloride (PVC) tubing is often used to insulate wires. To prevent the tube section (cambric) from slipping, the internal diameters should be slightly smaller than the insulated solder. There are always difficulties in finding a cambric of suitable diameter.

But if you hold the cambric for about 15 minutes in acetone, it becomes elastic and can be easily put on a part that is one and a half times larger than its internal diameter. This is how I insulated light bulbs in a homemade New Year's garland in the distant past.

After the acetone evaporates, the cambric again returns to its original size and tightly fits the lamp base. It is no longer possible to remove the cambric unless it is re-soaked with acetone. This insulation method is similar to heat-shrinkable tubing, but no heating is required.

After the preparatory work, the backlight is placed in the switch box and connected to its contacts.

If there is not enough space to place a resistor or you do not have the required power at hand, then the resistor can be replaced with several of lower power, connecting them in series or in parallel.

When resistors of the same resistance are connected in series, the power dissipated on one resistor will be equal to the calculated power divided by the number of resistors, and their value will decrease and will be equal to the calculated value divided by the number of resistors. For example, according to calculations, a resistor with a power of 1 watt and a nominal value of 100 kOhm is required. 1 kOhm = 1000 Ohm. This resistor can be replaced with two 0.5-watt, 50-kOhm resistors connected in series.

When connecting resistors of the same resistance in parallel, the power is calculated as with a series connection, and the value of each resistor must be equal to the calculated value multiplied by the number of resistors connected in parallel. For example, to replace one 100 kOhm resistor with three, the resistance of each must be 300 kOhm.

When installing the circuit, connect the resistor (capacitor) only to the phase wire of the switch. Since the currents flowing through the circuit elements do not exceed several milliamps, there are no special requirements for the quality of the contacts. If the box with the switch in which the backlight will be mounted is metal, then it is necessary to exclude the possibility of the current-carrying conductors touching its walls.

It is impossible to spoil anything when installing the backlight in a wall switch, since the lamp itself is a current limiter. The worst thing that can happen is the failure of the mounted elements if serious mistakes are made. For example, turn on the LED without a current-limiting resistor, or the resistor value is mistakenly taken to be 100 ohms instead of 100 kOhm.

Calculator for calculation
current limiting resistor parameters

When installing it yourself in a backlight switch on an LED or neon light bulb, it is necessary to determine the size and power of the current-limiting resistance. The calculation can be done using formulas, but it is much more convenient to calculate the resistor parameters using a special calculator. Just enter the parameters and get the finished result. The calculator can also be useful for selecting a resistor in a factory-made backlit switch in case the resistor fails.

Reference. On an LED the voltage drop is in the range of 1.5-2 V, on a neon bulb it drops 40-80 V. The required minimum current at which the LED is guaranteed to glow is 2 mA, for a neon bulb - 0.1 mA. This data can be used for calculations on a calculator if the parameters of an LED or neon bulb are unknown.

When choosing a resistance, it becomes necessary to determine its value by color marking. An online calculator will help solve this issue.

Illuminated switches for electrical appliances

Illuminated switches are often installed in switches on carriers and extension cords, heaters and other electrical appliances. They usually have a neon light bulb with resistors built into them. I once had to repair a Pilot type extension cord in which the switch control key fell out and cracked.

When I disassembled the switch, I did not find a current-limiting resistor, which I was very surprised by. Neon bulbs must not be connected to a 220 V electrical network without current limitation. It will fail immediately. On the left photo is a view of the key from the side where the neon light bulb is installed, and on the right, the reverse side of the same switch key.

I measured the resistance between the spring and the terminal of the neon light bulb, it was 150 kOhm. This switch used an interesting design solution: two 150 kOhm resistors were installed in the key holes and a spring pressed them to the terminals of the neon light bulb, ensuring reliable contact. The springs themselves exert pressure on the movable contacts in the switch, from which, when the switch is in the On position, power is supplied to the neon light bulb.

Using a backlight circuit for display

The backlight of the switch performs another additional useful function - it indicates the functionality of the switch and the serviceability of the light bulb. If the backlight works, but the light does not turn on, then the switch is faulty. If the backlight does not work, then the light bulb has burned out.

Any of the above presented circuit options can be used to indicate the health of devices or electrical circuits. For example, if you connect it in parallel with a fuse, then if it blows, the indicator will light up. If an electrical appliance does not have a standard on indicator, then by connecting the indicator immediately after the switch, you can always see whether the appliance is on. When installed in a socket (connected parallel to the current-carrying wires), you will know whether the socket is energized or not.

Even after living in an apartment your whole life, it’s not always possible to turn on the light in absolute darkness right away. Switches with LEDs will help you not to feel the entire surface of the walls every time, and will make it possible to quickly and easily navigate the place using the lighting.

There are factory devices with built-in indicators based on LEDs or lamps. But such a switch is not always suitable for specific operating conditions - 2- and 3-button devices are quite difficult to find.

A simple diagram will help you assemble and connect your switch with an LED. Additional advantages of such lighting are the ability to monitor the health of wiring, lamps and the switch itself. To implement your plan, you will need a few simple radio components and a little time.

What might you need?

There are several ways to connect an LED to a switch. First, you should decide whether the indicator will be inside the housing or outside.

The main role when installing the switch backlight is given to the LED (VD1). It must be connected to the switch terminals through a limiting resistor (R1). The backlight circuit should also include a protective LED (VD1), which will eliminate the trouble of reverse voltage.

The resistor value is selected taking into account the color and brightness of the LED, and the possibility of heating the elements should also be taken into account. Devices of different shades may differ significantly in their basic characteristics. On average, the operating range of the resistor is 100-150 kOhm at a power of over 1 W. If the LED does not shine brightly enough, the resistance value can be reduced slightly.

When developing a lighting scheme, it is worth considering the type of lamp:

• incandescent lamps will operate as usual;
• energy-saving ones may begin to flicker;
• LED-based lighting may not work with this circuit due to the high intrinsic resistance of the elements.

You can eliminate some of the shortcomings of the circuit, increase efficiency and reduce energy consumption (from 1 kW/hour to 0.05 kW/hour per month) by installing an additional capacitor, which will act as a current-limiting element. In this case, the resistor value will also need to be lowered to approximately 100-500 Ohms at a power of about 0.25 W.

The main disadvantage of connecting a capacitor is the increase in the dimensions of the indicator.

Using a similar scheme, illumination of sockets and other interior elements based on LEDs can be connected.

Stages of connecting the backlight

Connecting an LED does not require any special skills; it is only important not to neglect safety rules and perform all actions carefully so as not to damage the existing wiring.

1. Turn off the power supply.
2. Assemble the selected circuit, connect the elements to the switch terminals.
3. To output the LED, a hole with a diameter of about 2 mm should be drilled in the decorative panel of the switch.
4. Insert the LED and secure it with glue if necessary.
5. Assemble the switch.
6. Restore power supply.
7. Check the functionality of the circuit.

The backlight will only work when the light is off, when the light is on, the LED will not be visible.

Switches with LEDs can serve as an impromptu night light, so it is important to carefully choose the brightness and shade of the device. Most often it is red LEDs that are installed, although the choice can be made of green, blue and even ordinary white. More complex circuits will help to implement a separate indication for each key of 2- and 3-button switches, but such backlighting is not particularly popular and has a complex implementation.

In the evening, returning home after work, the first thing you have to do is feel for the switch in a dark room. It’s even worse when you have to get out of bed at night in complete darkness and, half asleep, fumble along the wall to find the switch. Although this is unpleasant, many have already gotten used to it, instead of installing an illuminated switch at home.

Types of switches

On the modern construction market, switches are presented in a sufficient assortment to choose exactly the type that will best suit the local lighting needs of the room. They differ both in appearance and design features - backlit switches photo.

Main types of switches:

• keyboards;
• push-button;
• sensory;
• rotary;
• corded.

In a residential area, a walk-through switch with backlight and all of the listed varieties can also be used, but the most widespread are:

1. Single-key switch with backlight - applicable for closing only one circuit, sold with a built-in diode for night illumination.

2. Two-key switch with backlight - has 2 switches and is used for chandeliers and other multi-lamp fixtures. The connection to the network is designed in such a way that one key can simultaneously turn on 1-2 or more light bulbs, and when the second key is turned on, the rest of the chandelier lights up. Often a two-button switch is used to use a separate bathroom.

3. Three-key or four-key switches - capable of simultaneously closing 3-4 electrical circuits, so they are used to control lighting fixtures in several rooms from one place. For example, for convenience, in one place in the house there is a staircase, a separate bathroom and a hallway. It is most advisable to provide such a switch with backlighting if it is missing.

4. Cord switch - used in sconces and portable lamps, backlighting is usually not used.

Key switches are the most popular, and they are found in almost every apartment or house, in schools and kindergartens, in offices and other public places. Many modern models are sold with a backlight diode and a transparent shield so as not to stain the wall around the switch with your fingers. The touch-sensitive backlight switch is used less often.

Advantages of an illuminated switch

1. The general design and construction of backlit switches is almost the same as conventional models, but a small LED provides a significant advantage when used in a dark room.

2. The light switch indicator is quite economical because the small LED consumes very little electricity.

3. The diode operates only when the switch is not working and automatically goes out when the device is used.

4. We can say that the energy costs for LED self-service are so negligible that it has virtually no effect on electricity consumption.

5. An additional advantage - if a backlit switch is installed in the bedroom, then in the event of a sudden awakening at night, this makes it possible to quickly navigate the space while awake.

About the operating features of circuits for a backlit switch

Visually and structurally, most illuminated switches are almost no different from simpler ones; they are connected to the main wiring in the same way.

The main components of the backlight are:

• small neon lamp;
• LED paired with a resistance element.

They must be powered in parallel with the main contacts of the circuit breaker. If it is in the non-working position, then the LED is powered through the filament inside the diode with low resistance.

To add a little comfort to your home lighting system, you will need to spend no more than half an hour. You can limit yourself to replacing obsolete switches with new, improved ones, that is, diodes. The second option is to independently equip existing switches with a simple element for night lighting. If you know how to connect an illuminated switch, then it’s easy to do it yourself, even without an electrician’s education.

It is important to have a basic understanding of electricity and closed circuits, as well as the ability to read simple electrical diagrams. Each scheme has its own features, components and parameters. But if you connect the illuminated switch incorrectly, then:

• the diode may not light up;
• energy-saving lamps will flicker;
• the sensor glows faintly in the darkness.

The advantages and disadvantages of different schemes are worth examining in detail.

Pass-through switch with backlight

The contact mechanism of this type of switch is characterized by a moving contact, which is always activated when the circuit breaks. By pressing the “on/off” button in such a switch, the moving contact is transferred from one contact to another, ensuring the operation of the second section of the circuit. That is why it is called that - a changeover or pass-through switch.

Pass-through switch with backlight - the connection diagram is fundamentally different in terms of access, here one lamp (chandelier) can be controlled from two places. For example, turn it on at the beginning of the stairs and turn it off on the other side. The pass-through type of switch otherwise performs the functions of closing the circuit and operates the lighting fixture from different sides.

The circuit of a pass-through switch illuminated by diodes is relevant on stairs in 2-story rooms or more. This is convenient because the staircase can be illuminated from both the lower and upper floors. In this case, it is advisable to place the switch at a distance of approximately the same place from the first step of the stairs, so as not to stumble in absolute darkness while looking for the switch key. The same applies to corridors, the lighting of which can be conveniently controlled from both ends.

The installation diagram is quite simple: at the beginning of a long corridor there is a 1st switch, at the other end there is a 2nd pass-through switch with an LED. When the network closure elements are disconnected, the lamp does not light up - there is no closed circuit for the flow of current. When the first switch is moved to the operating position, there is a closed contact - the light will light, and if the second switch is activated, it will go out. The easiest way to install a backlit switch is to use ready-made models with a built-in diode.

Diagram of operation of an LED switch with resistance

Most illuminated switches come pre-installed with LEDs, which must be connected to the electrical circuit during installation. When the switch is in an inoperative position, current must flow through the resistive element, while the diode is protected by reverse voltage.

With a minimum current strength of within 3 mA, a noticeable glow of the switch in the dark is ensured. If the brightness of the diode is not enough, it is important to reduce the resistance value. In this case, you need to have basic knowledge of the physics of current, or you can refer to reference literature - tables on current strength calculations.

This backlit switch connection diagram is applicable only for a chandelier with a traditional incandescent lamp. However, when using LBU neon lamps or energy-efficient lamps, problems are possible - at night either a slight flickering or the lamps spontaneously turning on and blinking will be noticeable.

When the luminaire is designed for LED lamps, the internal lighting on the switch may not work. This is due to the network resistance, which for an LED light bulb is quite large in itself, and there will be a lack of current to ensure operation of the sensor in a closed network.

Features of the installation diagram of a switch on an LED with a capacitor

For productivity, experts recommend placing another capacitor directly into the switch in the electrical circuit, reducing the value of the resistor. The fundamental difference in the circuit is the use of an element instead of a resistor to limit the current using a capacitor.

Instead of one simple diode, it is enough to install another LED, described above, while the circuit will remain unchanged, but both LEDs will glow with the same intensity. The advantage of this type of connection of a diode with a capacitor is efficiency. The disadvantage is the larger size and inefficient operation of the LED.

Installation of a backlit switch

For those who are interested in how to install an illuminated switch, just use the diagrams and tips given in the article. They can be installed instead of conventional switches that require replacement, or they are obsolete. And those wires that come from the backlight are connected to the switch contacts in parallel with the main power wires.

Attention: Before starting work on installing the switch, be sure to turn off the power supply to the network!

1. It is important to decide what type of light bulb the new switch will regulate. Not all of them work equally well with the indicator - due to the large resistance, as discussed in previous sections. The best option is to work with halogen and incandescent lamps, and backlit switches will work flawlessly when paired with them. And with LED and fluorescent lamps, problems with the ballast of the lighting device are possible - the lamps will flicker.

2. For a glowing indicator, you need to calculate the current-limiting resistance in a closed network before installing the switch yourself. You can use ready-made formulas or calculate the resistor characteristics using a special calculator. To do this, you don’t need to know physics - just enter known parameters into the calculation and get the answer. In addition, this calculator is also useful in determining the resistor parameters of finished switches, for example, when the backlight fails.

3. Sometimes there are no markings on the resistor bulb, but there is a symbol for the characteristics in color. Then the denomination is determined according to the diagram or table of the “online calculator”.

Important to know: The guaranteed current for glowing in LEDs is 2 mA, and for a neon lamp - 0.1 mA. The lower voltage threshold for LED operation is not lower than 1.5-2 volts, and for neon lamps - up to 40-80 V. Data is necessary for other calculations, for example, when the parameters of the luminous element of a finished switch are not known.

4. When a resistor with a high-power resistance is required or is not enough for soldering, replace it with several low-power resistors connected in series. When several resistors are connected in this way, their total power corresponds to the calculated power divided by their number. For example, a 1 V resistor with a nominal value of 100 kOhm can be safely replaced by 2 0.5 Watt 50 kOhm resistors connected in series.

5. When installing a circuit, a resistor or capacitor must be determined where the phase is to connect to that wire. The current passing through the circuit elements is within a few mA, and the quality of the contacts is not decisive here. When installing the backlight in a metal box, it is important to ensure that there is no contact with the walls or conductive conductors.

Attention: It is difficult to fundamentally disrupt anything in the network when installing the backlight, since the lamp here acts as a current limiter. The only thing that can happen if some omissions are made is the inoperative state of the built-in diode. Problems arise when the LED is soldered without a resistor or they have a different value.

Step-by-step instructions for installing a neon light bulb without a base with short leads into a switch

Small neon bulbs that are suitable for mounting in a switch are available without a base or with a base. The difference is that the short wires come out directly from the bulb, then the method of their installation has its own characteristics.

Let's give a more complex example - installing a neon lamp without a base with short wires in a switch:

• for an LED, the length of the output leads is very short, just like a small neon lamp, so they are not enough for a full supply to the switch terminals; for this, they are extended with copper wires (single-core or multi-core);
• Extend the wiring by soldering; before doing this, clean the outputs from oxides and treat them with solder;
• attach a copper wire of the same diameter more than half a centimeter, working with solder;
• Be sure to insulate the soldering (with a tube, a flight one);
• It is convenient to round off the ends for fastening into terminals with round nose pliers, securing them to the switch terminal;
• solder a resistor to the 2nd pin and a piece of wire of the required length to connect to the 2nd pin of the switch;
• also insulate the solder, form a ring and secure it to the second terminal of the switch;
• The last stage is securing with a key.

Tip: Most switches have keys made of thin white or translucent plastic, and under them the light from the diode is clearly visible in the dark. The switch is visible at night when not in operation, and there is no need to drill a hole opposite the neon resistor. As a last resort, use a drill to make a small round cutout on the key and fill it with silicone. This should only be done with the key removed!

When you return home in the evening after work, the first thing you have to do is feel for the switch in a dark room. And at night, you often need to get out of bed and, half asleep in complete darkness, fumble along the wall with your hand to find the button and turn on the light. Sometimes this procedure takes a lot of time, and is often accompanied by falling objects that get in the way. To make it easier to find the location and save time and nerves, an illuminated switch was invented.

Peculiarities

In appearance and design, such devices are practically no different from conventional switches, the only thing is that they are equipped with a light indication, which in the dark immediately catches the eye and indicates their location.

At the same time, the indicator light consumes very little electricity and lights up only when the light is turned off. Therefore, there is no need to worry about the fact that when using this device the electricity consumption will be greater, since the backlit switch consumes almost no electricity.

Types of switches

The modern construction market offers switches in a fairly large assortment, so the buyer can choose the most suitable option for himself. The devices differ not only in appearance, but also in design features.

There are several types of switches:

• push-button;
• keyboards;
• rotary;
• sensory;
• corded.

Pass-through switches with backlight can also be used in residential premises, but among all types they are most widespread:

1. Single-key switches with backlight. Used to close only one circuit. They have a built-in diode for night illumination.

2. Two-key switch with backlight, having two switches. Used for chandeliers and other multi-lamp fixtures. The control principle is that when you press one key, 1-2 or more light bulbs turn on simultaneously, and when you press the second, the rest of the lighting device lights up. Often a two-key switch is used for separate bathrooms.

3. Three- or four-key switches can simultaneously close three or four electrical circuits, so they are used to control lighting fixtures in several rooms from one place. For example, it is very convenient when the staircase, hallway and separate bathroom are included in one place in the house.

4. Cord switch is used in portable lamps and sconces. Backlighting, as a rule, is not used here.

Among all the models, key switches are considered the most popular and widespread. They are available in almost all apartments and houses, in kindergartens, schools, offices and other public places. The backlit key switch is very convenient.

Benefits of using illuminated switches

1. The design and general design of the backlit switch is almost no different from conventional models, but the built-in LED allows you to determine the location of the device even in complete darkness.

2. The luminous indicator is very economical, since the small LED backlight of the switch consumes very little electricity.

3. The diode works only when the device is not working, and when it is turned on, it goes out automatically.

How it works?

Most illuminated switches connect to the main wiring just like regular models.

Main components of the backlight:

• small neon switch illumination lamp;
• LED with resistance element.

The connection to the main contacts of the switch must be parallel. If the device is in the non-operating position, then power to the LED passes through the filament inside the diode with low resistance.

It will take no more than half an hour to add comfort to your home lighting system. You can simply replace obsolete switches with improved (diode-based) models. Another option is to equip existing devices with an element for night illumination. Knowing how to connect an illuminated switch, you can do this yourself, even without an electrician’s education. You just need to have a basic understanding of what electricity is, a closed circuit and be able to read diagrams. Each electrical circuit has its own characteristics, parameters and components. If the illuminated switch is connected incorrectly, the following consequences may occur:

• the diode may not light up;
• energy-saving lamps will flicker;
• in the dark the sensor will glow faintly.

Single-key switch circuit

Let us consider in more detail the operating principle of such a device.

As can be seen from the diagram, the standard version implies a simple break in the phase wire (on the left). If there is an LED backlight for the switch, the diode bulb connects the wire in the “Off” position. Why is the main lighting not on in this case? The answer to this question is quite simple: the diode is soldered together with a resistor, which reduces the circuit voltage to a low value. This is quite enough to power a small light bulb, but there is not enough voltage to ignite a large filament.

Connection

Having understood this device a little and selected a suitable model, you can begin connecting the backlit switch. We offer you to consider step-by-step instructions with which you can easily replace the device yourself:

1. Before starting work, be sure to turn off the electricity at the distribution panel.
2. Then you need to remove the old switch. First, the keys are removed, then you should remove the frame and take out the inner part by unscrewing the clamping screws in advance.
3. Loosen the contacts and release the device.
4. On the back of each switch there should be a connection diagram for this device, according to which the wires need to be connected to the new switch.
5. Let's start installing the new switch. This is done in reverse order.
6. Now you can turn on the switch and check the functionality of the new device and its backlight.

That's all. The main thing in this work is to take your time, and everything will definitely work out.

Pass-through switch with backlight

A distinctive feature of the contact mechanism of this type of switches is the moving contact, which is always activated when the circuit breaks. When you press the On/Off button the moving contact in such a device is switched from one contact to another, thereby ensuring the operation of the second section of the circuit. That's why it got the name - walk-through or changeover switch.

The connection diagram for a pass-through switch with backlight differs fundamentally in access. One lamp (chandelier) can be controlled from two different places. For example, turn on the light at the beginning of the stairs and turn it off on the other side. This type of switch completes the circuit differently and operates the lighting fixture from different directions.

The installation diagram of the device is very simple: the first switch is installed on one side, and the second pass-through switch with an LED is installed on the other end. When the network closure elements are disconnected, the lamp stops burning - there is no closed circuit for the flow of current. When you turn on the first switch, a closed contact appears - the light bulb begins to glow, but if you turn on the second, it goes out.

How to make your own backlight

If you don’t want to get rid of the old switch and want to dig around, then you can make the indication yourself. To do this you need:

1. Remove the switch from the wall.
2. Using a soldering iron, assemble a circuit from a diode and a resistor.
3. Solder the assembled structure to the contacts (input and output).
4. Place the diode lamp in the housing and mount the switch in its original place.

Conclusion

Selecting and connecting a new illuminated switch is very simple. But to do this, you should take into account the capabilities of the electrical wiring, since sometimes it needs to be modernized. And in this case, you can’t do without an electrician. In addition, unexpected surprises may appear, such as blinking lamps. Therefore, before buying brand new switches, consult with specialists.