Lighting under cabinets in the kitchen from LED strip: selection of elements, diagrams, do-it-yourself installation. How to repair an electric kettle yourself LED lighting circuit for a kettle

Scheme:

The case when, after a long wait, the switched on electric kettle still did not boil, led to the idea that it would be a good idea to provide visual monitoring of the serviceability of its heating element. The fact is that the built-in power indicator (for example, a neon lamp with a quenching resistor) is connected in parallel to the heating element and only shows the presence of 220 V voltage at its terminals. Even if the element is faulty, the indicator light will still shine to indicate that the kettle is on. As a result, a simple device was developed that solves the problem. Its diagram is shown in the figure above. The elements of the kettle (mains plug XP1, switch SA1 and heating element EK1) are outlined with a dot-dash line.

When the heater is working, the plug is inserted into the socket, but the switch is open, current flows through the circuit:
contact L of XP1 plug,
diode VD1,
resistor R1,
"green" LED crystal HL1,
resistors R2-R4, heater EK1,
contact N of XP1 plug.
The green glow of the LED indicates that the heater is working properly. The power consumed from the network in this mode does not exceed 3 W.

After closing the SA1 switch, the current through the “green” LED crystal stops, since its flow circuit is now shunted by the switch. The current flows: from contact N of the XP1 plug through the diode VD2, resistor R5, the “red” LED crystal HL1, resistors R2-R4 and the closed switch SA1 to contact L of the power plug. The green color of the LED changes to red. Through resistor R6 and diode VD3, capacitor C1 is charged, and the voltage from it is supplied to the power circuit of the music synthesizer DA1.

In the typical version of turning on the UMS series synthesizers (pin 13 is connected to the power supply plus, this is the most economical mode), the melody begins to sound immediately after the supply voltage is applied. But this is only the first of the melodies available in the memory of the microcircuit, and it is repeated until the power is turned off. By connecting pin 4 to the common wire, you can turn on the second melody in the list, but the synthesizer will also repeat it until the power is turned off.

If pin 13 is not connected to the power plus, to start playback it is necessary to apply a high-level pulse with a duration of 0.1...0.5 s to it. If the trigger pulse is too short, only a small fragment of the melody (five or six notes) will sound, but if it is long enough, it will be played in its entirety. Since pin 12 is connected to common, the synthesizer will turn off when the melody ends. You can read more about the work of musical synthesizers in the article by V. Drinevsky and T. Sirotkina “Musical synthesizers of the UMS series” (Radio, 1998, No. 10, pp. 85, 86).

The property of the synthesizer described above is used to musically confirm the connection of the kettle to a 220 V network and avoid listening to the same melody until the water boils in it and automatically turns off. The starting pulse forms the circuit R7R8C2. By selecting resistor R6, the supply voltage of the DA1 microcircuit is set to 1.5 V. Diode VD3 prevents the discharge of capacitor C1 through the power supply circuit of the LED HL1.

The alarm is mounted on the bottom cover of the kettle body in a hinged manner. Resistors R2-R4 are thermally insulated with asbestos fabric. The synthesizer chip is glued to the cover with the pins facing up. The remaining resistors, a VD3 diode, capacitors and a quartz resonator are soldered to them, like mounting posts. The HA1 piezo emitter is also glued to the cover; under it, several holes with a diameter of 1.2 mm are drilled into it for the passage of sound.

The HL1 LED is installed in place of the power indicator that was previously in the kettle. If such a design is not provided, it is most convenient to place the LED in the handle of the kettle so that its glow is clearly visible. It can be not only the type indicated in the diagram, but also another two-color one with common crystal cathodes, for example KIPD41A1-M. As a last resort, you can use two ordinary LEDs of different colors, connecting them according to the diagram. Having replaced the LEDs, you will have to clarify the values ​​of resistors R1 and R5, achieving sufficient brightness of the LEDs with minimal power consumption.

Instead of three two-watt resistors R2-R4, it is permissible to install one with a resistance of 7.5 kOhm and a power of at least 5 W, for example, wire PEV-5. It is better to take capacitors C1 and C2 imported with a permissible operating temperature of 105 ° C. The ZP-3 piezo emitter will successfully replace similar devices that can be found, for example, in “sounded” children’s toys. The KD105B diodes in the alarm device under consideration can be replaced by any other rectifiers with an allowable reverse voltage of at least 350 V.

Microcircuits of the UMS8, UMS9, UMS10 series are suitable as a DA1 music synthesizer. You should only take into account that the UMS8-06 and UMS10-56 synthesizers record one long sequence of musical fragments without pauses. The author used the UMS8-01 synthesizer, in which the melody of the song “Fire is beating in a cramped stove...” is recorded in second place.

Editor - A. Dolgiy

Household electrical appliances are widely used all over the world and one of the most common electrical appliances is the electric kettle. Despite the reliability of many models and manufacturers, the service life of electric kettles, like other electrical appliances, is limited, so kettles, sooner or later, break. And in this case, it is not necessary to send the kettle in for repair or purchase a new one - you can repair the electric kettle yourself. In this article, we will discuss with our readers how to repair the most common breakdowns in electric kettles.

Operating principle of an electric kettle

Before you take on the repair of any electrical appliance, you need to understand its operating principle - this rule also applies to the kettle. From the electrical diagram it is easy to understand the operating principle of this electrical appliance. Note that almost all models operate according to the operating principle below.

The principle of operation is as follows: after connecting the plug to the power source, the current passes through the wire to the contacts of the stand, on which all kettles are installed when heating water.

At the base of the kettle itself there are special contacts that are connected together with the contacts located on the stand - this way the circuit is closed and the heating element is heated. The electricity then passes through a thermal switch, a device that allows the kettle to turn off when it reaches a certain temperature (usually the boiling point). Also in the standard circuit there is a thermal protection switch, which is constantly on and is activated only if the user turns on an empty kettle. From the designated switches, electricity passes directly to the electric heating element (which is also called the heating element).

We have looked at the basic principle of operation of an electric kettle - now we will consider separately the operation of some of its circuits and sections.

Electrical diagram of components

Carefully examine the teapot stand and its contact point with the teapot itself. Inside the circular grooves you can find an electrical contact located on a small spring. It is through this contact that voltage from the general network is supplied to the electric kettle itself. In the center of the stand there is another contact, which, when in contact with the electric kettle, grounds its body. In fact, this contact does not play any role and is intended only to protect the user in the event of a violation of the insulation integrity.

The power cord that fits the electric kettle stand, inside this stand, branches into three wires, to which the terminals are connected. One wire is intended for grounding, the other two contacts go to concentric copper rings, which are used to transfer electricity from the stand to the electric kettle itself. Next, electricity from the copper rings goes directly to the heating element, which is installed at the base of the kettle body. As a result of the circuit closing, the water heats up.

overheat protection

Heating elements have high power and get very hot during operation, so each electric kettle is additionally equipped with a special protection system. The basis of the operation of this system is bimetallic plates, which, when heated to a certain temperature, unbend and open the circuit, thereby preventing further overheating of the kettle.

Automatic shutdown

Almost all modern electric kettles have a special system that disconnects the heating element from the voltage when the water reaches boiling temperature. The principle of operation of such a machine is simple - when heated, steam is supplied through a special channel to a bimetallic plate, which in turn is connected to a switch. When the kettle boils and the steam pressure increases, the bimetallic plate heats up and presses on the switch lever, thereby disconnecting the electric kettle from the network.

How to repair a kettle?

We have looked at the main technical features, and now we will look at how to repair an electric kettle. For the convenience of readers, we will consider specific examples that most often arise with kettles from various companies (Tefal, Philips, etc.):

1. The kettle stopped heating water. In this case, the malfunction is very minor - there is a break in a section on the heating element itself or there is no contact between some terminals and the terminals on the heating element. The connection is restored very easily - to do this, you need to disassemble the kettle and determine the location of the contacts. When determining where there is no contact, it is necessary to restore the connection of the terminal with the terminals on the heating element using pliers.
2. The kettle has stopped heating water and the indicator does not show that the kettle is on. First of all, we check the voltage in the network. If there is one, the reason is poor contact between the current collectors at the base of the electric kettle body and the stand. In this case, it is necessary to check how the spring-loaded contacts, which we discussed above, are holding. To do this, the stand is disassembled and a ring with a suitable contact is taken out. It is necessary to check how tightly they are fixed - as a rule, they become loose over time and you simply need to tighten them more tightly so that electricity passes through the contacts.
3. The switch or overheat protection does not work. When considering the question of how to repair an electric kettle, most often in practice they are faced with a non-working switch. It may be broken due to wear of plastic parts, rust on the surface of the bimetallic plate. To check the condition, it is necessary to remove the switch from the housing and check the integrity of the parts. After this, it is necessary to inspect the condition of the plates. If there is a strong deposit of steam or rust on them, it must be removed and the operation of the switch must be checked again. These measures are also taken if the overheating protection stops working (in other words, the kettle stops turning off) - it is necessary to check the condition of the bimetallic plates and, if necessary, clean them.
4. The kettle is leaking. In this case, it is necessary to check the integrity of the kettle body and see exactly where the leak is coming from. As a rule, if there is a strong leak, there may be no talk of repairing the kettle, especially if its body is made of low-quality plastic or the internal surface is severely damaged as a result of damage.

Electric kettles - thermoses, or thermopots, serve regularly for 2 - 3 years, then they usually fail. The main reasons for this are: they stop boiling water, they don’t pour boiling water and because of water leakage. There is a lot of material on the Internet about repairing thermopots, but there are almost no diagrams. The article briefly describes models of thermopots, the diagrams of which are copied from products whose malfunctions the author encountered during repairs. The article provides examples of circuit solutions used in most models of modern thermopots, despite the large number of clones produced by various companies.

In the above diagrams, the designations of most parts correspond to those indicated on the boards. For different models of thermopots, the secondary power supply circuits and control units are very different. All thermopots have a container for boiling water made of stainless steel. Thermal electric heaters, heating elements, usually two of them, are fixed in its lower part for boiling and heating water, in this case they are located in one block, which has three outputs. At the bottom of the container there is a thermal switch for a temperature of 88 - 96 degrees C or a temperature sensor, which gives a signal to turn off the heating element of the boiler when the desired water temperature is reached. On the side wall of the container there are mounted a thermal switch connected in series for a temperature of 102 - 110 degrees C and an FU fuse for 125 degrees C/10A, placed in a silicone tube. They turn off the power supply to the thermopot when the temperature of the boiling container increases due to lack of water or in the event of a short circuit. To supply hot water in thermopots, the same type of 12 V DC electric motors with a centrifugal pump are used.

Most of the thermopot parts are located on two boards. The control board, on which the control buttons and LEDs are located, is located in the upper part of the case. The main board, on which most of the power connectors, control units, relays, sources and secondary voltage stabilizers are located, is located in the lower part of the case under the boiling water container. Both boards are connected to each other by wire harnesses with connectors.

The diagram of the Elenberg TN-6030 thermopot is shown in Fig. 1. Earlier, in 2014, the author posted it on the go-radio website, so a link to this site is provided. The TN-6030 circuit is quite simple and completely analog. Constantly, a pulsating current flows through the water heating element EK1 and the diode VD9 in only one direction, so the resistance of this heating element is two times less than a similar heating element of the same power in other models, where it is powered by alternating current. When the electric motor is turned on, a constant pulsating current of a different polarity, up to 150 mA, begins to flow through it and the VD10 diode, and alternating current flows through the EK1 heating element. Automatic switching on and off of the heating element for boiling water EK2 is carried out by thermal switch SF1. Forced switching on of the heating element EK2 for up to 2 minutes is carried out by contacts K1.1 of relay K1. To transistors VT1 - VT2 of the control stage of relay K1, a constant voltage of 14 V, stabilized by the chain R3 and VD6, is supplied from the diode bridge VD1 - VD4. A common malfunction of this thermopot model is the burnout of the contacts of the thermal switch SF1, because all the current of the heating element EK2 passes through it. Replacing the thermal switch is not difficult; you just need to unscrew two screws on the flange and rearrange the two power connectors. Detailed videos of this replacement are available on the Internet.

Another malfunction is poor operation of the hot water supply pump. Its reason is an increase in friction on the rotor axis of an electric motor operating at elevated temperatures due to deterioration in the quality of the lubricant. The magnetic clutch of the pump consists of a magnetic disk mounted on the rotor shaft of the electric motor and a pump impeller mounted on the axle shaft in the cover of the pump housing. A magnetic disk is also fixed at the base of the impeller. A sealed gasket is installed between the two magnetic disks. Rice. 2.

The author lubricated the rotor support points at the ends of the electric motor housing with ordinary spindle oil. It helped for a couple of months. It is difficult to get to the front support point, I had to disassemble the pump and pour oil under the magnetic disk, and turn it with my finger, at this moment the electric motor is in a vertical position so that the oil flows into the right place. The remaining oil is poured over the edge. There is no need to remove the disk from the rotor axis; a couple of removals and it will not stay on the rotor axis. It’s easier to immediately replace the engine with the pump.

Water leaks in thermopots rarely occur, usually due to mechanical damage. One day, the cause of water appearing under the kettle turned out to be a barely noticeable crack in the upper part of the plastic case, under the lid, running along the rim of the container for boiling water. Steam penetrated into this crack, which then condensed on the inner surface of the case walls, and the plastic crumbled along the crack. That kettle was beyond repair.

The diagram of the Vitek VT-1188 thermopot is shown in Fig. 3. In this model, a secondary voltage of 12 - 14 V is supplied to the control units from transformer T1, installed at the bottom of the housing under the water tank, and from the rectifier bridge VD1 - VD4. A voltage of 5 V from the ic2 stabilizer is supplied to power the ic1 processor, which controls the entire operation of the thermopot. At the command of optocoupler ic3, processor ic1 should signal the activation of protection, SF1 or FU1, although it is not clear how - a buzzer is not installed in this model. At the bottom of the boiling tank there is an RT temperature sensor installed from two MF58 thermistors connected in parallel with a negative TKS in KD-3 housings. The boiler shutdown temperature is set manually using the sw2 button. Thermopots VT-1188 and VT-1187 do not have a heating element for heating water, which is why turning on and off the heating element for boiling, EK1 occurs more often than in other models. Therefore, in the VT-1188, the relay contacts burn out more often and the heating element burns out. The case of burnout of the relay mounting pin on the board is described in. If all these malfunctions occur, the kettle's display and pump motor work normally, but the water does not boil. If the relay contacts burn and stick, or transistor Q1 breaks down, the boiling mode may not turn off. When repairing these breakdowns, faulty parts are replaced.

Photo of the main board VT-1188. Rice. 4.

The VT-1191 thermopot diagram is shown in Fig. 5. The secondary voltage source for the control units is pulsed, made on the VIPer 12A microcircuit using a transformerless circuit. The constant voltage of 18 V at its output is filtered by capacitors EL3, C3 and inductor L2, then reduced by the zener diode ZD2 to 12 V. The control circuit operates on the ic1 processor, there are no markings on its body, there is only a label indicating the model of the thermopot. A voltage of 5 V is supplied to ic1 from the stabilizer on transistor Q4 and zener diode ZD3. The VT-1191 thermopot has two heating elements: EK1 for boiling and EK2 for heating water. Contacts K1,1 of relay K1 alternately connect the terminals of one of them to the network, depending on the voltage at pin No. 5 of ic1, which is supplied to the base of transistor Q1 through connector CN1, LED HL2 and R7. A small base current of transistor Q2 flows through thermal switch SF2, so SF2 is connected to the board and pin No. 4 of ic1 with a low-current connector. The electric motor is turned on by transistor Q3 when “+” appears at pin No. 3 of ic1. The malfunction of the thermopot was manifested in the fact that it did not boil or pour water, only the green HL3 indicator was on. The cause of the breakdown was the failure of the ic1 processor.

Fig.6 Photo of the main board VT-1191, fixed in the thermopot housing.

A lot of advice on repairing thermopots has already been given, but I’ll add two more:

1) Take photographs of the entire process of disassembling and repairing the kettle. This will then facilitate its subsequent assembly and especially the installation of power connectors. (Fig. 6).

2) If the housings of low-current connectors installed on boards wobble even slightly in their places, these housings must be glued to the board and the contacts must be soldered. Failure of connector contacts after repair and assembly of the thermopot can lead to new malfunctions.

Bibliography

• “Repair of electric kettle relay Vitek VT-1188”
• Radio magazine 2016-8-35.

Repairing an electric kettle is simple - anyone can do it. Inside there is a spiral rolled into the bottom that controls the thermostat and button. The design is powered by a voltage of 230 volts and is protected against overheating by a thermal fuse. More often they are wired - you have to change them. Cheap models lack the subtleties of protection.

Repairing an electric kettle with your own hands sometimes becomes an interesting task, especially if the lid and handle are cast and it is impossible to detach it from the electric kettle. Reason: The screws are under the edge of the door. You wonder how the Chinese managed to assemble a miracle of technology.

Repair of electric kettles in China

Products from Guangdong Province are widely known. China is rich in economic and other interesting zones that provide tax and some other benefits to manufacturers. The United States is not enthusiastic about the conflict with the heirs of communism, whose fate Nietzsche predicted a couple of centuries ago. Today we will look at how to repair a Chinese electric kettle, made according to a standard design for a company that does not seek to reveal the true origin, with a 95% probability of being a representative of Eastern Europe, perhaps, the Russian Federation. Let's see what our compatriots indulge in - the best examples of the world's household appliances pass through the hands of Guangdong workers.

China's GDP ranks second. Japan is third. Not bad, considering the state of the Land of the Rising Sun, which survived World War II. Feudal Japan became the world's largest electronics manufacturer.

Housing, side panel when repairing an electric kettle

Below are photos that allow you to personally enjoy the views of a detail of the simplest design. There will be links to the pictures in the text. If you want, look, if you don’t want, scroll blindly. Disassembly begins with the lid. If you skip this step, you cannot remove the side panel that hides the LED plus switch. With the side panel on it is more difficult to remove the bottom. Dilemma. Do the opposite, if you are looking for difficulties, then you don’t have to remove the lid at all!

Lid. It is held in place by two lugs and two pins. It’s a plastic monolith, you’ll be tortured to disassemble it, installation is even more difficult. The first photo shows the pins perfectly. There are two screws on the sides, immediately unscrew and remove the side panel. Everything is neat inside - plus models, we often find a whole mess of wires. Let's move on to the bottom.

There are three screws around the connector where the grounding terminal is provided (the structure hangs in the air). We unscrew it and make sure that the bottom is slow to come off. Along the perimeter there are six plastic teeth that fit into six holes in the housing. So that it does not accidentally fall apart, worn out by use, there is a guide on the sides of each tooth. One by one, you will have to snap off the teeth separately with a screwdriver (see photo below), if you break them, you will break the bottom when removing them. We took a picture of each tooth, illustrating what was said. We put the dismantled parts aside and look at the switch.

Switch, temperature sensor: the point of view of an electric kettle repairman

The photo shows from the bottom position. A shiny circle with a cut is a mechanical sensor. Thanks to the bimetallic plate, seizing the moment, the electric kettle turns off. The water boils and an increased amount of steam begins to be released. There is a small hole in the housing located under the switch, covered with a circular loose plastic plug (see photo). The plate is installed, located above the gate pair. Boiling begins and the temperature rises sharply. After a moment, you can hear a click. The tongue of the plate, made up of a pair of metals, bends sharply upward. Looks like a bimetallic relay.

Now the switch. Not so simple. The part has no visible connections, except for the metal bracket shown in the photo on the side. The upper movable part is attached to it. When we turn on the kettle, the tip of the switch rests on the tongue of the round plate with a cutout, and the bracket is compressed. Thanks to the design, the parts retain their initial position indefinitely. Click! The slightest tug releases the bracket, returning the switch to its original position.

Let's examine the bottom of the body. Here are:

• circular connector;
• rolled spiral;
• LED divider resistor rated 14 kOhm.

While the switch is dormant, the LED glows blue. Full voltage of 230 volts is applied. The photo clearly shows: the resistor was burnt, the contacts were inserted into the clamp terminals, one did not withstand inspection. I had to solder it. The divider resistor is connected in parallel with the rolled heater. The electric kettle turns on - the glow changes to orange. Dual LED (school teachers left out?), unlike typical use, both shades work simultaneously while the water is boiling. The addition of electromagnetic waves of different shades produces orange. It is difficult to list the shades that form the superposition (the repairman is deeply indifferent).

Remove the resistor, or it will burn out - nothing bad will happen. The LED will simply stop changing hue, tracking changes in the position of the switch. Color is not related to water temperature. It is easy to notice that there is no thermal fuse. We believe there is simply no protection. Those who wish can equip the part with a metal case, next to the ring connector. Provide protection against empty switching. This kettle may cause a fire if not protected. We recommend adding a thermal fuse to the device. Place it not somewhere in the center, but around the perimeter of the heating element, increasing reliability.

The resistance of the heating element is 30 Ohms. The photo shows through fractions the power values ​​on a metal surface of 220 and 240 V. Enough to understand what can break. The design of the electric kettle is simple, even a kettle can be repaired, but... It was easy to remove the lid and put it back! We hope that readers will solve the question on their own; we find it difficult to answer. But we will show you how to disassemble the switch for those who want to clean the contacts. The gap distance is tiny, steam is in the air. Just look at the two screws from the photo: they are covered with rust, although the electric kettle has not been properly used.

We believe that six months later you will need to refresh your contacts. Let's look at the switch:

1. Place your finger on the plastic ear that secures the switch to the body.
2. Use your thumb to press the button on the opposite side.
3. Squeeze your fingers gently and the retaining bracket will fly out. Protect it more than the apple of your eye, otherwise the electric kettle will only have to be thrown away.

Assembly is carried out in reverse order. Hook the bracket with the front part of the button, press it against the base, and carefully place the part in place without any extra effort. The bimetallic plate can be easily removed with a knife or screwdriver. Self-repair of electric kettles consists of such little things, otherwise it won’t take long to break the lid while putting it on! The contacts are made of bronze, visible in the photo. You cannot clean it with alcohol or gasoline, there is plastic nearby. We think we'll have to get hold of acetic acid; the switch is waiting in line.

You will have to disconnect the terminals. The Saturn model in question is not a simple one. The photo shows a small hole in the terminal to which the spike of the second half corresponds. If you press there with an awl, the connection can be disassembled without any problems. Otherwise... It’s impossible to separate one from the other. The process is aggravated: the joints are protected by heat-shrinkable cambric, which is poorly heated with a hairdryer. It crumbles easily, barely holds on, but... does not come off. Therefore, if necessary, cut and disassemble the assembly. The clamp terminals are disposable. The resistor wire jumped out, it was not possible to crimp it back, it was not convenient. I had to solder it.

Weld plastic with a soldering iron. Along the way, using the necessary additives (polyethylene). Choose a material that is compatible with the food industry. Use heat-resistant glue that is harmless to humans.

Conclusion on electric kettle repair

As readers understand, this is one of the cheap models of Chinese teapots, made to order from a certain company. The maintainability of the product is zero. Difficult to disassemble, even more difficult to assemble. By picking, it is easy to spoil the presentation and functionality. The bottom got dressed quite simply, with considerable effort and threatening clicks. The lid caused a lot of trouble. Skillful use of a hairdryer will help. With only a screwdriver, disassembly will be difficult.

We recommend evaluating the assembly in the store. How difficult will it be to disassemble the device in order to repair the electric kettle with your own hands? If the product is disposable, this is not very encouraging, and if, in addition, it is dangerous... no comment.

We hope that after such a detailed review, readers will be able to repair Tefal electric kettles and repair Scarlet electric kettles. After all, most products are made in China. We want to say goodbye, look at the pictures, evaluate, study. If the bimetallic strip is inserted the wrong way, the electric kettle will stop turning off when it boils! Although the click is heard.

Main surprise

Boiled water causes allergic reactions. It is difficult to name the percentage of people susceptible to the disease. Kashpirovsky considers half of the planet to have an aggravated reaction. Treats almost 100% of those who apply. Some (the impudent ones) are sent back. Let local hospitals try it out.

The regulation of the immune system is poorly understood by science. A sane person who has experienced angioedema will be careful not to reject the slightest possibility of cure.

LED lighting under cabinets in the kitchen is ergonomic, beautiful and modern. In the article we will talk about how to choose the right system elements, what connection schemes are available, how to install the tape as an independent element and in a special box (profile).

Choosing an LED strip for lighting under cabinets is an interesting, effective and not too complicated solution for the home craftsman. Such additional lighting undoubtedly also fulfills aesthetic purposes - it highlights individual functional areas, accentuates decorative elements with color, and sets a fashionable, modern tone for the kitchen design.

Selecting LED strip

An important characteristic of LED strips for installation under cabinets in the kitchen is resistance to water vapor. Insufficient moisture protection can lead to a short circuit, and, therefore, to the risk of fire. When purchasing a tape, you need to pay attention to the degree of protection of the shell, which is marked with a two-digit number after the Latin letters IP. The first number indicates protection from dust and dirt, and mechanical damage. The second number is protection against moisture. The security of a device or device is assessed on a scale from 0 to 9 for both parameters.

In terms of tightness (moisture and dust resistance), LED lamps and strips can be marked:

• IP33 - open type of conductor, not recommended for kitchens;
• IP65 - one-sided sealing of the side on which electronic elements are located, allowed for installation in a humid kitchen environment;
• IP67, IP68 - double-sided, completely sealed tape - recommended for installation in the kitchen.

If the selected lamp or strip with LEDs has insufficient security, it is necessary to use a protective shade or special profiles to collectively ensure the proper level of security.

In order for the LED strip to provide enough light, it is important to choose the right power density, which is characterized by the number of LEDs per linear meter. Each type of strip can have a different number of LEDs. This can be determined both visually and by reading the characteristics of the product.

For decorative purposes, 30 or 60 LEDs per meter are usually sufficient. To fully illuminate the work surface, it is better to choose a strip with 120 or 240 diodes.

When calculating the illumination, you need to take into account the power consumed by the tape, remembering that compared to incandescent lamps, the luminous flux of LEDs is approximately 5 times higher.

Table. Belt power calculation

The numbers in the strip markings indicate the size of one LED:

• SMD-3528 - diodes measuring 3.5x2.8 mm;
• SMD-5050 - diodes measuring 5.0x5.0 mm.

For monochrome strips with the specified characteristics, the luminous flux, measured in lumens and which is another characteristic of LEDs, will be maximum. For polychrome RGB tapes, the color of which is set depending on the settings of the regulator or control controller, the total number of crystals in each diode corresponds to a combination of basic colors that do not turn on simultaneously. Consequently, when only part of the crystals that produce a certain color are working, the luminous flux will be lower.

The colors of monochrome diodes with their own crystal glow are:

• red;
• orange;
• yellow;
• green;
• blue;
• violet.

The color of monochrome diodes is characterized by a narrow spectrum of emission, which should be taken into account when choosing a backlight. The color of objects and, most importantly, products is significantly distorted; they may not look the same as under natural light or illuminated by fluorescent lamps.

The white monochrome LED is an ultraviolet-emitting semiconductor coated with a phosphor. The principle of operation is similar to fluorescent lamps that are familiar to most. The shade can also be from “warm” to “cold” and is indicated in the form of the corresponding glow temperature, measured in Kelvin as in conventional LED lamps.

The color of the surface of the printed circuit board on which the LEDs are located is usually white, but you can choose other colors: brown, yellow, black, which will look better on furniture when installed openly. For ease of installation, the tape is equipped with adhesive tape on the reverse side.

Selecting a power supply and additional devices

You cannot plug the LED strip into a household outlet - it will burn out immediately. It is designed to operate at direct current with a voltage of 24 or 12 V, obtained through an appropriate pulse converter (power supply). The power of the device must correspond to the total power consumption of all connected tapes. For example, you need to connect three 5 m SMD-5050 reels with a power of 7.2 W/linear. m. The total capacity is:

5 m 7.2 W/linear m = 36 W

The power supply is selected with a margin of 20%, therefore, you will need a device with a power of at least 45 W.

The design of the block can be different:

1. Sealed, compact unit in a plastic case.
2. Sealed power supply in an aluminum case. Expensive, climate-resistant, often used in outdoor, street lighting.
3. Open block in a perforated housing. The largest, inexpensive, requires additional protection from direct moisture. There are powerful models - one block is enough for all the illumination.
4. Network power supply. Low power, up to 60 W, does not require installation. Multiple tapes will require separate power supplies.

The kitchen power supply must be moisture-resistant or installed in a place protected from moisture. It is desirable that the driver contains protection against voltage surges, which extends the life of the LEDs.

It is not recommended to connect LED strips in series, otherwise wear will be high and luminosity will be uneven. When connecting several tapes, it is correct to use an amplifier that provides uniform current supply to different sections of the electrical circuit.

If desired, the backlight can be connected via a dimmer - a device that smoothly reduces the power and luminosity of lighting fixtures. This way you can maintain the backlight in the “work” and “rest” modes.

To control the LED strip, PWM controllers are used that can provide the correct shape of the pulsating current to adjust the brightness of the LEDs

Amplifiers and dimmers are matched to the lighting system based on current strength.

LED backlight connection diagrams

Basic rules for connecting lighting elements into a circuit and installation:

• observe polarity;
• power it through a power supply with a voltage of 12 or 24 V in accordance with the type of tape and marking, placing it as close as possible to the tape (maximum distance - 10 m);
• The tape should not be sharply bent or twisted. It is better to cut and make the corner by soldering (with care, then insulating the conductive paths with heat-shrink tubing) or with a special connector. Soldering, according to craftsmen, ensures contact without electrical losses;
• the fewer connections and the thicker the wire cross-section, the less electrical current loss;
• It is better to mount a high-power tape in a profile (box);
• pieces of tape longer than 5 m should only be connected in parallel;
• Place the power supply in a ventilated place, protecting it from overheating.

The places where the LED strip can be cut are usually shown on the product itself.

Below are the basic connection diagrams for monochrome and RGB strips.

Direct connection diagram for LED strip. Several tapes are connected in parallel to one current source

Connecting an LED strip using a dimmer to adjust brightness

Several LED strips, switched on using a dimmer or PWM controller, must be connected using an amplifier

Connection diagram for RGB LED strips

RGB strips are connected to the controller with four wires, three of which are responsible for one of the colors, the fourth is common. Marking: R - red, G - green, B - blue. The “V-plus” wire is common. The easiest way to connect is using a connector, but you can also carefully solder it. To independently connect the controller and amplifier, two power supplies are sometimes used in the connection diagram.

Tools and materials for installing LED strips

To install the LED strip under kitchen cabinets yourself, you will need:

• connection of elements can be done in various ways, and you will need: a soldering iron, solder, rosin and heat-shrinkable tubing, or wire lugs and crimp for lugs, or connectors;
• scissors;
• insulating tape, double-sided tape, fasteners;
• a tool for cutting holes in furniture for laying wires, for example a jigsaw;
• selected LED strips;
• power supply and other elements of the electrical circuit, if necessary - dimmer, amplifiers, controller;
• box (profile) - when performing the appropriate installation;
• cable.

It is important to understand that LEDs still produce heat when they glow. It is directed into the substrate, the base of the diode. To prevent overheating of semiconductors, which significantly reduces their service life, it is advisable to glue the tape to a special aluminum profile or substrate with high thermal conductivity.

Selection of cable cross-section

As a rule, to install lighting in the kitchen, a cable with a cross section of 0.5-2.5 mm 2 is used.

• I - current, I = P/U or I = U/R (P - power, U - voltage, R - resistance);
• ρ - resistivity, for copper cable ρ = 0.0175 Ohm mm 2 /m;
• L—cable length;
• ΔU is the maximum permissible voltage drop between the power supply (PSU) and the load (tapes), ΔU = U PSU -UΣ tapes, if the voltage of the PSU is 12 V and the tapes are 12 V, then ΔU is taken to be 5-10%, i.e. 0.6-1.2 V.

The cross-section of the cable also depends on the length of the wiring; the longer the wire, the less power will be supplied to the light source, as can be seen from the following table:

Installation of LED strip under kitchen cabinets

The basis of a well-executed installation is thoughtful planning - how to choose where and what elements of the circuit to place.

The LED produces a directed beam of light, most often it is a 120° sector strictly along the central axis of the semiconductor. Less common options are 90°, 60° and 30°. By attaching the tape to the bottom of the hanging cabinet and moving away from the wall, a very clear stripe is formed on the vertical surface, moreover, wavy between light and shadow, which can have a detrimental effect on the overall picture.

It is necessary to distribute the light source so that the dividing strip of light and shadow from the backlight falls on a natural boundary, for example, between the edging of the working surface and the wall cladding. In the simplest case, the tape is mounted close to the wall to illuminate it completely. By choosing different options, you can work with the visual “depth” of the working surface to the benefit of the overall design.

Strips with diodes that have a narrow sector of illumination can be mounted at the very edge under the cabinet so that the wall is not illuminated at all. A universal way to distribute light is to use aluminum profiles with light-diffusing protective films. Even with the height of the profile sides, if desired, you can form the required shape of the illumination spot.

The installation itself, with some skill in working with the tool, is not very difficult.

1. We pass the cable to the connection point as inconspicuously as possible by drilling a small diameter hole on the back of the cabinet.
2. A low-power LED strip can be attached directly to the prepared and grease-free surface of the bottom of kitchen cabinets. Tapes of measured length, having an adhesive layer, are simply applied to the selected location and pressed, removing the protective film immediately before installation. If there is no such layer, you will need double-sided tape. To disguise the tape, you can protect it with a profile to match the cabinet.
3. We fix the power supply, make electrical wiring, carefully securing the wires using clips or double-sided tape.
4. We connect all the elements into a circuit, be sure to check the wiring with a tester for a short circuit between the supply wires, and only then connect it to the network. The backlight is ready.

If, due to increased power or for aesthetic reasons, you plan to install the strip in a profile, then first it is easier to lay the LED strip in the profile and connect the power pins. After this, the profile is secured to the cabinets using double-sided tape. You will have to change the sequence only if the profile is attached using self-tapping screws screwed in from its inside side.

In the next video, the same master as in the previous video gives advice on installing the tape in the box.