LEDs flicker

Why are my led lights blinking ?

Well. put simply, LEDs flicker when their LED flood light output fluctuates. This fluctuation happens because your dimmable light-emitting diodes are designed to switch on and off at very high speed.

Even though you don’t always see it, all mains-powered light sources flicker – whether incandescent, halogen, fluorescent or LED.

In the UK, mains electricity is an alternating current (AC) supply, delivered at a frequency of 50 hertz. Which means the electric current that powers your lights – any lights – switches backwards and forwards 50 times each second.

We didn’t used to notice it with our old incandescent bulbs, because the bulb’s residual heat kept the filament glowing between flickers. This was a side-effect of the inefficiency of traditional bulbs. These old incandescents typically wasted around 90 percent of input energy through heat!

LED light blinking fast

But if all lights flicker, why do some people think flickering LEDs are a problem?

LED flicker used to be a common problem. This was because – unlike incandescents, halogens and fluorescents – LEDs have no persistence. When the power supply to an LED is switched off, the light output stops instantly. So if connected directly to an AC mains-electricity supply, an LED will switch on/off 50 times each second – enough to be visible to the human eye.

That’s why some people think LEDs flicker more than older light sources. In the past, that used to be true. But it’s not true today.

LED flicker isn’t a problem for modern LED installation projects. This is because we don’t connect the LEDs directly to the mains supply anymore. Instead, we power our LEDs using an LED driver especially designed for the purpose.

Why do led lights flicker when turned off ?

This is usually due to incompatibility between the driver and the control system. When purchasing an LED product, it is important to use the correct driver type as specified by the manufacturer. It is also important to check that the LED is dimmable. Some retrofits are not.

LED bulbs are used in flood spot light fixtures to produce reliable, bright color, energy efficient outdoor lighting. LED flood lights may flash or flicker for many reasons. Common causes include:

Fluctuations in the home or building’s voltage, such as when other appliances or electrical systems are in use, causing fluctuating loads.

High watt surges when an appliance or electrical system is turned on.

Loose connections, between the bulb and fixture or wiring within the fixture.

A bad dimmer switch. LED lights must operate with appropriate dimmers – the same dimmers you use with incandescent or halogen bulbs can actually cause flickering in LEDs. These switches reduce the volts to produce a dimming effect, which is not appropriate for LED bulbs.

LED lights filcker on dimmer switch

Another challenging variable for LED lamps to avoid flickering is through dimming. Most standard wall dimmers work by phase cutting, which removes part of the sine wave and reduces the voltage. However, this can have negative affects on an LED circuit and actually result in the flicker effect being amplified to a potentially dangerous level (3-15Hz range).

This is one of the main reasons why it’s hard to trust old dimming systems with new LED bulbs. The only way to be sure no flickering will be present is to get LED-specific dimming solutions for your LED lamps. It all comes back to the fact that LED is a long-term investment. In turn it is worth doing research to ensure you are getting a quality LED bulb, and that if you plan to dim with it you are getting an LED dimming system that has been tested as being compatible to the LED bulbs you intend to use.

How to solve LED flickering issues?

LED flickering can be tied back to the driver component within the lamp. The essential purpose of the LED driver design is to rely on a simple circuit to control output current, but without altering the frequency, the LED becomes likely to show visible flicker. However, this can be fixed by using constant current drivers, which remove the peaks of the sine wave.

Power correction components within the driver circuit must also be addressed. Without this, ripple currents in the power flow will cause flickering.

Ultimately if the driver design of the LED bulb meets the requirements of both a stable DC current and ample ripple suppression, there should be no flicker. If flickering is present in your LED lamp (and you are not dimming with it), it was likely created with cheap driver components. The technology in LED lighting has advanced to the point where this should not happen, unfortunately there are companies that care more about their bottom line than the health of their customers.

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