The light flashes with the backlight switch. And the lights go out ... and here it is blinking! What should I do? - Extra Know

The light flashes with the backlight switch. And the lights go out ... and here it is blinking! What should I do?

The light flashes with the backlight switch. And the lights go out ... and here it is blinking! What should I do?

Lighting switch manufacturers do not recommend the use of these devices in electrical circuits with large resistive loads. In other words, the light source must be an incandescent light bulb.

Often the technical passport of the product is sent along with the packaging to the unread garbage can. Immediately after using fluorescent lamps or LEDs instead of incandescent bulbs, the result of such technological nihilism appears. Even seemingly disconnected (seemingly) they blink somehow in the dark.

This not only causes psychological discomfort, but also causes premature failure.

To understand the physical nature of this phenomenon, we need to look into both the switch and the light source. Let's see why the LED lamp is blinking and what the backlight switch is.
How the device works

For backlight units, add a circuit that is parallel to the switched contacts. The main elements are lED or neon car. The resistance of this additional circuit is much higher than the shorted contacts.

If the switch is in the "On" position, electricity will not pass. And in the "off" position, it bypasses the open main contact and reaches the load.

If there is resistance, the strength of the thread is not sufficient to heat the thread.

When a fluorescent or LED lighting device is used, the load reacts because the circuit is used to ensure the operation of these light sources. It consists of capacitors, coils and semiconductor devices. It can operate with a weak current.
What is the light?

Both the LED and the emission operate on DC without operating on the AC mains voltage. For this they rectify the device (driver) current in their cellar place and create another action. For example, the final step in the control circuit of a fluorescent lamp is a high-voltage transformer, which provides the generation of arc discharge in the gaseous medium.

The LED driver circuit is rather simple. The circuit consists of a capacitor and a ballast resistor to protect the serially connected semiconductor devices so that the supply voltage is distributed between them.

All driver circuits have two common elements. The first is a diode bridge that blocks the sine wave of the alternating voltage and converts it into a pulse train of the same sign. The second is an electrolytic capacitor parallel to it. At that moment, when the voltage drops to zero, the capacitor is discharged and the interval between the pulse peaks is smoothed. Exactly this is the cause of unauthorized triggering of the lamp.

The weak current in the backlight circuit is still straightened, but the process of charging the capacitor is very slow. Eventually, when the edge is filled with electricity and the rectified voltage drops the next time, it is discharged and becomes zero. This is sufficient for short-term arc discharge in a gas environment. Or a series of connected LED chains.

When emitting, these modes can be harmful because the service life is determined by the number of starts. The blinking moment can be fully developed in a matter of minutes. LEDs for intermittent operation are more generous.
How to fix the problem

The light switch is a very practical device. It makes life easier. It is not worth giving up using modern light sources. You can use one of the following two methods to prevent the backlight from blinking due to the backlight switch.

    Increase the ballast resistance of the additional circuit.
    Use a resistive or capacitive shunt.

There is already an additional circuit breaker in the resistor (). It is installed in series with neon or LED. Raising the resistor value will make the current weaker. Then the capacitors after the rectifier bridge driver will not be fully charged due to natural losses.

The disadvantage of this method is that it is difficult to choose a nominal ballast resistor. If it is too big, the backlight stops working. Also technically very difficult. We must really have a golden hand.

The simplest resistive shunt is 40 watts. Resistance of cold filament does not exceed 100 ohms. This is less than the driver's input impedance. All the current in the backlight passes through. However, the other source of light in the chandelier - it is very ugly. But the process of paragraph is very simple.

For a circuit with a voltage of 250-400V, it can be replaced with a resistor with a nominal value of 100 ohm. The switch and cable are installed between the connected wires.

If you can not go to it (for example, it is sealed as wallpaper), the shunt resistor can be soldered to the input wire of the chandelier.

A disadvantage of this method is that the shunt resistor can be heated.

The capacitive shunt removes electricity from the capacitor and flashes the light source. Do not use electrolytic components (consequently polarity) and oil papers, expressed as ≈ and calculated for voltages of 250-400 volts. Capacity should not exceed 1 microfarad. It is mounted in the same way as a resistive shunt between the phase wire and the neutral wire.

If it is installed incorrectly, the power-off lamp will turn on. For example, if the neutral line is switched, not the switch. In addition, the flicker intensity of the luminescent house keeper is affected by the quality of the production. It is best to perform the shunting of the switch during installation.

When the power saving or LED lamp is connected to the switch with backlight, the lamp will not turn off completely or blink. Video reviews provide a solution to this problem.

Almost every household in the world can now see the switch with LED lights. It is much more convenient to use these switches in darker times, but with fluorescent and LED lamps appearing, this "handy" device is starting to cause problems.

Some modern lamps that are connected through a lighted wall switch will blink even when the light is off. The blinking effect is caused by a resistor with LED (or resistive and neon lamp) and a closed electrical circuit formed by the power converter circuit of the LED or fluorescent lamp.

There are several ways to get rid of the lamp blinking at 220V. This article considers the simplest and most reliable options in more detail. Removing the backlight from the switch. How do I turn off the backlight on the switch? First thing to do.

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