Why LED light blinks - elimination of flickering

LED lamps are the most modern light sources. They are economical, reliable, efficient and long lasting. LEDs are safe for human eyes and the nervous system, as they are free of pulsations when properly designed and connected. If violated, there may be flickering that needs to be corrected.

Principle of operation and device

LED bulbs are more complex than incandescent or halogen bulbs. The design includes the following details:

• Hemispherical diffuser. Made of plastic or glass.
• LED matrix.
• Aluminum plate for heat dissipation.
• Radiator.
• Driver. It is because of the low-quality driver that the light bulb blinks most often.
• The base of the plinth is made of polymer.
• Base / plinth.

The design may vary depending on the type of light bulb.

In classical light sources, voltage was applied directly to the spiral, which served as an active resistance. LED contains special converters - drivers. When power is applied, the current flows through the base to the converter, and then to the LED matrix itself. The converter changes the current and voltage to the values ​​that are optimal for functioning.

The following main reasons for lamp flickering can be distinguished:

• Constant surges of electricity.
• Low voltage in the network.
• Malfunction of components in the circuit.

The breakdown must be found and eliminated as soon as possible.

Reasons for flickering of cheap lamps

Cheap products from little-known manufacturers often do not correspond to the declared characteristics. The decrease in the cost of goods is associated with the use of low-quality materials and savings on electronic components. This can be seen in cheap LED bulbs that start blinking almost immediately after purchase. The manufacturer installs cheap drivers, does not use heatsinks, and this affects the operation of the device.

Blinking of the lamp is common, but in most cases the device remains operational. If the cause of the blinking is eliminated, the lamp can be used for the time specified by the manufacturer without harm to health.

In cheap devices, it is not always possible to troubleshoot a problem. For this reason, it is recommended that you immediately buy a verified device from a reliable supplier. At the stage of purchase, it will cost more, but all the declared characteristics will correspond to the operating parameters.

Lamp flickering due to poor quality power supply

It's not just cheap light bulbs that ripple. Mid-range fixtures may also include a cheaper power supply in their design, which will cause flickering at startup.

The power supply unit consists of the following elements:

• Diode bridge with capacitive filter.
• Quenching capacitor.

An alternating current is supplied, which flows through the diode bridge. When passing through, it is converted into a direct current of the required magnitude, but with a high ripple.A capacitive filter and a damping capacitor reduce flicker. The equalized current flows to the lighting fixture, due to which the lamp operates normally. In the case of using low-quality components, the circuit will not be able to achieve the desired characteristics, which will cause flickering.

Blinking can be detected both on one light bulb and on a whole group. The reasons for this phenomenon are the same, and they must be eliminated so that the working resource of the devices does not decrease. The malfunction can manifest itself in the off and on state.

Flashing when off position

Ripple when the circuit breaker is inactive can be detected due to the ingress of electric current into the smoothing capacitor. It accumulates current, which, when filled, enters the circuits and tries to activate the LED lamp. This reserve is not enough for full functioning, so the lamp will light up for a short period of time. The blinking will be repeated until the problem is eliminated or the lamp breaks.

The following components can affect the flashing of lamps:

• switch illumination;
• induced voltage;
• leakage currents.

You need to know these reasons in order to be able to quickly eliminate them.

Influence of switch illumination

Many manufacturers equip their switches with backlighting. It increases the comfort of use, as the switch starts to light up and becomes easier to find in the dark.

But extra backlighting can cause flickering, especially on cheap bulbs. This is due to the parallel connection. In the off state, the current goes to power the backlight, and when turned on - to the lamp.

This reason is one of the most common, therefore, it is the switch illumination that you need to pay attention to when the lamp flickers.

Induced voltage

Occurs when several devices are connected to one multicore cable. It can also be observed when laying several independent lines in one strobe.

You can fix the problem by replacing one LED light bulb with a lower wattage device. For a while, you can put an incandescent lamp, but you need to remember that it will also be affected by the induced voltage. The best solution would be to change the section of the electrical wiring and allocate a separate line for the lighting group.

Leakage currents

Leakage current is the most dangerous reason a light blinks. It appears due to poor quality and improper installation, damage to the insulation, poor contact. This results in an open circuit that could lead to fire. Even in a non-working state, currents will flow to electrical appliances.

Remedies

If the lights flash due to the backlight on the switch, open the circuit. There are 6 main ways to troubleshoot the problem:

• shunting with a resistor;
• capacitor shunting;
• connecting the backlight with a separate wire;
• use of a pass-through switch;
• dismantling the backlight inside the switch;
• the inclusion of a parallel LED light bulb.

Turning off the switch backlight is the easiest way. To begin with, the switch is dismantled, and the wires for the backlight are disconnected. You can also replace the old switch with a new one. It is recommended to take a device with neon illumination - it flickers less frequently than LED.

When a group of light sources blinks, you can replace them with one incandescent lamp with a low power. The flickering should disappear, but it must be borne in mind that the aesthetic properties of the chandelier will be violated.

Installing a low-power 50K resistor for 2W of power helps to troubleshoot the problem. The work must be carried out with high quality, otherwise there is a risk of fire.All contacts must be securely insulated.

Blinking can occur due to insulation problems. Violation of its integrity leads not only to unstable operation of the lamp, but also to danger to human health.

Leakage currents can be eliminated only by repairing problem sections of the circuit. Sometimes it may be necessary to replace all electrical wiring in an apartment or house.

Blinking light when the switch is on

If the switch is active, two reasons for flashing can be distinguished:

• Weak tension. Any light source is sensitive to low voltage. If a high-quality driver is installed in the LED bulb, stable operation can be achieved even at 180 V. Lamps without a high-quality driver are turned off already at 200 V. Flickering at voltages below 220 V will be observed with different frequencies and will stop when normal operating values ​​are reached.
• Poor quality power supply. If the mains voltage is normal, the problem may be related to the power supply unit. The use of low-quality elements will not allow the device to equalize the current and bring the values ​​to the optimal level.

The malfunction also manifests itself when dimming a light bulb that is not intended for this function. Then the user will observe flickering when the brightness is lowered. Stable, ripple-free operation will be noted if the lamp is turned on immediately at maximum brightness. Remove the unsuitable lamp and install a special dimmable light source.

There are two ways to identify the cause of flickering when turned on:

• Using a pencil. In a completely dark room, only the lamp under test should be switched on. In front of him, you need to quickly draw a pencil. If there is a solid trail behind it, there is no flicker. If the trace is intermittent, pulsations are present.
• Test with a camera on a smartphone. You need to turn on the light bulb and point the camera at it at a distance of about a meter. When flickering, dark bands will appear on the screen. If there is no blinking, the image will be uniform and of the same color.

LED lamp flashes after power on:

• In case of voltage surges, a stabilizer is installed. It brings the current to the desired parameters and at the same time prevents premature breakdowns of electrical appliances.
• The power supply can be upgraded by yourself. To do this, you should select a high-quality smoothing capacitor and put it in the circuit.

Users with electrical engineering skills will be able to make a reliable driver on their own.

How to determine the cause of the blinking

When troubleshooting an LED lamp, promptness is essential. The sooner the breakdown is identified and corrected, the longer the light source will last. If the damage is related to wiring or insulation, the failure may result in fire or electric shock to a person.

Checking algorithm:

• Phase wire check. It must connect correctly to one of the contacts on the switch. If current flows to the backlight, the LED will blink. You can determine the phase using an indicator screwdriver or a tester.
• Measurement of ambient temperature. Temperatures above 50 degrees do not allow the lamp to work stably, so you need to lower the temperature or move and install the lamp to another place.
• Replacing the backlit switch with a device without it, or turning off the backlight.
• Installing a low-power incandescent lamp instead of one LED.
• Inspection of electrical wiring, insulation quality.
• Checking the voltage stability when flickering in the on state.

When all parameters are normal, it is recommended to change the LED lamp to a high-quality analogue of a well-known brand.