Why The Screwdriver Does Not Work

Currently, many consumers of electric energy have long been replacing incandescent lamps in their apartments and houses with LEDs or energy-saving lamps. The “Illich” lamp is gradually becoming a thing of the past, and more modern progressive light sources are replacing it. When using them, an unusual phenomenon can sometimes be observed. the lamp continues to flash after being turned off. Small flashes are especially noticeable in dark conditions. If we replace such lamps with light sources with a filament, then this phenomenon is not observed. What is the reason for this?

LED lamp features

Someone immediately begins to think about the presence of poor contact or some kind of malfunction of the chandelier. In fact, the reason lies somewhat in other circumstances. It should be sought in the design features of the lamp itself.

The operation of energy-saving light sources or LEDs is connected with a voltage of 12 volts, despite the fact that it is connected to an alternating current network with a voltage of 220 volts. The process of voltage conversion is carried out directly in the basement of the light device itself. It contains a diode bridge and a capacitor. A similar design can be represented as follows:

Connecting a backlight based on LED or neon bulbs has its own characteristics

Even if the load on the supply circuit is removed, microcurrents continue to exist in a certain amount. There are very few of them, but this is quite enough for a capacitor to accumulate a certain charging value.

It will be enough to implement the "start" of the lamp. The light source will burn. But it is too small to supply enough power for the glow. Therefore, the glow quickly stops. The light source will attempt to “catch fire” until the capacitor is discharged. Observing a similar phenomenon, they say that the lamp "blinks".

There are cases, of the year the lamp after turning off begins to glow with a dim glow. This effect is explained by the presence of insufficient resistance in the filament circuit. A similar circumstance will lead to a situation in which only a small amount is supported when charging a capacitor element.

The power is turned off, and the light source burns with a weak glow. Most often this is typical for LED lamps, and the methods of elimination are identical to the situation in which the lamp blinks.

Solution to problem number 1

Now that the cause of the problem has become clear, you can offer a fairly simple way to solve it, the use of which will allow you to effectively and quickly get rid of the unpleasant blinking of the lamp.

The procedure for eliminating the cause is as follows:

  • The circuit is opened, along which microcurrents pass. In this case, the board on the shutdown element is removed.
  • The parameters in the backlight circuit itself are replaced. This is done so that there is not enough current to charge the capacitor.
  • Currents are sent along a circuit of lower resistance.
  • Replacing the switches with another model where there is no backlight or you need to replace the lamps themselves.
Why The Screwdriver Does Not Work

Chandeliers with several lamps do not lose their popularity when installed in living rooms and other rooms

Tip # 1: There is another very simple way. In a chandelier designed for several lamps, one of the LED lamps is replaced by an incandescent lamp.

We remove the backlight

The design of backlit chandeliers includes a board that includes an LED or a small neon bulb. It is necessary to disassemble the switch, armed with a screwdriver for this, and remove this board. The backlight will not work, but the light will stop blinking.

Video: Why The Screwdriver Does Not Work

The negative point is that the scheme is associated with a strictly defined number of starts. Own stocks, as a rule, are only enough for 1-2 months. After that, we can safely say that the time has come to go to the lamp in the bin. The situation is the same in which low-power power supplies for LEDs are used.

A serious manufacturer will certainly indicate information about which lighting fixtures cannot be used with a lamp. For example, some write that when using a lamp, you should not use a backlit switch. If these conditions are not met, then the lamp will work in emergency mode. She, as it were, begins to work at the limit of her permissible loads and quickly fails.

Tip # 2: Therefore, it’s not so easy to pick up a really high-quality light bulb that will serve properly for a long time. It is necessary to pay attention to the conditions of its work when purchasing it.

Replacing the power circuit with the backlight remaining

Not every backlit switch design requires a board. In some of them, resistance is soldered in parallel with the button. If you remove it from the circuit, then the backlight will not work. But you can leave it by changing the settings. A resistance setting of 220 kOhm is required if a neon lamp is installed in the backlight and 470 kOhm with an LED.

In addition, it is necessary to solder the diode IN4007. The cathode of the diode is soldered to the resistor, and the other end to the lamp. Schematically, the chain can be represented as follows.

Modified circuit power circuit after soldering in the diode IN4007

To eliminate blinking and preserve the backlight, the old resistor is removed, and a new one with a diode is put in its place.

To get rid of the blinking effect, instead of the old one, a new resistor is soldered together with the diode

Create parallel circuit with less resistance

If a resistor is connected in parallel with the lamp, the current will be spent on heating it. In this case, in order to charge the capacitor, the current is no longer enough. In this case, the lamp flashes after turning off.

For parallel connection of the resistor, you can use a heat shrink tube or electrical tape

The power of the resistor should be 2 W, and the rating should be 50 kOhm. It is necessary to bring wires to it, and the connection point must be carefully and reliably insulated. To do this, use an electrical tape or a heat shrink tube. With relatively little heat, such insulation will be sufficient.

Eliminate reason number 2

If the design of the switch does not imply the presence of a backlight, and the LED still blinks after turning off the power, it means that some serious errors were made during the connection. A common case is a break at the circuit breaker, not a phase, but a zero. This may cause the lamp to flash:

Non-compliance with the lamp connection diagram is the most common cause of blinking after it is turned off

In this case, the only right decision is to check the connection. If an error is detected, it is corrected.

The connection is correct and the light continues to blink

In this case, the cause should be sought in the wiring condition. Most likely, the reason is poor contact due to short-term open circuits.

The reason may lie in the state of insulation of the wires. If in the first case the problem can be solved by tightening the contacts, then with poor insulation, the wiring must be replaced. The presence of insulation problems indicates the presence of a large leakage current. If there is an RCD, the line will be disconnected often.

If there is no RCD during the old wiring, then determining the cause of the blinking of the LED bulb will be very problematic. Of course, this can well be done if specialists with the appropriate equipment, including an ohmmeter, are involved. A blinking light bulb often occurs due to the presence of an old damaged wiring, as a result of which large current leaks are observed.


Question No. 1: How to choose the right LED bulb so that it does not blink after turning off?

On a box with a light bulb, each manufacturer and self-respecting buyer makes a mark for which particular lighting fixtures it is intended for. If it is written that the bulb is not suitable for backlit chandeliers. it is not recommended to put it in a lighting device. it will quickly burn out.

Question No. 2: For what reason does the light flash often?

The fact is that even after turning off the LED lamp, microcurrents continue to exist. Their value is too small to allow the lamp to burn, but it is quite enough for the capacitor to accumulate a charge for blinking.