How to connect a backlit switch: circuit and device

Comfortable conditions can be created from little things, for example, a switch equipped with illumination. This element has many advantages, provided that the correct device is purchased correctly installed.

What are the switches with the on indication

The backlight in electrical switches is a neon or LED. It is almost impossible to visually distinguish them, the only difference is that neon lamps consume less electricity, but create a larger voltage drop. The minimum current for the LED glow is 2 mA, the voltage drop is 2 V, and for neon varieties, these indicators are 0.1 mA and 70 V, respectively. This is important to consider when choosing an electrical switch.

Switches with an indicator may not work correctly with different types of lamps. The design works smoothly and efficiently with halogen and incandescent lamps. It is better to refuse from the operation of LED and energy-saving ones or take special measures. The most common malfunctions - the light blinks in the off position of the switch, the indicator in the switch does not light up.

The backlight can be equipped on all types of switches and with any number of keys. The location of the glowing indicator can be different: at the top or in the middle of the key, in the center or at the bottom of the device body itself.

Illuminated switch device

Connecting a switch equipped with indicator lights is usually straightforward. It is enough to choose a quality model or upgrade an already purchased one.

The backlight in the device consists of neon lamps or resistance LEDs connected in series with each other. This small circuit is connected in parallel with the switch contact. The circuit is always energized, regardless of whether the light is on or off.

If the switch is on, the backlight color is closed by a contact that has a lower voltage. Almost no current flows through the backlight, therefore, it does not burn.

A current-limiting resistor is connected in series with the neon lamp or LED in the switch. It is installed in order to reduce the current to optimal parameters. LEDs and neon lamps require different amperage, so the resistors are set at different ratings.

• For neon bulbs - 0.5-1 MΩ, power dissipation - 0.25 W.
• For LEDs - 100-150 kOhm, the minimum power dissipation is 1 W.

Connecting directly with a resistor is not the best option. This is due to the performance of the circuit, as well as the tendency of the resistor to overheat. It is also possible that a reverse current will flow through the electrical circuit. This will inevitably lead to a breakdown of the LED.

With diode

The first step is to solve the problem of reverse current flow. It is easy to fix it - you need to install the diode in parallel with the LED element.

If you connect the device according to the specified scheme, the power dissipation of the resistor will not exceed 1 W, the resistance will fluctuate within 100-150 kOhm.

It is important to choose the right diode, which, in terms of its technical characteristics, will be similar to the parameters of an LED bulb.

Such a scheme, despite the simplicity of implementation and performance, has a drawback - the backlight consumes a considerable amount of electricity, and the resistor heats up.

This type of illuminated switch is compatible and will work correctly with incandescent lamps. If we talk about economical types and LED chandeliers, then the work will be observed intermittently.

To save electricity with a capacitor

To eliminate the problem of overheating of the resistor, as well as to reduce the amount of energy consumed, the circuit is additionally equipped with a capacitor. In this case, the parameters of the resistor also undergo changes, since its task is to limit the charge of the capacitor.

The resistor value will fluctuate within 100-500 AM, and the capacitor parameters - 1 mF, 300 V. The resistor values ​​are set experimentally.

The advantage of such a scheme is that it practically does not consume electricity. The monthly consumption is about 50 watts. However, placing a capacitor in a very limited space is problematic. Also, the circuit does not guarantee uninterrupted operation with energy-saving and LED lamps.

How to connect an illuminated switch

The principle of operation of the device is based on Ohm's laws. Electric current flows along the path of the smallest resistance when lines with different resistances are connected in parallel.

The connection diagram has the same high resistance, regardless of the type of indicator used - a neon lamp or an LED. This figure is provided by a limiting resistor.

When the switch is opened, the luminaire serves as an ordinary conductor. A current flows through it with a small strength, which is enough for the smooth operation of the backlight.

Where to lead the wires

Before proceeding with the installation of a switch with an indicator, it is important to understand the design. For this, it is recommended to remove the keys. Most often, they are fixed to the body using pins or a latch.

Under the keys you can see the terminals for connecting wires. Almost always, they are visually small copper pads with screws.

To connect the wires, their end must be removed from the insulating layer and the wire must be stripped, held under the screw and the contact plate, and securely fixed with the first. It should be tightened with effort, but the main thing is not to overdo it, the structure is rather fragile. After a while, it is better to check the quality of the connection again and tighten it again, since copper slightly lends itself under the screw.

Connecting a light switch with one key backlit

The wiring diagram is extremely simple - a zero is supplied directly from the shield to the luminaire, and a phase is applied to one of the switch terminals. From the second terminal, the wire is fed to the output of the lighting fixture.

The implementation of this scheme is simple and fast. The number of terminals depends on the number of keys in the switch. On a single structure, there are only 2 terminals, and the socket must be equipped with two wires. It is simply impossible to get confused. It is required to start one wire under the terminal from the shield, and the second from the lighting device. Where and which one does not matter.

How to connect a switch with two buttons and backlight

The connection diagram for this electrical structure is not much different from the previous one. A three-core wire is brought out to the socket. Two wires are for a group of lighting fixtures, and one for power supply.This is where all the differences end.

In implementation, the method is a little more complicated, since you need to find a phase conductor and connect it to the required socket. The double switch is equipped with three connection contacts. The phase is most often displayed in brown or red, and from the lighting device the color of the wires can be the same. Before connection, the presence of phase voltage is checked, if necessary, the wire is marked.

How to turn off the LED in the switch

All actions for dismantling a neon or LED lamp are reduced to the technology of replacing a conventional switch. The algorithm of actions is as follows:

1. Completely de-energize the apartment, house, check the output voltage.
2. Remove the decorative keys with a flat screwdriver or by prying on both sides with your fingers.
3. The fastening bolts are unscrewed, the structure is removed from the mounting box.
4. With the help of an indicator screwdriver, the contacts of the conductors are rechecked for the absence of voltage.
5. When the connection diagram has been memorized, the wires are disconnected.

The disassembled design of the switch is carefully examined. It is equipped with latches that connect the two body parts. Once they are open, the breaker will split. One part and will be equipped with a resistor with an indicator light. The wires of the radio components are carefully cut from the backlight output and removed. The switch is assembled and installed in the reverse order.

How to get rid of "blinking" lamps and possible problems

The main problem that owners of switches with indicators face is the flickering of lamps and the indicator itself. Most of all, this phenomenon causes discomfort in bedrooms and an office. Improper use will adversely affect the operating time of the switch itself and the lamp. You can get rid of the problem in the following ways:

• Give preference to LED lamps that are compatible with the indicators in the switches. Such lighting fixtures are already equipped with a soft start and a resistor. The device is connected within a few seconds, so it does not flicker when the capacitor is discharged. The main disadvantage is the high cost of such lamps.
• Parallel connection of a shunt resistor will help to get rid of the problem. It does not directly affect the operating mode, but a small current will still flow through the resistor. Its power should be 2 W, and the resistance should be 50 kOhm.
  
• You can also connect an ordinary incandescent lamp with an energy-saving version. In this case, the current flowing through the indicator circuit will pass through the filament. The disadvantage of this method is the large amount of electricity consumed.
• Incorrect installation may be the cause of incorrect operation. For example, a mistake can cause the switch to cut off the zero, not the phase. This can cause not only incorrect operation, but also short circuits. To solve the problem, it is enough to correctly connect the switch or call the electricians.

The easiest, but not the most convenient way to get rid of the problem is to remove the backlight from the switch or install a conventional modification that is not equipped with bulbs.