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In some cases, when the light is off, the light bulb blinks. The phenomenon is unpleasant for the eyes, and also significantly reduces the life of the lamps. Why this happens and how to deal with it, let’s talk further.
Cause #1 of blinking LED and energy-saving lamps
If you have switches with LED or neon illumination, when you install economy lamps (they are also called energy-saving or compact fluorescent lamps), they start blinking when the light is off. The same situation is observed with some (cheap Chinese) LED lamps. They turn on briefly – for a fraction of a second – and instantly turn off. It repeats quite often – every couple of seconds.
The reason is simple. The LED or fluorescent lamp blinks when the light is off due to the presence of the backlight LED power circuit and the design features of these lamps. Unlike incandescent lamps, energy-saving and LED lamps operate on 12 V DC. But they are connected to a 220 V network, and the conversion takes place in the lamp base, where a diode bridge and a capacitor are installed – a circuit that converts 220 V AC to 12 V DC .
When you turn the switch to the “off” state, there is still a power circuit for the LED / neon lamp, which is why they glow. Microcurrents flow through this circuit – no more is needed for illumination. They are small, but they are enough for the capacitor in the lamp to accumulate enough charge to start the lamp (which is installed in the lamp base). As a result, the lamp lights up. But, since the charge is still too small and there is no normal recharge, the lamp quickly goes out. This is where blinking comes in.
Sometimes – with some switches – The lights don’t flicker, they stay on. This is because the resistance in the backlight power circuit is low. As a result, the current is enough to maintain a small charge on the capacitor. Therefore, it turns out that the lamps are lit when the light is off. Most often this affects LED lamps (light-emitting diode). The methods of dealing with this phenomenon are the same as with blinking.
The situation when the light bulb blinks when the light is off is not only unpleasant for the eyes. There is another consequence: each lamp is designed for a certain number of on-off. When blinking, this cycle occurs in a fraction of a second. There can be 10 or more per minute. It is clear that very soon the lamp will fail. So it is necessary to deal with the fact that when the light is off, the light blinks, immediately after detection.
Fixing Problem #1
After you understand why the energy-saving light blinks when the switch is off, it’s easy to suggest a solution to the problem:
- Open the circuit for the passage of microcurrents by removing the backlight on the switch.
- Change the parameters of the backlight power circuit so that the current is insufficient to charge the capacitor.
- Wrap the currents in a circuit with less resistance.
- Replace the switch with a non-illuminated model or install other lamps.
Why does the LED light blink when the light is off
If we are talking about a chandelier with several horns, there is another way – you can screw an incandescent lamp into one of the horns.
The method is quite simple, but it works. If single bulbs flicker, the phenomenon will have to be dealt with by other methods. With the replacement of switches and lamps, there will probably be no questions, but with other methods they may be.
We remove the backlight
In switches with built-in lighting, there is a board on which there is an LED or a small neon lamp, resistance and contacts (usually in the form of springs). This board is located under a small plastic cover on the back of the switch housing. To get to it, you need to disassemble the switch.
The cover can be pry off with a fingernail or a screwdriver. Having removed it, on the reverse side we find a board.
We take this fee. It is not attached to anything, just hook it up and remove it from the latches. We put the cover without a board in place, assemble the switch and check its operation. Everything should work, except for two things: the backlight does not turn on when the light is off and economical or LED lamps do not blink.
We leave the backlight, changing the parameters of the power circuit
Not all illuminated switches are made using circuit boards. More budget models are made simpler: a resistance is soldered to the diode and this circuit is installed in parallel with the switch keys (as in the photo below).
In this case, you can solder / bite out the LED and the resistor and get a regular switch without backlight. But you can change the parameters of this circuit so that the backlight will work, and the lamps will not blink or burn when the light is off. To do this, you will have to replace the resistor – put the resistance:
- not less than 220 kOhm, if the backlight is with a neon lamp;
- not less than 470 kOhm or 680 kOhm with LED backlight (selected on site).
Besides? a 1N4007 diode is built into the circuit behind the resistance, cathode to the resistor. The second input of the diode is soldered to the backlight. As a result, the power circuit will look like the figure below.
To eliminate the blinking of the lamps and keep the backlight on the switch, we unsolder the old resistor, put a new one along with the diode. After that, the switch can be assembled and put in place.
In most cases, the problem disappears. If the lamp is still flashing, it is necessary to replace the resistance with a larger one. This is rare, but…
We create a circuit with less resistance in parallel with the lamp
If you connect a resistor in parallel with the lamp, the current will go to heat it up, the lamp capacitor will remain without a charge, there will be no blinking. The resistor is usually taken for 50 kOhm and a power of 2 W, wires are soldered to it, and then insulated, leaving only two wires outside for connection. You can wrap it with electrical tape or use heat shrink tubing.
First, the junctions of the conductors and the legs of the resistance are insulated, then another layer of insulation is applied, which also covers the resistor. The currents are small, if there is heating, it is quite insignificant, but with such a two-layer insulation, this alteration is safe.
There are two ways to mount this resistor: in a junction box or directly on the luminaire. It is only important that it is connected in parallel with the lamp.
You connect the previously prepared insulated resistor to the same places – this is much safer. In the junction box, the connection is similar. You need to find two wires that go to the lamp, and connect additional conductors to the same contacts. After such an alteration, the light will not flash. But if you are not strong in electrics, be very careful.
We remind you once again that all these works must be carried out with the power turned off in the shield.
Reason number 2 and its elimination
If your switch is without backlight, and the LED or economy lamp flashes when the light is off, then there is a connection error. Most likely, it is not the phase that breaks on the switch, as it should be, but zero. In addition to being very dangerous, it leads to such a phenomenon – the flashing of some lamps.
This is eliminated by correcting the error – you need to check which wire the phase is on and connect the switch correctly. If all the switches on this line are connected incorrectly, you can throw the wires in the shield. If only a part – you will have to do this on each incorrectly connected switch.
Reason number 3: why the light blinks if everything is connected correctly
Sometimes the switch is without illumination, and the phase enters it, but the light still blinks when the light is off. Then the reason is the poor condition of the wiring. Maybe it’s a contact, or maybe it’s a problem with insulation. If the contacts can be tightened, welded, re-wired, then problems with insulation are solved only by a complete replacement of the wiring.
One point: problems with insulation – this means a large leakage current. If you have an RCD (residual current device) on your line, it will often turn off the line. If there is no RCD and the wiring is old, you will not determine this in any way. Rather, it can be determined using an ohmmeter and the involvement of specialists. In case of significant damage, you can verify the presence of this problem with a multimeter and continuity of the wires “to ground”. Well, the light bulb blinks – this is a particular manifestation of the fact that the insulation is damaged and there are significant leakage currents.