Why do LED Lights Flicker when Turned off?
Why do LED lights flicker when turned off
LED lights are lighting devices used by people to light their houses, workplaces etc. These are lights that emit light with the help of one or more light conducting diodes.
One of the common problems faced by people when using LED lights is that they flicker when they are being turned off. This is a common problem reported by many who make use of LED lights.
This is a problem that is caused by technical errors that are easy to overcome in many circumstances. This flickering problem is so common that people think that it is an inherent problem that is inbuilt within the LED lights.
A good example to understand the flickering issue is a software bug that makes a software program defective; the bugs may affect the program but they are fixable just like how the flickering can be stopped in an LED light.
The reasons for LED lights flickering once turned off
The flickering of the LED light is usually a technical defect that comes with the LED Light and is not a defect of the product itself. A few of the reasons that might cause LED lights to flicker are being discussed below.
Incompatible dimmer switch
The first and foremost reason for the LED lights to flicker when turned off is that they might have been installed along with an incompatible dimmer switch. An incompatible dimmer switch will cause the LED light to flicker for a very few seconds or for a minute ( at the maximum) when being turned off.
The incompatible dimmer switch not only creates a flickering of the lights but sometimes might cause a buzzing sound as well.
This flickering and in some cases buzzing can be fixed by replacing the dimmer switch and using the one which is compatible with the LED light. There is a difference between the power used by incandescent bulbs and LED bulbs.
A 40W incandescent bulb needs lesser power than a 9W LED bulbs. So, when a person changes from incandescent bulbs to LED lights, they should upgrade their switch with the help of a professional.
Power remaining in the circuit
One of the common reasons for the flickering of the LED bulbs could be because there is a little amount of power (current) still left in the circuit, thereby making the lights flicker for a fleeting moment.
This flickering is neither a dangerous thing for the product nor a danger to the person using it. The only problem with the flickering is that it might cause a slight dent in your power bills. This is considered annoying by the majority of the users of LED bulbs.
The technical explanation for this reason for flickering is that a small amount of current is still passing through the cables and is picked up due to electromagnetic induction. As the level of current is very low it only makes the lights flicker and not glow for a long period of time.
Unearthed wiring may also contribute to the flickering of LED lights. Unearthed wiring is when the wires or cables are exposed to threats like storms, lightning and other phenomena that can damage the flow in the cables. This can cause severe damage and might even become lethal when left unchecked.
This flickering happens when the wires are not earthed or when the earthed wire has too high a resistance that creates a minute current that flows through the circuit to cause the flickering of lights for a few seconds.
This can be corrected by earthing the wire. Earthing the wire is when wires or cables are laid down into the earth rather than being exposed to open surfaces that might cause physical damage to them.
Though this could be one of the rare reasons for the LED lights flickering when they are turned off, we do want to make a mention about it. Using two way switches can cause the flickering issue in certain rare cases. This is when an electronic device can be operated with the help of two switches.
This is explicit only in the case of LED bulbs and not incandescent bulbs. This is because of the diodes used by LED bulbs. They conduct electricity even with minimal flow of current through their cables and thus create the flicker.
Flickering LED lights and non-flickering incandescent bulbs
The flickering bulbs phenomenon is only attached to LED lights and not with incandescent bulbs. This is because the LED lights use diodes which only need a very little amount of current to make the lights glow.
The diodes are semiconductor devices, which allow the current to flow through a single direction at a particular time and not both the direction at the same time.
So, they carry even the smallest amount of current that is there in the cables when the circuit is switched off. Incandescent bulbs, on the other hand, use the filament, which gets heated up because it resists the flow of electrons and thus creates light.
Preventing the Flickering of LED bulbs/lights
The LED lights can be corrected in such a way that they don’t flicker every now and then when they are turned off in the following ways :
- By making sure that the wires and cables are earthed properly and the wires are monitored so that they don’t have any high resistance than they normally need.
- By making sure compatible switches are used instead of incompatible switches; a compatible switch helps in maintaining a proper amount of current.
- By having a thorough check of the electric circuit in which the flickering bulb is connected. This will need the help of an electrician.
- By using a Zener diode. ( Zener diode is a conducting device which helps in the flow of current in both directions at the same time unlike a normal diode).
The flickering of LED lights, when turned off, is a problem known worldwide and is not much of a threat, when properly handled with care. This condition is totally avoidable if the right measures are taken. It is just an inconvenience that can be caused for a very few seconds because it drives people crazy!