Resistance for a neon lamp is 220. Illumination circuits for electrical switches
Schematic diagrams of simple indicators of the presence of a 220V network on LEDs, we replace old neon indicator lamps with LEDs. In electrical equipment, neon indicator lamps are widely used to indicate that the equipment is turned on.
In most cases, the circuit is as in Figure 1. That is, a neon lamp is connected to an alternating current network through a resistor with a resistance of 150-200 kioles. The breakdown threshold of a neon lamp is below 220V, so it easily breaks through and glows. And the resistor limits the current through it so that it does not explode from excess current.
There are also neon lamps with built-in current-limiting resistors; in such circuits, it seems as if the neon lamp is connected to the network without a resistor. In fact, the resistor is hidden in its base or in its lead wire.
The disadvantage of neon indicator lamps is their weak glow and only pink color, and the fact that they are glass. Plus, neon lamps are now less common on sale than LEDs. It is clear that there is a temptation to make a similar power indicator, but on an LED, especially since LEDs come in different colors and are much brighter than “neons”, and there is no glass.
But, LED is a low-voltage device. The forward voltage is usually no more than 3V, and the reverse voltage is also very low. Even if you replace a neon lamp with an LED, it will fail due to the excess reverse voltage at the negative half-wave of the mains voltage.
Rice. 1. Typical diagram for connecting a neon lamp to a 220V network.
However, there are two-color two-terminal LEDs. The housing of such an LED contains two multi-colored LEDs connected back-to-back in parallel. Such an LED can be connected in almost the same way as a neon lamp (Fig. 2), only take a resistor with a lower resistance, because for good brightness more current must flow through the LED than through a neon lamp.
Rice. 2. Diagram of a 220V network indicator on a two-color LED.
In this circuit, one half of the two-color LED HL1 operates on one half-wave, and the second on the other half-wave of the mains voltage. As a result, the reverse voltage on the LED does not exceed the forward voltage. The only drawback is the color. He is yellow. Because there are usually two colors - red and green, but they burn almost simultaneously, so it visually looks like yellow.
Rice. 3. Diagram of a 220V network indicator using a two-color LED and a capacitor.
Figures 4 and 5 show a circuit of a power-on indicator on two LEDs connected back-to-back. This is almost the same as in Fig. 3 and 4, but the LEDs are separate for each half-cycle of the mains voltage. LEDs can be either the same color or different.
Rice. 4. 220V network indicator circuit with two LEDs.
Rice. 5. Diagram of a 220V network indicator with two LEDs and a capacitor.
But, if you only need one LED, the second one can be replaced with a regular diode, for example, 1N4148 (Fig. 6 and 7). And there is nothing wrong with the fact that this LED is not designed for mains voltage. Because the reverse voltage across it will not exceed the forward voltage of the LED.
Rice. 6. 220V network indicator circuit with LED and diode.
Rice. 2. Diagram of a 220V network indicator with one LED and a capacitor.
In the circuits, two-color LEDs of the L-53SRGW type and single-color LEDs of the AL307 type were tested. Of course, you can use any other similar indicator LEDs. Resistors and capacitors can also be of other sizes - it all depends on how much current needs to be passed through the LED.
Andronov V. RK-2017-02.
There are backlit switches on sale, but rarely does anyone get around to replacing one that is already installed without backlighting and is still in good working order.
After spending half an hour, anyone who wants to improve the comfort of night life will be able to add lighting to the switches in their apartment on their own, even without the skills of an electrician.
You can install the backlight switch according to one of the proposed schemes. The circuits differ not only in configuration, but also in technical characteristics. For example, an LED circuit may not work if the luminaire contains LED lamps. And energy-saving lamps may flicker or glow faintly in the dark. Let us consider in detail the advantages and disadvantages of each of the schemes.
Switch illumination circuit based on LED and resistance
Currently, lighting switches are usually equipped with LEDs, which are included in the switch according to the electrical diagram below.
When the switch is in the “Off” position, the current passes through resistance R1, then through the LED VD2, which lights up. Diode VD1 protects VD2 from reverse voltage breakdown. R1 of any type with a power of more than 1 W, rated from 100 to 150 kOhm. With the R1 rating indicated on the diagram, the current flows about 3 mA, which is quite enough for a clearly visible glow in the dark. If the LED glow is insufficient, then the resistance value must be reduced. VD1 of any type, VD2 of any type and color of light. In order to understand the theory and independently calculate the size and power of the resistor, you need to read the article “The Law of Current Strength”.
An LED switch illumination circuit can be installed if the lamp uses incandescent light bulbs. If there are compact fluorescent (energy-saving) ones, then it is possible that in the dark you may notice their faint glow or blinking. If the lamp is equipped with LED bulbs, then the backlight made according to this scheme may not even work, since the resistance of the LED bulb is very high and a current of sufficient strength for the LED to glow may not be created. In the dark, the LED light may glow faintly. The scheme is very simple, but has a big drawback: it consumes a lot of electricity, about 1 kW×hour per month. This is what the assembled circuit looks like.
All that remains is to connect the ends that point down to the switch terminals. If you did not make any mistakes during installation, the circuit will work immediately. I specifically posted a photo of the twists for those who do not have the opportunity to solder the connections with a soldering iron. For reliability and safety, you still need to solder the twists and cover the bare wires and resistor with electrical tape.
Switch illumination circuit using an LED and a capacitor
To increase the efficiency of the backlight in the switch, you can install an additional capacitor in the electrical circuit, while reducing the value of resistor R1 to 100 Ohms.
This circuit differs from the above by using capacitor C1 as a current-limiting element instead of a resistor. R1 here performs the function of limiting the capacitor charge current. Resistance R1 can be used from 100 to 500 Ohms with a power of 0.25 W. Instead of a simple diode VD1, you can install an LED, the same as VD2. The efficiency of the circuit will not change, and both LEDs will shine at once with the same brightness.
The advantage of a circuit with a capacitor is low energy consumption, about 0.05 kW×hour per month. The disadvantages of the scheme are the same as those presented above and, in addition, large overall dimensions.
Switch illumination circuit for a neon light bulb (neon)
The backlighting circuit for a switch on a neon light bulb (neon) is devoid of the disadvantages inherent in the LED backlighting circuits presented above. This switch illumination scheme is suitable for chandelier switches and any other types of lamps, with both incandescent light bulbs and energy-saving fluorescent and LED lamps installed in them.
When the switch is open, current flows through resistance R1, the discharge lamp HG1 and it lights up. R1 of any type with a power of more than 0.25 W, rated from 0.5 to 1.0 MOhm.
In the photo you see the assembled switch illumination circuit, which couldn’t be simpler. It is enough to connect a resistor in series with a neon light bulb of any type and the circuit is ready.
Where to get a neon light bulb
Neon gas-discharge bulbs (neons) are presented in a wide range and you can use any of them available. Please note that on the left in the photo there is a gas-discharge light bulb with a 200 kOhm resistor, removed from a failed computer extension cord switch, which is also called the Pilot. It can be successfully installed in any switch without the additional hassle of finding components. The same light bulbs with a resistor are installed in electric kettles and other electrical appliances to indicate the on state. In the center of the photograph, a Small-sized Thyratron (triode) with a Cold Cathode MTX-90 unexpectedly appeared. To be fair, I’ll say that the MTX-90 thyratron has been shining in my sconce for decades.
Neon bulbs (neons) surround us almost everywhere. Are you surprised? All older fluorescent light fixtures use a starter, which is a real neon light bulb housed in a cylindrical housing. In order to remove it from the lamp body, you need to turn the cylinder slightly counterclockwise. There are as many starters as there are fluorescent lamps in a luminaire. In the starter, a capacitor is also connected in parallel to the neon lamp; it serves to suppress interference and is not needed in the manufacture of the indicator.
If the starter is taken from an old lamp, before using a neon bulb, do not be lazy to check it. Before installation, you must connect the light bulb according to the above diagram. It is better to take a neon from a new starter, since in old ones the glass of the bulb bulb from the inside is usually covered with a dark coating and the glow will be less visible. A light bulb from a starter can be successfully used to make your own phase indicator.
A ready-made lighting kit for installation in a wall switch can be taken from a faulty modern electric kettle. As a rule, most models have a water heating indicator. The indicator is a neon light bulb with a current-limiting resistor connected in series and this circuit is connected in parallel to the heating element. If you have a faulty electric kettle lying around in your household, then a neon light bulb with a resistor can be removed from it and mounted in the switch.
The photo shows three neon lights from electric kettles. As you can see, they shine quite brightly, so in the dark they will be visible in the switch from a great distance.
If you look closely at the insulating tubes placed at the junction of the terminals of the neon light bulb with the wires, you will notice a thickening on one of the tubes. A current-limiting resistor is located at this location. If you cut the tube lengthwise, a picture will open, as in this photo.
Step-by-step instructions for installing in a backlight switch
When working on the switch, you must turn off the power supply!
Neon light bulbs come with a base and without a base, in which the leads come directly from the glass bulb. Therefore, the method of their installation is somewhat different.
Installing a neon light bulb with flexible leads into a switch
As a rule, the length of the leads of a neon light bulb (neon) or LED is not enough for direct connection to the switch terminals and therefore they must be extended with a piece of copper wire. For these purposes, both single-core and stranded wire of any cross-section are suitable. The best way to connect the wire to the terminal is by soldering.
Before soldering, the terminals of the neon light bulb and the ends of the conductor must be cleaned of oxides and tinned with solder using a soldering iron. Then join to a length of at least 5 mm and solder.
Then the soldering point and the terminal of the neon light bulb need to be insulated by putting an insulating tube on them. You can simply wrap a couple of turns of insulating tape.
For ease of soldering, the end of the soldered conductor is formed into a ring using pliers and secured to the switch terminal.
The keys or covers of wall switches are usually made of white plastic and the light from a neon bulb (neon) or LED passes through them well. It is enough to make the switch key visible in the dark. Therefore, there is no need to drill a hole in the switch opposite the backlight installation location.
An insulating tube is also placed on the soldered resistor or it is insulated with insulating tape. The end of the output is formed into a ring and secured to the second terminal of the switch.
The switch illumination circuit is installed, the switch is connected to the electrical wiring, all that remains is to install the key and the work can be considered complete.
Installing a neon light bulb with a socket into a switch
It is not advisable to use a socket for illumination, since the service life of a neon light bulb (neon) is longer than the service life of the switch, and there is not enough space in the box. Therefore, it is more advisable to connect the base to the circuit using soldering.
To do this, you need to remove the insulation from the wires, tin the bare ends and make small loops. Then solder the light bulb terminals on the base to the soldering points.
A resistor is soldered to the wire extending from the central contact of the base at a distance of 2-3 cm. The resistor leads need to be shortened and wire loops made at the ends. A wire is also soldered to the second terminal of the resistor.
The threaded part of the base and the resistor must be insulated. This can be done using heat-shrinkable tubing, insulating tape, or the method I suggest.
Many good polyvinyl chloride (PVC) tubing is often used to insulate wires. To prevent the tube section (cambric) from slipping, the internal diameters should be slightly smaller than the insulated solder. There are always difficulties in finding a cambric of suitable diameter.
But if you hold the cambric for about 15 minutes in acetone, it becomes elastic and can be easily put on a part that is one and a half times larger than its internal diameter. This is how I insulated light bulbs in a homemade New Year's garland in the distant past.
After the acetone evaporates, the cambric again returns to its original size and tightly fits the lamp base. It is no longer possible to remove the cambric unless it is re-soaked with acetone. This insulation method is similar to heat-shrinkable tubing, but no heating is required.
After the preparatory work, the backlight is placed in the switch box and connected to its contacts.
If there is not enough space to place a resistor or you do not have the required power at hand, then the resistor can be replaced with several of lower power, connecting them in series or in parallel.
When resistors of the same resistance are connected in series, the power dissipated on one resistor will be equal to the calculated power divided by the number of resistors, and their value will decrease and will be equal to the calculated value divided by the number of resistors. For example, according to calculations, a resistor with a power of 1 watt and a nominal value of 100 kOhm is required. 1 kOhm = 1000 Ohm. This resistor can be replaced with two 0.5-watt, 50-kOhm resistors connected in series.
When connecting resistors of the same resistance in parallel, the power is calculated as with a series connection, and the value of each resistor must be equal to the calculated value multiplied by the number of resistors connected in parallel. For example, to replace one 100 kOhm resistor with three, the resistance of each must be 300 kOhm.
When installing the circuit, connect the resistor (capacitor) only to the phase wire of the switch. Since the currents flowing through the circuit elements do not exceed several milliamps, there are no special requirements for the quality of the contacts. If the box with the switch in which the backlight will be mounted is metal, then it is necessary to exclude the possibility of the current-carrying conductors touching its walls.
It is impossible to spoil anything when installing the backlight in a wall switch, since the lamp itself is a current limiter. The worst thing that can happen is the failure of the mounted elements if serious mistakes are made. For example, turn on the LED without a current-limiting resistor, or the resistor value is mistakenly taken to be 100 ohms instead of 100 kOhm.
Calculator for calculation
current limiting resistor parameters
When installing it yourself in a backlight switch on an LED or neon light bulb, it is necessary to determine the size and power of the current-limiting resistance. The calculation can be done using formulas, but it is much more convenient to calculate the resistor parameters using a special calculator. Just enter the parameters and get the finished result. The calculator can also be useful for selecting a resistor in a factory-made backlit switch in case the resistor fails.
Reference. On an LED the voltage drop is in the range of 1.5-2 V, on a neon bulb it drops 40-80 V. The required minimum current at which the LED is guaranteed to glow is 2 mA, for a neon bulb - 0.1 mA. This data can be used for calculations on a calculator if the parameters of an LED or neon bulb are unknown.
When choosing a resistance, it becomes necessary to determine its value by color marking. An online calculator will help solve this issue.
Illuminated switches for electrical appliances
Illuminated switches are often installed in switches on carriers and extension cords, heaters and other electrical appliances. They usually have a neon light bulb with resistors built into them. I once had to repair a Pilot type extension cord in which the switch control key fell out and cracked.
When I disassembled the switch, I did not find a current-limiting resistor, which I was very surprised by. Neon bulbs must not be connected to a 220 V electrical network without current limitation. It will fail immediately. On the left photo is a view of the key from the side where the neon light bulb is installed, and on the right, the reverse side of the same switch key.
I measured the resistance between the spring and the terminal of the neon light bulb, it was 150 kOhm. This switch used an interesting design solution: two 150 kOhm resistors were installed in the key holes and a spring pressed them to the terminals of the neon light bulb, ensuring reliable contact. The springs themselves exert pressure on the movable contacts in the switch, from which, when the switch is in the On position, power is supplied to the neon light bulb.
Using a backlight circuit for display
The backlight of the switch performs another additional useful function - it indicates the functionality of the switch and the serviceability of the light bulb. If the backlight works, but the light does not turn on, then the switch is faulty. If the backlight does not work, then the light bulb has burned out.
Any of the above presented circuit options can be used to indicate the health of devices or electrical circuits. For example, if you connect it in parallel with a fuse, then if it blows, the indicator will light up. If an electrical appliance does not have a standard on indicator, then by connecting the indicator immediately after the switch, you can always see whether the appliance is on. When installed in a socket (connected parallel to the current-carrying wires), you will know whether the socket is energized or not.
To find a switch by touch, while also being in an unfamiliar and unusual environment, you can spend a lot of time and nerves touching objects. Waking up in the dark and searching for the light switch poses the risk of tripping and injury.
Therefore, light indication of manual lighting control devices began to be used almost immediately after the mass distribution of electric lighting devices. At first, control devices for electric lighting devices in enterprises and public institutions were illuminated using different methods.
Later, household switches with backlight began to be produced, which did not differ from ordinary ones in size, installation method and connection.
Balanced backlight brightness
The convenience of backlit switches lies in the possibility quick definition location of the switching device thanks to the weak glow of the built-in light source.
The brightness of the glow should ensure that the switch is visible immediately to a person entering the room from the dark, and after some time necessary for the accommodation of an eye accustomed to the light. Obviously, the more powerful and brighter the light source, the more powerful and bright the light source, the more noticeable the indication, but too bright illumination in the dark will interfere with relaxation, and will also increase energy consumption.
Light switch indicator light In factories that manufacture electrical products, the glow power is selected and set in such a way as to meet the needs of the majority of consumers.
All electronic components necessary for the light indication are installed by the manufacturer during the manufacture of the product, so the installation and connection diagram of a backlit switch is identical to a similar switching device without backlighting, and the user does not need to delve into the operating principle of the indication.
Connection diagram for single-key switch with backlight But, to develop your own backlight for a switch or any other device, you need to understand the existing circuits, and you will also need to empirically determine the required brightness of the light source.
How the backlight works
In switches and other devices equipped with light indications, low-power neon glow discharge lamps and LEDs are used as a light source.
LEDs in the switch Regardless of the light sources used, the backlight is connected parallel to the switch contacts. In this case, the current, when the contacts are open, flows through the backlight elements and the filament of the lighting lamp.
Connection diagram of LED to switch If a fluorescent or LED lamp is used as an electric lighting device, then the current required for the backlight to operate flows through the electronic circuit of these electrical lighting devices, which is why they flicker unpleasantly in the dark.
After a detailed examination of the circuits and operating principles of the lighting elements, advice will be given on how to eliminate the described flickering effect of these electric lighting devices when they are controlled by backlit switches.
Analysis of a circuit with a neon light bulb
The key parameter when calculating neon light bulb connection circuits is the maximum permissible current, which in the power circuit of the indication light source is limited by a current-limiting resistor connected in series, thereby achieving a voltage drop to the nominal operating level.
In this neon light bulb wiring diagram, the resistance value varies depending on the type of electrical appliance used for lighting. When using incandescent lamps with relatively low resistance, the resistor value is chosen close to the maximum.
For fluorescent and LED lighting devices, the resistor resistance is reduced, but not below the specified limit in the diagram.
LED backlight circuit
When connecting an LED, the same principle of current limitation is observed, but this semiconductor device only works when connected directly. With a negative half-wave of alternating voltage, breakdown of the LED may occur.
Therefore, to avoid breakdown, an additional diode is used in the circuit, connecting it in parallel or in series with the LED.
In this circuit, a parallel-connected diode in the reverse direction extinguishes the negative half-wave, shunting the LED, passing current through itself. The power dissipation of the diode must be at least 1W. Obviously, the energy of the negative half-wave voltage is spent on heating the diode and resistor.
Here, a series-connected LED does not transmit the negative half-wave, thereby protecting the LED. This scheme is more economical, but the flickering of the LED will be more noticeable, and the brightness will decrease due to the nonlinearity of the frequency response of semiconductor devices.
Connecting 2 LEDs back to back
To increase the efficiency of electricity use, you can turn on two LEDs back-to-back - in parallel, that is, each LED will operate at its own half-wave. Here, the voltage drop of the working LED will limit the breakdown voltage for the reverse-connected analogue.
A capacitor can be used as a current limiter, in which the reactance to alternating current decreases as the capacitance increases.
Practical calculations and installation
Of course, it is not profitable to develop and install circuits with LEDs when ready-made switches for sale with backlight, practically no different in price from ordinary ones, and do not require any additional manipulations.
But you can make your own backlight for the input panel, based on a fairly powerful LED that turns on when the lid is opened. In a similar way, any device can be equipped with a light indication. To independently develop a backlight, in order to select the resistor value and its power dissipation, you need to use the formula.
When installing LEDs, it is necessary to maintain the polarity of their terminals, which are called anode and cathode.
Designation on LED circuits The LED glows with direct current, which occurs when the anode is connected to the plus (positive half-wave of alternating voltage), and the cathode to the minus.
Therefore, the anode of an LED is often marked with a “+” sign. Since the diode and LED are semiconductor devices, they are sensitive to overheating, so they should be soldered with care.
Eliminating the flickering effect of fluorescent and LED lamps
It must be remembered that the parameters of the backlight elements do not in any way affect the operation of the switched-on lighting lamp, since the circuit with the LED is shunted by the contacts of the switch, so practically no current flows through this circuit, and the indication does not work.
When the switch is turned off, the backlight current cannot noticeably heat the lamp filament, but it recharges the capacitors in the power supplies of fluorescent and LED lighting devices, which is why they periodically flash.
Exists several ways solutions to this problem:
- Refuse the backlit switch, or turn off the luminous element;
- Connect zero to the switch and redo the circuit by powering the backlight from the neutral wire, bypassing the electrical lighting fixture. It makes sense to do this modernization when repairing electrical wiring, and if a wire of a smaller cross-section is used, the fuse must be turned on in series;
- Bypassing a fluorescent or LED lamp using a 200-300 kOhm, 1 W resistor, or a circuit with a capacitor installed in the base socket, connected in parallel to the terminals.
Inside, HID neon lamps are filled with neon at low pressure, which emits an orange-red glow. The contents may include other inert gases. So in three words you can explain the principle of operation of neon lamps.
The editors of the publication today reveal all the nuances of the operation of neon lamps - from their characteristics and scope of application to quality testing.
Where is it better to use neon lamps?
- The working principle of a neon lamp
A neon lamp is a type of gas-discharge lamp, only with a neon glow.
The main element of a neon lamp is a glass tube with a metal electrode at each end. They are connected to the base, and the lamp itself is connected to the network through a socket. The neon lamp operates from a direct and alternating current source.
They are selected according to the network voltage (127 - 220 V), according to the voltage when an electric discharge occurs (60 - 550 V), according to the maximum permissible current (from 0.2 - 30 Ma).
Neon lamp 220V BA9S EKF The service life of neon lamps is long - 100-1000 hours.
Neon lamps today are represented not only by light bulbs, but also by strips (flexible neon) 12 Volt - LED garland, sealed in a PVC tube. Ribbons can be monotonous or multi-colored.
Neon lamps are characterized by durability and reliability. They are suitable for home, apartment, and for lighting larger rooms. They are actively used in computers, as an indication element or in the form of lighting - home or automotive, for outdoor advertising.
Application area of cold neon:
- car tuning;
- decorative lighting of interiors;
- production of illuminated letters, signs, signatures;
- festive illumination;
- illumination of shop windows, buildings, bridges, theater posters;
- design of casinos, night clubs, restaurants;
- landscape design.
Neon lamps review:
Connecting a neon lamp
Neon lamps remain relatively cold during operation, since they do not heat up more than 70-80°C.
Pros of neon lamps
- service life from 80,000 hours;
- catchy lighting effect;
- fire safety, since the device does not heat up;
- quiet operation;
- control the brightness of the gas light lamp and select the desired shade of white light.
Cons of neon lamps
- fragility;
- content of harmful substances;
- high voltage in the network and a high-voltage transformer are required;
- high price.
Each inert gas and metal vapor has an exceptional spectrum (composition) of light.
IMPORTANT! Different shades of glow are obtained by mixing inert gases or applying phosphors to the surface of the discharge tube.
During the connection process:
- the transformer is selected according to the length of the lamp and the composition of the gas mixture, the secondary (output) voltage of the transformer is calculated from the tables;
- if there is no indication in the accompanying documents, electronic voltage converters are more suitable for enclosed spaces;
- Grounding is mandatory when installing neon lamps on the street;
- select a high-voltage PMVC wire of the required cross-section and length: the length of the wire should be minimal; PVC pipes are used to separate the wire from the metal parts of the structure;
- the neon lamp is installed in polycarbonate holders, according to the diagram indicated on the transformer, and the wire connections are insulated with tape and special tubes;
- all conductive parts of the structure must be grounded;
- since ordinary glass is used in the manufacture of neon lamps, it is necessary to use protective coatings made of plexiglass or polycarbonate;
- It is necessary to follow safety rules during installation: do not drop or shake the neon lamp - the structure must not depressurize, otherwise the neon lamp will not light;
- To make the glow different colors, mercury vapor and a phosphor are added inside.
| View | Average burning time | Operating current |
|---|---|---|
| TN- 0.2 | at least 220 hours | no more than 0.2 mA |
| TN- 0.3 | at least 220 hours | no more than 0.3 mA |
| TN- 0.5 | at least 300 hours | no more than 0.5 mA |
| TN- 0.9 | at least 300 hours | no more than 0.9 mA |
| TN-1 | at least 100 hours | no more than 1.0 mA |
| TN-20 | at least 1000 hours | no more than 20 mA |
| TN-30 | at least 1000 hours | no more than 30 mA |
The table shows glow discharge gas-light lamps. They are used as light signals in radio engineering and electrical devices.
IMPORTANT! In the lamp type designation, the letter “T” directly means “smoldering” (type of discharge), the letter “N” means “neon” (name of the gas filler), the indicated numbers are the maximum operating current in milliamps.
Main characteristics of all neon lamps:
- outside diameter;
- linear length;
- color;
- color rendering index;
- luminous flux at current 50 mA and 80 mA;
- power consumption at current 50 mA and 80 mA;
- electrical length.
Indicator lamps
Luminescent
Signal
Decorative
The color of the glow in neon lamps depends entirely on the composition of the gas. Orange-red is most characteristic of indicator lamps.
IMPORTANT! The household candle lamp is suitable for antique decorative lamps.
A fluorescent lamp is a daylight electrical device mounted in specially designed luminaires. The downside is that they burn out very often.
Fluorescent lamp PHILIPS TL-D90 De Luxe Signal neon lamps are devices designed for light indication of electrical signals. The design consists of two electrodes in the form of cylinders, disks or rods of various configurations, placed in a glass container. The pressurized cylinder contains a neon mixture, which produces a red glow, or a neon-helium mixture, which produces an orange-red glow.
Neon lamp Camelion LH26-3U Blacklight E27 Decorative neon lamps are designed for installation in a regular standard E14 or E27 socket and operate on a voltage of 220 V. They contain a built-in ballast resistor, which makes it possible to connect them directly to the lighting network.
A green fluorescent lamp is used as a signal light source. The inside of the glass flask is coated with a special fluorescent substance, which absorbs red light and turns it green.
Fluorescent lamp T8 special. — Narva 18W / T8 / 019 Small neon lamps are used as backlight, along with an LED paired with a resistance element. As a rule, they are powered in parallel with the main contacts of the switch.
IMPORTANT! If the switch is in the non-working position, the LED is powered through a filament inside the lamp with low resistance.
How to check the serviceability of neon lamps?
Inspection of gas-light signal neon lamps consists of their visual inspection and testing under voltage.
You can also check the functionality of a neon lamp by connecting it to a radio broadcast network using a low-frequency transformer.
In the absence of networks - radio broadcasting and alternating current - you can check using batteries and a low-frequency transformer (power or inter-lamp).
The fluorescent lamp is started using ballasts (electromagnetic or electronic). In modern lamps, electronic ballasts (electronic ballasts) are more often used.
To check the lamp, a working device with the same parameters is considered and connected in series according to the diagram to the lamp being tested. If the lamp works normally, then the cause of the malfunction is in the unit.
Features of different types of neon lamps
- Signal neon lamp
They are safety factors, adjusting the operation of transport systems. Signal neon lamps also include indicator lamps, which are actively used in devices and equipment for various purposes and serve as a source of information about the operation of the device.
- Fluorescent neon lamp
They are used successfully for lighting and irradiation of school, children's, residential and administrative premises, especially if natural lighting is insufficient. Manufacturers produce special lamps aimed at obtaining “sunbathing”.
Advantages of fluorescent lamps:
- provide a lot of light;
- increase performance;
- preserve vision;
- reduce fatigue;
- affect mood improvement.
IMPORTANT! If the spirals of a fluorescent lamp fail, how to light the lamp? This can be done without a voltage multiplier using a conventional electronic ballast circuit.
- Decorative neon lamp
Widely used in the design of various interiors.
How to start and how does a burnt out fluorescent lamp work?
Producing LED light bulbs is not cheap. In terms of optimal price/quality ratio, the undisputed leaders are Russia, China, and Japan.
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A neon lamp belongs to the class of glow discharge devices. It is a glass cylinder (Fig. 1), inside of which two metal electrodes are placed. Electrodes can be flat, cylindrical, or in the form of straight or curved rods. The cylinder is filled with an inert gas (neon, argon or a mixture of them with helium) under low pressure (several mm of mercury).
Rice. 1
One of the lamp electrodes is the cathode, the other is the anode. For lamps designed to operate on alternating current, each electrode is alternately an anode and a cathode.
Let's assemble a simple installation in accordance with the diagram shown in Fig. 2, from a power source, potentiometer R1 and a voltmeter with a measurement limit of 150 V, connected in parallel with the neon lamp L1.
Rice. 2
As a power source, you can use a battery or a low-power rectifier that provides a constant voltage of at least 80 V.
While the voltage on the lamp electrodes is low, the gas gap between the electrodes is an insulator. As the potentiometer slider moves to the left (according to the diagram), the voltage on the lamp electrodes gradually increases. At a certain voltage for a given lamp, a glow discharge occurs in it, while the internal resistance of the lamp sharply decreases, and the current through it increases. The voltage at which a glow discharge occurs in the lamp is called the ignition voltage. Its value depends on the composition and pressure of the gas in the lamp, the material and shape of the electrodes, and the distance between the electrodes.
The occurrence of a glow discharge can be explained as follows. In a gas, even at ordinary temperatures, some of the molecules will be ionized, that is, in the gas, among the neutral molecules, there will be electrons and positive ions - gas molecules that have lost some of their electrons.
When a constant voltage is applied to the electrodes of the lamp, an electric field is created between them. Electrons move in this field to the positive electrode - the anode, and positive ions move to the negative electrode - the cathode. If the electric field strength between the electrodes of the lamp is high enough, the electrons acquire such a speed that when they collide with a gas molecule, they ionize it; in turn, the nones, bombarding the cathode, knock out new electrons from it. As a result of ionization, the gas becomes electrically conductive, but unlike metals, where the current is created by electrons, here both electrons and ions participate in creating the current.
Due to the fact that gas molecules, both during ionization and during recombination (reduction of an ion into a neutral molecule as a result of electron capture) can emit light, the gas near the cathode begins to glow. The color of the glow can be red or red-orange depending on the composition of the gas.
When alternating current passes through a neon lamp, a glow is observed at both electrodes.
The glow area depends on the current through the lamp. As the current increases, more and more sections of the cathode are switched on and the glow area expands. The voltage at the lamp electrodes remains almost constant until the entire cathode is illuminated.
Neon lamp - indicator of body electrification. You can determine whether a body is charged not only with an electrometer, but also with a neon lamp. When the electrode terminal of a neon lamp approaches an electrified body, for example, a glass or ebonite rod electrified by friction, a glow discharge occurs in the lamp. The lamp should be held by the terminal of the second electrode.
Using a neon lamp, you can make sure that during operation of the school electrophore machine, only sectors of aluminum powder applied to the disks are electrified - to do this, you should bring the lamp to the sector of the disk. If the lamp is brought close to the disk between the sectors, the lamp will not light up.
Neon lamp - polarity indicator. Taking advantage of the fact that the glow occurs at the cathode, that is, the electrode at a negative potential, you can use a neon lamp to determine the polarity of a direct current source. To do this, connect the lamp to the terminals of the current source and determine which electrode of the lamp lights up.
First, when connecting a neon lamp to a direct current source whose polarity is known, you need to establish exactly how the lamp electrodes are connected to the base.
Neon lamp - phase wire indicator. Two electrical wires are brought into the apartment. One of them is connected to ground, it is called the neutral wire. It is safe to touch. The other wire, called the phase wire, is at full voltage relative to ground and touching it can be life-threatening. You can distinguish these wires from one another using a probe with a neon lamp (Fig. 3).
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The probe can be mounted in a screwdriver handle made of transparent plastic, while one electrode of the lamp is connected to the screwdriver blade through resistor R1, and the other electrode is connected to a metal ring placed on the screwdriver handle.
Touching the neutral wire with the blade of a screwdriver does not cause the lamp to ignite; if you touch the phase wire, the lamp will light up. The screwdriver should be held so that contact is ensured between the hand and the metal ring.
Neon lamp - fuse blown indicator. When a fuse, the “plug,” blows, you have to unscrew all the fuses one by one from their sockets in search of the blown one. If you turn on a neon lamp and resistor R1 in parallel with each fuse (Fig. 4), then when the fuse blows, the mains voltage through the switched-on electrical appliances and resistor R1 will be applied to the neon lamp, causing it to ignite.
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Neon lamp - mains voltage indicator. During the day, the voltage of the electrical network usually varies within certain limits. In the evening, when the total number of electrical appliances connected to the network increases, the voltage drops slightly. During the day, when the network load is low, the voltage becomes normal or slightly higher than normal.
For some devices, for example, a TV or radio, the change in mains voltage should not exceed certain values in order to avoid their failure. You can monitor the network voltage using a voltmeter, but it is better to do this using a voltage indicator made on neon lamps.
The indicator diagram is shown in Fig. 5.
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An AC network with a voltage of 220 V includes two voltage dividers consisting of resistors R1, R2 and R3, R4. Neon lamps L1 and L2 of type MH-3 are connected in parallel with resistors R1 and R3. The resistances of resistors R1 and R2 are selected so that the voltage drop across resistor R1 is sufficient to ignite lamp L1 when the network voltage is equal to the minimum permissible (200 V). The voltage drop across resistor R3 should be equal to the ignition voltage of lamp L2 when the network voltage increases to the maximum permissible (230 V).
Consequently, if the mains voltage is within acceptable limits, one lamp L1 lights up. If none of the lamps is lit, it means that the network voltage is insufficient for normal operation of the TV, while the burning of both lamps indicates an increase in voltage above the established limits, in both cases the TV must be disconnected from the network.
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