Why do LED bulbs get dimmer the more they are used? Why is it flickering?

Now production of LED fixtures must first go through careful computer programming, make light panels, and then enter assembly line of assembly shop. We won't go into details.

Everyone has this life experience

The LED bulbs I just bought are always very bright,

But after a while, many lights will become dimmer,

Why do LED lamps use this process?

Get to know everyone today!

To understand why LED lights in your home are getting dimmer

First you need to understand professional term

LED light fading

LED light fading

LED light attenuation means that after LED is turned on for a certain period of time, its light intensity will decrease from initial light intensity and it cannot be restored, that is, reduced part is called light attenuation of LED.

/Fade curve/

The more you use LED lights, dimmer they will be because LED lights will fade.

The light attenuation of products with LED lamps is attenuation of light signal during transmission. At present, LED products produced by global LED manufacturers have different degrees of light attenuation. High-power LEDs also have light attenuation, which is directly The relationship is mainly determined by chip, phosphor and packaging technology. At present, light attenuation of white LEDs on market is one of most important issues when entering civil lighting market.

Light attenuation generally refers to its light output. When charging surface of photosensitive drum, since charge is accumulated on surface of photosensitive drum, potential will continue to increase and finally reach "saturation" potential, which is highest potential. The surface potential will decrease over time, and operating potential is usually below this potential. The process of naturally decreasing this potential over time is called "dark decay" process.

When photosensitive drum is scanned and exposed, potential of dark region (meaning surface of photoconductor that is not irradiated by light) is still in process of dark fading; increases rapidly, conductivity rises rapidly, forming a photoconductive voltage, charge quickly disappears, and surface potential of photoconductor also decreases rapidly. Call it "light decay".

It is very common for LED bulbs to dim as they are used. Besides light fading, causes of dimming LED lights are none other than following two points.

01

Disk damaged

LED lamps are supposed to operate at low DC voltage (below 20V), but our regular mains is powered by high voltage AC (220V AC). To turn mains electricity into electricity needed for lamp beads, a device called a "DC LED drive power supply" is needed.

Theoretically, as long as driver parameters match lamp board, it can continue to supply power and work normally. The internals of a driver are relatively complex and any failure of any device (such as capacitors, rectifiers, etc.) can cause output voltage to change, which in turn causes lamps to dim.

Driver corruption is most common LED lamp failure and can usually be fixed by replacing driver.

02

LED burned out

The LED itself is made up of lamp beads, one by one. If one or part andof them is not lit, this will inevitably lead to fact that entire lamp goes out. Lamp beads are generally first connected in series and then in parallel, so if any lamp bead burns out, it can cause a batch of lamp beads to fail to light.

There are obvious black spots on surface of burnt lampshade. Find it, wire it to back and short it out or replace it with a new lampshade, that will solve problem.

The LED sometimes burns out alone, perhaps by coincidence. If it burns frequently, think of a problem with driver - another manifestation of a driver malfunction is burnt lamp beads.

Why is LED blinking? What is reason for flashing LED. . .

There is a capacitor in LED lamp driver. A capacitor can be understood as a battery with a small capacity: when current passes through capacitor, capacitor will continue to charge - after fully charged, capacitor will store stored energy at one time, electrical energy is fully released.

The flickering of LED refers to latter situation: during charging process of capacitor, light goes out, because internal current of capacitor is small, charging rate is very slow, so light can be seen to go out with naked eye. When capacitor is fully charged, electrical energy is released in one go and light turns on. However, due to small amount of stored electrical energy, electric light will soon go out - recharging and discharging are repeated continuously, and light can be seen flickering with naked eye.

During normal use, lamp does not flicker because current through capacitor is relatively large and charging rate is extremely fast.

So, what causes a small current to flow inside a capacitor? First of all, because quality of capacitor is not very good - a quality capacitor stores a lot of energy, and tiny current in line is not enough to store energy in capacitor. The general starter is only about 20 yuan, and cost of quality capacitors is probably more than 20 yuan.

Alternatively, we can also start with a source of tiny currents.

Possibility 1: Switch neutral control line

The switch controls neutral wire, which means that energized wire is directly connected to lamp (capacitor). While line is energized at a high potential, if at that time there is a low potential in line, then a potential difference will form - another name for potential difference is called voltage. It's just that potential difference at this time is much less than that of 220V. When voltage is applied to the capacitor, a small current is generated.

Proper wiring of a single switch

Correct way to connect dual controls

Thus, if a live wire is directly connected to a light source, it will inevitably cause LED to flicker. This is a design problem, and there is no other way out but to change direction of zero-fire line.

Possibility 2: neutral line is charged

The two ends of lamp (capacitor) are connected to a neutral line with zero potential, so everything is in order? Not really! The neutral wire is easy to charge, especially light bulb neutral wire. Mainly because light switches are so tricky.

The quality of internal structure of current switch is very worrying. The distance between terminals of neutral and live wires is too small, insulation does not meet standards, etc., which can lead to electrification of neutral wire of lamp. If you don't believe me, you can take apart switch that was wired in your home and test it with an electric pen. Theoretically, when switch is turned off, electric pen can only light a live wire terminal. But in real conditions, a terminal connected to neutral line (light line) in all likelihood can also ignite an electric pen.

It's just that for most switches, even if neutral line is charged, transmitted voltage is relatively low, which is not enough to create current in line. But if insulation is even worse, generated current will be somewhat larger, which will charge capacitor.

Another point: when there is an indicator on switch, indicator lights up when light is turned off. At this time, it is necessary to generate a weak current - this part of current will flow through capacitor and accumulate in capacitor. These situations can be resolved by replacing switch with a better quality switch without an indicator light.

Option 3. Inductive electricity

If there are many wires around capacitor, when other wires are working, it will cause inductive electricity next to capacitor - one sentence explains reason for inductive electricity: two conductors are placed in parallel to form a new capacitor.

Most people are helpless in face of this situation. There are currently two solutions:1) Replace bulb with a fluorescent or incandescent bulb. 2) Connect a 220V relay coil in series to LED lamp starter. Use coil to consume induced electricity generated by line.