Why does an LED light glow when turned off? Why LED and energy-saving lamps may glow after being turned off. Main reasons and their solution

If you are faced with the problem that the LED lamp is on when the switch is off, do not be surprised. This indicates that current is flowing through the LEDs. The brightness of the glow depends only on its strength.

On the one hand, this phenomenon has a positive side, if the lighting is in the toilet or corridor it can be used as night lighting. What if it’s in the bedroom? It is possible that the light does not smolder, but flashes periodically.

There may be several reasons for this phenomenon:

• Use of illuminated switches;
• electrical wiring faults;
• features of the power supply scheme.

The most common reason for a lamp to glow after being turned off is backlit switches.

Inside such a switch there is an LED with a current-limiting resistor. The LED lamp glows dimly when the light is turned off, because even when the main contact is turned off, voltage continues to flow through them.

Why does an LED lamp burn at full heat and not at full power?? Thanks to the limiting resistor, the current flowing through the electrical circuit is extremely insignificant and insufficient to light an incandescent electric lamp or ignite fluorescent lamps.

The power consumption of LEDs is tens of times lower than the same parameters of an ordinary incandescent lamp. But even a small current flowing through the backlight diode is sufficient for the LEDs in the lamp to glow weakly.

There can be two lighting options. Either the LED lamp lights up continuously after turning off, which means that sufficient current flows through the LED backlight of the switch, or the light flashes periodically. This usually happens if the current flowing through the circuit is too small to cause a constant glow, but it recharges the smoothing capacitor in the power supply circuit.

When sufficient voltage gradually accumulates on the capacitor, the stabilizer chip is triggered and the lamp flashes for a moment. Such blinking must be definitely combated, no matter where the lamp is located.

In this operating mode, the lifespan of the power board components will be significantly reduced, since even the microcircuit does not have an infinite number of operation cycles.

There are several ways to eliminate the situation when the LED light is on when the switch is off.

The simplest is to remove it from the backlight switch. To do this, we disassemble the housing and unscrew or bite off with wire cutters the wire going to the resistor and LED. You can replace the switch with another one, but without such a useful function.

Another option would be to solder a shunt resistor in parallel with the lamp. According to the parameters, it should be designed for 2-4 W and have a resistance of no more than 50 kOhm. Then the current will flow through it, and not through the power driver of the lamp itself.

You can purchase such a resistor at any radio store. Installing the resistor is not difficult. It is enough to remove the lampshade and fix the resistance legs in the terminal block for connecting the network wires.

If you are not particularly friendly with electricians and are afraid to “interfere” with the wiring yourself, another way to “fight” backlit switches can be to install a regular incandescent lamp in the chandelier. When turned off, its spiral will act as a shunt resistor. But this method is only possible if the chandelier has several sockets.

Problems with electrical wiring

Why does the LED lamp glow after being turned off even if the backlit button is not used?

Perhaps, when installing the electrical wiring, an error was initially made and zero is supplied to the switch instead of a phase, then after the switch is turned off, the wiring still remains “under phase”.

This current situation must be eliminated immediately, since even with a scheduled replacement of the lamp, you can receive a sensitive electric shock. Any minimal contact with ground in this situation will cause the LEDs to glow dimly.

Features of the power supply

To increase the brightness of the glow and minimize lighting ripple, high-capacity capacitors can be installed in the power driver circuit. Even when the power is turned off, there is enough charge left in it to light up the LEDs, but it only lasts for just a few seconds.

LED lamps are increasingly being installed instead of conventional “Ilyich bulbs”. Their advantages are undeniable. And very often problems arise with these light bulbs - they glow weakly, “smolder” or flicker when the switch is off. In this review, we will look at the causes and ways to eliminate such defects, but most importantly, we will try to reproduce this phenomenon specifically. After all, a weak glow, without flickering, can be very effective in some cases, it would be a sin not to take advantage of this and turn a bug into a feature.

Why does the lamp glow or blink?

The situation when the switch breaks zero is ubiquitous in Soviet-era wiring. This phenomenon is so common that sometimes it seems as if it was done on purpose. Let me remind you that in the “correct” electrical wiring, the switch must break the phase. A broken zero, by the way, causes the indicator screwdriver attached to it to light up. Similar to an indicator screwdriver, a light bulb sometimes only needs a fraction of a milliamp to produce a faint glow.

Why do some lamps glow dimly and others flicker? This is usually due to the design of the lamp driver, which is hidden in the base. It is believed that a flashing lamp has a higher quality driver, while a smoldering lamp has a cheaper driver. It’s difficult to say about reliability here; both burn out.

How to eliminate smoldering/blinking

Regardless of the cause, this phenomenon is quite easily eliminated. To do this, you should connect a capacitor in parallel with the lamp; it is more convenient to do this on the terminal block of the chandelier. When using backlit switches, a capacitor capacity of about 0.1 µF is needed, in other cases 0.047 µF is sufficient. In all cases, the voltage for which the capacitor is designed must be at least 400 V, and for greater reliability it is better to set it to 600 V.

On the Internet, some recommend using a 100 kOhm resistor instead of a capacitor with a power of at least 1 W. I didn’t have to try it, but I think it’s also a suitable option. However, it is still better to install a capacitor - unlike a resistor, it does not dissipate useless power and there is no heating at all.

Using the glow for good

Let me make a reservation right away: only “smoldering” lamps will do; it’s unlikely that it will work with blinking ones. I personally witnessed the long operation of lamps in this mode, but I do not rule out that these experiments can significantly shorten the life of the lamps. There are too many different lamp designs and not enough data to make clear conclusions.

So, a weak glow can be used as a feature, an additional lighting option. A night light in the corridor, a romantic twilight in the room - “smoldering” can be used effectively. The main thing is to learn how to properly control this glow.

A good result will be achieved by proper “correct” wiring and switches without backlights. That is, when the lamp is turned off, it does not glow at all.

The same capacitor, but connected in parallel with the switch, can make it glow. Also, capacitors of 0.047-0.1 µF for 400-600 volts are suitable. Here you may have to select a container for the desired glow. For convenience, you can use a two-key switch instead of a single-key switch: the first key must be connected according to the standard circuit, and the second through a selected capacitor. You will get two modes - normal and night light!

If the lamp glows initially, you can try connecting a capacitor in parallel with the lamp to eliminate it, and another capacitor, but of a larger capacity, to the second switch key. In general, you will have to experiment. But overall, I think this idea is quite interesting.

In all my experiments with the "night light" I used not dimmable lamps. The photo below shows two types of cheap lamps that “smolder”.

Does the meter shake due to the "smoldering" of LED lamps?

The current consumption when the lamp “smolders” is several milliamps; as a rule, meters do not respond to such currents. But in principle this is not important: energy consumption is so negligible that it is not noticeable against the background of the overall energy consumption of a house or apartment. Theoretically, to consume 1 kWh, the lamp will have to smolder for several months.

This concludes the essay, good luck with your experiments with lamps.

One of the most common problems associated with LED bulbs is that the LED bulb glows when the switch is off. There are several reasons for the appearance of such a glow, ranging from the peculiarities of the functioning of a particular device to the poor quality of the device. To accurately determine the reason for the light bulb to work after turning off, you need to become more familiar with how it works. This will allow us to understand where the failure occurred.

LED light bulbs are very popular and in demand; they are gradually replacing similar devices with incandescent filament from the market. Despite the significant cost, many apartment owners strive to purchase diode lamps, since they have a significantly longer service life, efficiency and reliability.

Compared to incandescent lamps, the design of diode devices is somewhat more complex. Let us highlight the main elements and describe their purpose:

• The base is made of brass and plated with nickel, which prevents corrosion and promotes reliable contact with the cartridge.
• The polymer base of the base part is coated with polyethylene terephthalate to protect the device body from electric shock.
• Driver – is implemented according to the circuit of a galvanically isolated modulator of an electric current stabilizer. The main purpose of the driver is to ensure stable, uninterrupted operation even during network voltage fluctuations.
• Radiator – made of anodized aluminum alloy. Required for effective removal of thermal energy from the remaining elements of the light bulb.
• A printed circuit board made of aluminum on a heat-conducting mass guarantees the required operating temperature of the chips by removing heat to the radiator directly from the chips.
• Chips - in fact, this is the lighting mechanism, in other words - diodes.
• The diffuser is a glass hemisphere, the level of light dispersion of which tends to the maximum.

LED lamp device

The principle of operation for the common man is quite complex and confusing. In short, glow occurs as a result of the release of photons due to the constant change and recombination of electrons, followed by a transition to other energy layers. The uninterrupted flow of the process is ensured by the semiconductor materials of the chips. To ensure optimal operating conditions for the entire device, various resistors or current-limiting mechanisms are used.

Some manufacturers today are trying to introduce improved technologies for creating a glow, in particular, using special diode bridges. The cost of such light bulbs is slightly higher compared to other LEDs, but the quality fully corresponds to the price.

Despite the excellent consumer properties and reliability, sometimes consumers complain about certain problems. So, very often there is a dim glow, even if the lights in the room are completely turned off. Naturally, this phenomenon has a negative impact on efficiency, because energy for the glow is still consumed. In addition, it interferes with sleep. The lamp may emit dim light from a few minutes to several hours. So you should definitely sort out the problem so as not to overpay extra money.

It is very common to experience a dim glow even if the lights in the room are completely turned off.

There are several main reasons explaining why LED lamps light up when the switch is off:

• Problems related to electrical wiring in the apartment. For example, on one of the sections of the electrical circuit there is poor-quality insulation.
• The lighting device is connected to a switch equipped with a backlight.
• The light bulb uses low quality emitters as a light source.
• Functional features of LED devices.

The biggest problems arise when the cause is poor-quality insulation. Therefore, first you need to work out and discard all other possible causes of this phenomenon. If it is necessary to check the insulation, then this is done as follows. A high voltage is applied for a minute, that is, conditions conducive to the occurrence of breakdowns in the electrical circuit are simulated. If the problem really is isolation, it will be difficult to correct the situation. This is very labor-intensive, because you will have to destroy the wall and peel off the wallpaper, since the wiring is usually installed using. Once you've replaced the insulation, you'll need to shingle it, caulk the wall, and return the wallpaper to its original location.

Fortunately for homeowners, problems with poorly executed insulation are relatively rare. Much more often, the reason why an LED lamp glows after being turned off is the connection of light sources to a switch equipped with a backlight. In this case, the lighting mechanism located directly in the switch closes the electrical circuit. As a result, current passes, albeit in very small quantities. However, this is more than enough so that after switching off the LED lamps continue to dimly illuminate the room.

When purchasing cheap lighting fixtures, be prepared for the fact that there may be significantly more problems with them than when purchasing high-quality LED lamps. The low quality of the finished product very often affects the presence of errors in chips and boards. Therefore, you should not save much, because by paying a little more money, you will get a high-quality device that will work reliably and without interruption for a very long time, saving energy.

In some cases, the reason why LED lamps glow when the lights are off is the functional features of the device itself. Even the most expensive and high-quality lamps can sometimes behave this way. A variety of processes occur in resistors, for example, when electric current is supplied, a small accumulation of thermal energy occurs in the resistor itself. And even when the light in the room is turned off, due to the accumulated energy, the glow is maintained in the light bulb. Typically, this phenomenon occurs over a very short period of time. In addition, manufacturers try to make resistors from special materials that prevent the accumulation of excess thermal energy.

Having decided why the LED light is on when the light is off, you can move on to solving the problem. The following is a list of basic recommendations, depending on the causes of this phenomenon. If dim light is associated with purchasing a product at an affordable price, but of low quality, then the advice here is very simple - you need to go to the nearest store and buy a high-quality light bulb from a reliable manufacturer.

If the problem is the backlight in the switch, there may be several solutions. You can act logically and, following the example of the first point, go to the store for a switching device that does not have backlighting. Another option is to cut off the power wire that controls the backlight. To do this, you will need to open the switch, which is done quite simply and quickly; even beginners in this matter will be able to disassemble and reassemble the device on their own in a few minutes. If you cannot do without backlighting, then you can just install another resistor in the circuit, which will prevent the accumulation of energy.

The main thing is to find the cause of this glow, after which you can begin to take action.

Isolation, as noted earlier, causes the greatest difficulties in solving the problem. If you do not want to violate the integrity of the wall, then you can try to go the other way. Its essence is to connect an additional load (relay, resistor, incandescent lamp) in parallel with diodes that do not stop burning. The only condition is that the resistance of the connected additional device must be less than that of the LED lamp. Due to the weak resistance, the connected element will not light up, and due to the redirection of current, the LED lamps will also not light up after turning off.

So, we told you why LED bulbs light up when the switch is off, and also that solving such a problem is not so difficult. The main thing is to find the cause of this glow, after which you can begin to take action.

Recommendations for choosing LED lamps - how not to make mistakes when purchasing

To avoid problems with LED lamps during operation, we recommend purchasing products from trusted and reliable manufacturers. You always have to pay for quality, so such light bulbs can be very expensive. However, with high-quality products, you will be able to avoid many problems in the future, including those where the LED light stays on when the switch is off. Be sure to read the instructions included in the product packaging. They indicate how to use LED lamps correctly, as well as what is not recommended to do.

As a rule, it is reported that the use of certain devices is highly undesirable for high-quality lighting of the lamp. For example, various timers, brightness controls, photocells, and backlit key switches can cause malfunctions. To achieve the greatest effect when lighting, it is necessary to take into account the compliance of the lamp indicators with the conditions where it will operate. You should buy those models that suit you based on the luminous angle, color rendering index, light temperature, luminous flux, and, of course, lamp power.

Pay attention to the radiator, or more precisely, its size. It is designed to quickly and effectively remove thermal energy released during lighting directly from the light sources themselves. Be sure to check the correspondence between the lamp power and the dimensions of the radiator. If the power is high, while the cooler is not large in size, we do not recommend buying a lighting device of this model, since problems may appear in the future, including the LED may light up after turning off. The instructions usually indicate what material the radiator is made of. Preference should be given to aluminum, ceramics or graphite.

Another important point is the joint between the lamp body and the base. You should check for nicks or other mechanical defects along the edge of the holder. The base must be tightly and securely attached to the body, without any play.

The next stage of checking the quality of the light bulb is to determine the pulsation level. The glow should be constant and uniform, without blinking or shaking. Due to the fact that the pulsations are invisible to the naked eye, we turn to the help of a mobile phone or camera. By filming a switched-on LED lamp with a video camera, we will be able to see the blinking, if, of course, it occurs. Manufacturers of high-quality lighting devices have a minimal level of pulsation; even through a phone camera it is difficult to see it.

At the very beginning of the 21st century, fluorescent or, as they are also called, energy-saving lamps in a compact arc-shaped or spiral design appeared on store shelves in our country. Some acquired these lamps a little earlier, having the opportunity to be on business trips abroad or vacations in European countries, some a little later. But everyone who purchased them bought them for one single purpose - to save on electricity. And this really worked out and bills came in for noticeably smaller amounts, accordingly the demand for these lamps grew and over time the assortment expanded to satisfy the most demanding consumer, but...

Technologies do not stand still and as one technology develops, another begins to develop, and sometimes it happens that these technologies come into conflict with each other.

With the development of energy-saving lamps, the range of switches has also developed; now there are quite a lot of them. These include one, two or three keypads, backlit, dimmer switches, pass-through switches and the like.

In our case, we will talk about backlit switches, because... They are very widespread and in many apartments they are already installed or are planned to be installed.

When installing a backlit switch, you need to keep in mind that installed LED or fluorescent lamps that will be powered by this switch will conflict with it. This conflict is expressed by the fact that when the switch is turned off, the lamp will light or, in the case of fluorescent lamps, blink, Therefore, you need to make a decision about whether you really need an illuminated switch or not. Just a couple of years ago, most electricians did not even know about this problem.

This happens because when the switch is in the off position, the electrical circuit does not completely open due to the backlight powered through a resistance. Since the circuit is not open, a small voltage is supplied to the lamp, and this voltage is enough to light the lamp at about 5% power. That is, when turned off, the lamp will operate in night light mode. In cases with fluorescent lamps, the lamp flickers subtly at different frequencies. Here the situation is such that the capacitors that are installed in the lamp soft starter accumulate the energy coming from the open switch and, when the full capacity is reached, this energy splashes out, which visually looks like blinking. In both cases, the service life of the lamp is not reduced. There are also times when everything works perfectly and nothing lights up or blinks anywhere. And it happens that, for example, everything works fine for a year, and then it starts to flash and light up. It all depends on the resistance in the switch and in the internal component of the lamp.

Ways to solve the problem

If you have already installed backlit switches and bought expensive LED lamps and were disappointed in advance that they could have sold you a defective product, know that this is not the case. The problem can be solved in several ways, which our specialists have tested in practice:

If you have a multi-arm chandelier, then you can remove the blinking or backlighting effect by installing the lowest-power incandescent lamp in one of the arms. It will collect all the current passed through the backlight. This can also be applied if you have ceiling lights installed. Even if you have one horn for one lamp in the room, the problem can be solved with the help of an adapter from one socket to two;

Directly in the switch, use wire cutters to cut through the resistance of the power supply to the switch illumination. That is, turn a backlit switch into a switch without backlight. Of course, this method can be used only by de-energizing everything in advance;

Replace the resistance in the switch with a resistance with a higher ohm. In this case, detailed consultation with an electrician and, accordingly, his participation in the replacement are required.

So if you bought LED lamps, and they glow when turned off, know that the solution to this problem is not so difficult and, in the first two cases, not very expensive.

There is such a thing as a slight glow of a diode lamp after the power has been turned off. There are several explanations for this, some factors relate to electrical safety, and some relate to the functioning of a light source of this type.

In any case, to understand why an LED light bulb lights up when there is no load, it is necessary to consider the operating conditions of the lighting device and determine the cause in each specific situation.

Device Features

The design of this type of lamp is more complex than its analogue with an incandescent filament. Main elements: base (screw, pin), board with emitters, diffuser, driver. The principle of operation is based on the recombination of electrons and holes with transfer to another energy level, resulting in a glow that is a consequence of the release of photons. These processes are facilitated by the use of certain LED semiconductor materials.

To ensure acceptable lamp operating conditions, a current-limiting element is used. In simpler circuits, a resistor is used for this purpose.

Diode lamp circuit

Higher quality light sources operate on a different principle: the circuit is based on a diode bridge, which rectifies the mains voltage and supplies it to LEDs connected in series.

Lamp glow when the load is off

There are several likely factors that could explain why the lighting element is still lit after being disconnected from the power source, albeit dimly:

1. Problems with electrical wiring, in particular, poor-quality insulation on one of the sections of the circuit.
2. The LED lamp is connected to a backlit switch.
3. Poor quality emitters used in the design of the light source.
4. Functional features of the lamp.

If the emitters burn when the switching device is in the off position, it is recommended to first consider all other factors except the first, since it is problematic to determine the area of ​​hidden wiring that is weak in insulation.

To do this, conditions are created under which a circuit breakdown occurs (high voltage is applied for 1 minute). The problem area, due to which the diode lamps glow after the load is turned off, will have to be opened: the integrity of the wall is compromised if the wiring is laid using the gating method.

A very common situation occurs when energy-saving light sources function differently when connected to a backlit switching device. The problem here lies in the fact that the lighting element installed in the switch completes the circuit, which means it passes a small current. It powers the diode lamps when the lights are off.

The problem of cheap LED products is no less common. If a product of low quality at an affordable price was chosen, and usually the connection between these factors is direct, then there is a high probability of an error in the soldering board. But it happens that the emitter, although dimly, burns due to the functional features of the design.

In particular, we are talking about the processes that occur in the resistor when a load is applied to the lamp: this element accumulates energy as current flows through the circuit, and after the load is turned off, it maintains the glow in the emitters.

How to solve the problem of dim light

1. If you initially purchased a cheap LED lamp, then it is possible to eliminate the glow only by installing a product from a reliable manufacturer and of high quality.
2. When the problem lies in the backlit switch, it can be eliminated in different ways. The simplest solution is to change the switching device to a model without backlight. You can also cut off the corresponding backlight power wire; this is done after opening the switch. But in some cases it is important to preserve this function. Then you need to install a resistor in parallel on the desired section of the circuit.
3. The hardest problem to fix is ​​the one in the wiring. To do everything correctly, of course, it is recommended to find the source of the leakage current. But, as already mentioned, this will entail other difficulties. But as a result, when the light is turned off, the diode lamps will not light up. But you can go another way, a simpler one. To do this, a load (incandescent lamp, resistor or relay) is connected in parallel with the diodes that light up. It is important that the resistance of this element is less than that of LED emitters. As a result, the leakage current will flow, for example, to an incandescent lamp. But due to the slight resistance it will not burn.

As you can see, there are many ways to solve the problem of diode-based emitters, which, although dim, still shine when turned off. It is necessary, if possible, to determine the most likely cause of this phenomenon.

The main advice is to pay attention to lighting products from reliable and trusted manufacturers. It is important to remember that high-quality diode light sources cannot be cheap. This will avoid a number of problems, the most common of which are dim light when the load is off and short service life.

Colorful temperature

Effective lighting, among other things, is also based on the compliance of the basic parameters of the light bulb with the conditions in which it will work. When choosing, the power of the product, luminous flux, color temperature, color rendering index, and luminous angle are taken into account.

If the light source lights up when the load is off due to rather poor quality, then when choosing a new product, its dimensions should be taken into account. In particular, we are talking about the size of the radiator.

This is an auxiliary design element that facilitates more efficient heat removal from the light source. Before purchasing, you need to pay attention to the correspondence between the dimensions of the radiator and the power of the lamp. If the product is characterized by a small cooler with significant power, then this design option is not worth taking.

The most reliable radiators are made of graphite, ceramics, and aluminum. Moreover, it is important that this element is not type-set.

You also need to pay attention to the quality of the connection between the base and the lamp body. It is important that there are no nicks along the edge of the holder and, in general, it should be characterized by a complete absence of play. Another key point is the level of light pulsation. High-quality lighting elements emit a uniform glow.

The difficulty of checking a lamp for light quality is that the pulsations are invisible to the eye. But craftsmen have come up with a way to solve this problem: you need to use the turned on camera of a mobile phone or camera. The pulsations will be visible because the image will begin to blink.