Before we start today’s topic, we can not “not business”, first look at the production process of LED fluorescent lamps:.
Now the production of LED lights first after a rigorous computer programming production, production of good light board, and then into the assembly plant assembly line, the specific we will not expand.
We all have such a life experience, just bought back the LED lights, always particularly bright, but after a period of time many lights will become increasingly dark, why LED lamps and lanterns will have such an over
What about the program?
Today we will take you to find out! To understand why your home LED lights will get darker and darker, we have to understand a professional term – LED light decay.
LED light decay refers to the LED after a period of time after the light, its light intensity than the initial light intensity will be reduced, and can not be restored, that is, the reduced part is called LED light decay.
/light decay curves/
The more LED lights are used, the darker they are because LED lights will have the phenomenon of light decay.
The light decay of LED light products is the weakening of the signal in the transmission of light, and at this stage of the global LED manufacturers to make the light decay of LED products are different, high-power LED light decay also exists, which and the temperature has
The direct relationship is mainly determined by the chip, fluorescent powder and packaging technology. At present, the white LED on the market whose light decay is one of the primary problems to civilian lighting.
Light failure generally refers to its luminous flux, when charging the surface of the photoconductor drum, with the accumulation of charge on the surface of the photoconductor drum, the potential also rises, and finally reaches the “saturation” potential, which is the highest potential
The surface potential decreases over time and is generally lower than this potential at the time of operation. This natural decrease in potential over time is called the “dark decay” process. Photoreceptor Drum
After scanning exposure, the potential in the dark region (the surface of the photoconductor not irradiated by light) is still in the dark decay process; the carrier density in the photoconductor layer in the bright region (the surface of the photoconductor irradiated by light)
The conductivity rises rapidly, forming a photoconductive voltage, the charge disappears rapidly, and the potential of the photoconductor surface falls rapidly. This is called “light decay”.
The more LED lights are used, the darker they become, is a very common phenomenon. In addition to light failure, LED lights can be dimmed for no other reason than the following two points.
Drive damage
LED lamp beads require low DC voltage (below 20V) to work, but our usual utility power is AC high voltage (AC 220V). To turn the utility power into the electricity needed by the lamp beads, a device is needed that
It is called “LED constant current driver power supply”.
Theoretically, as long as the parameters of the driver match the lamp bead board, it can be continuously powered and used normally. The driver is relatively complex internally, and any device (such as capacitors, rectifiers, etc.)
(etc.) failure, may cause a change in output voltage, which in turn causes the lamp to dim.
Driver damage is one of the most common failures in LED luminaires, which can usually be solved by replacing the driver.
LED burnout
LED itself is a combination of one by one beads, if one or part of it does not light up, it will inevitably make the whole lamp dark. The beads are generally connected in series and then in parallel – so a certain
A burned out lamp bead may cause a group of lamp beads are not bright.
There is an obvious black spot on the surface of the burned lamp bead, find it and short it out with a wire connected to its back; or replace it with a new lamp bead, both of which can solve the problem.
LED burned occasionally a, may be a coincidence. If frequent burning, consider the driver problem – another manifestation of driver failure, is to burn the lamp beads.
Why does the LED light flicker and what is the cause of the flickering LED light.
The drivers of LED lights have a capacitor inside, which can be understood as a rechargeable battery with a very small capacity: when a current passes through the capacitor, the capacitor is continuously charged – and after it is fully charged
The capacitor will release all the stored electrical energy at once.
The LED light blinks, it belongs to the latter case: the light is off during the charging of the capacitor – the charging speed is very slow due to the low current inside the capacitor, so it can be seen with the naked eye
The electric light goes out. When the capacitor is fully charged, it releases electrical energy at once and will light up the electric lamp. But because the stored electrical energy is small, the electric light will go out soon – keep charging and discharging repeatedly, the
What the naked eye sees is the lights flashing.
The flicker is not visible when the lamp is in normal use because the current through the capacitor is high and the charging rate is extremely fast.
So, what can cause a smaller current to flow inside a capacitor? First of all, it is because the capacitor is of bad quality – a good quality capacitor, which stores a lot of power, does not have enough tiny current in the line to
Energy is stored in the capacitor. The average starter is only about twenty dollars, and I’m afraid the cost of a quality capacitor is more than twenty dollars.
In addition to this, we can also start from the source of the tiny current.
Possibility 1: Switch control zero line
The switch controls the zero wire, which represents the fire wire is directly connected to the electric light (capacitor). While the fire wire has a high potential, if there is a low potential in the line at this point, a potential difference is formed – a potential difference
of another name, called voltage. Only at this time, the potential difference is much smaller compared to 220V. Voltage is added to both ends of the capacitor, it will produce a weak current
The correct wiring of a single control switch
The correct way to connect the dual control
Therefore, the fire wire directly into the electric lights, will inevitably lead to LED lights flickering. This is a construction problem, in addition to changing the direction of the zero fire wire, there is no other way.
Possibility 2: Zero line charged
Electric lights (capacitors) are connected to the zero potential of the zero line at both ends, everything will be fine? Not quite! The zero line is easy to carry electricity – especially the zero line of the lamp.
Mainly because the light switch is too
It’s not reliable anymore.
Nowadays, the quality of the internal structure of the light switch is very worrying. The distance between the zero and fire terminals is too close, the insulation is not qualified, etc., may cause the zero line of the lights with electricity. Do not believe you can disassemble yourself
Home has been connected to the switch, use the electric pen to test – in theory, when the switch is closed, only the firewire terminals can light up the electric pen. But the actual use, connected to the zero line (lamp line)
Nine times out of ten, the wiring posts can also light up the electric pen.
Only most switches, even if the zero line is charged, the voltage carried is relatively low and not enough to generate a current in the line. However, if the insulation is a little worse and the current generated is slightly higher, it will give
Capacitive charging.
One more thing: When the switch is equipped with an indicator light, the light will come on when the light is turned off, at which time a weak current needs to be generated – this current will flow through the capacitor and be stored by the capacitor. These conditions
The situation can be solved by replacing the switch with a better quality one without indicator light.
Possibility 3: Induced electricity
If there are more wires around the capacitor, the other wires will cause induced electricity near the capacitor when they are working – a sentence explaining the cause of induced electricity: two conductors are placed parallel to each other, forming
New capacitors.
Most people are helpless in the face of this situation, and there are two solutions at this point.
1) Replace the electric lamp with a fluorescent lamp or incandescent lamp.
2) Connect a 220V relay coil in series with the starter of the LED lamp. Use the coil to consume the induced electricity generated by the line.
