Schemes for switching on fluorescent lamps without a starter. Operating principle and connection diagram of a fluorescent lamp

The switching circuit for fluorescent lamps is much more complex than that of incandescent lamps.
Their ignition requires the presence of special starting devices, and the life of the lamp depends on the quality of these devices.

To understand how launch systems work, you must first become familiar with the design of the lighting device itself.

A fluorescent lamp is a gas-discharge light source, the luminous flux of which is formed mainly due to the glow of a phosphor layer applied to the inner surface of the bulb.

When the lamp is turned on, an electronic discharge occurs in the mercury vapor that fills the test tube and the resulting UV radiation affects the phosphor coating. With all this, the frequencies of invisible UV radiation (185 and 253.7 nm) are converted into visible light radiation.
These lamps have low energy consumption and are very popular, especially in industrial premises.

Scheme

When connecting fluorescent lamps, a special starting and regulating technique is used - ballasts. There are 2 types of ballasts: electronic - electronic ballast (electronic ballast) and electromagnetic - electromagnetic ballast (starter and choke).

Connection diagram using electromagnetic ballast or electronic ballast (throttle and starter)

A more common connection diagram for a fluorescent lamp is using an electromagnetic amplifier. This starter circuit.

Operating principle: when the power supply is connected, a discharge appears in the starter and
the bimetallic electrodes are short-circuited, after which the current in the circuit of the electrodes and the starter is limited only by the internal resistance of the inductor, as a result of which the operating current in the lamp increases almost three times and the electrodes of the fluorescent lamp instantly heat up.
At the same time, the bimetallic contacts of the starter cool down and the circuit opens.
At the same time, the choke breaks, thanks to self-induction, creates a triggering high-voltage pulse (up to 1 kV), which leads to a discharge in the gas environment and the lamp lights up. After which the voltage on it will become equal to half of the mains voltage, which will not be enough to re-close the starter electrodes.
When the lamp is on, the starter will not participate in the operating circuit and its contacts will and will remain open.

Main disadvantages

Compared to a circuit with electronic ballast, electricity consumption is 10-15% higher.

Long start-up of at least 1 to 3 seconds (depending on lamp wear)

Inoperability at low ambient temperatures. For example, in winter in an unheated garage.

The stroboscopic result of a flashing lamp, which has a bad effect on vision, and the parts of machine tools rotating synchronously with the mains frequency appear motionless.

The sound of the throttle plates humming, growing over time.

Switching diagram with two lamps but one choke. It should be noted that the inductance of the inductor must be sufficient for the power of these two lamps.
It should be noted that in a sequential circuit for connecting two lamps, 127 Volt starters are used; they will not work in a single-lamp circuit, which will require 220 Volt starters

This circuit, where, as you can see, there is no starter or throttle, can be used if the filaments of the lamps have burned out. In this case, the LDS can be ignited using step-up transformer T1 and capacitor C1, which will limit the current flowing through the lamp from a 220-volt network.

This circuit is suitable for the same lamps whose filaments have burned out, but here there is no need for a step-up transformer, which clearly simplifies the design of the device

But such a circuit using a diode rectifier bridge eliminates the flickering of the lamp at the mains frequency, which becomes very noticeable as it ages.

or more difficult

If the starter in your lamp has failed or the lamp is constantly blinking (along with the starter if you look closely under the starter housing) and there is nothing at hand to replace it, you can light the lamp without it - enough for 1-2 seconds. short-circuit the starter contacts or install button S2 (caution of dangerous voltage)

the same case, but for a lamp with a burnt-out filament

Connection diagram using electronic ballast or electronic ballast

An electronic ballast (EPG), unlike an electromagnetic one, supplies the lamps with a high-frequency voltage from 25 to 133 kHz rather than the mains frequency. And this completely eliminates the possibility of lamp flickering noticeable to the eye. The electronic ballast uses a self-oscillator circuit, which includes a transformer and an output stage using transistors.

Widely used fluorescent lamps are not without drawbacks: during their operation, the buzzing of the choke can be heard, the power system has a starter that is unreliable in operation, and most importantly, the lamp has a filament that can burn out, which is why the lamp has to be replaced with a new one.

The fluorescent lamp becomes “eternal”

Shown here is a diagram that eliminates these shortcomings. There is no usual buzzing, the lamp lights up instantly, there is no unreliable starter, and, most importantly, you can use a lamp with a burnt-out filament.

Capacitors C1, C4 must be paper, with an operating voltage of 1.5 times the supply voltage. It is advisable for capacitors C2, C3 to be mica.

Resistor R1 is necessarily a wire-wound one; its resistance depends on the power of the lamp.

Data for circuit elements depending on the power of fluorescent lamps are given in the table:

Diodes D2, D3 and capacitors C1, C4 represent a full-wave rectifier with doubling the voltage. The values of capacitances C1, C4 determine the operating voltage of lamp L1 (the larger the capacitance, the greater the voltage on the electrodes of lamp L1). At the moment of switching on, the voltage at points a and b reaches 600 V, which is applied to the electrodes of lamp L1. At the moment of ignition of lamp L1, the voltage at points a and b decreases and ensures normal operation of lamp L1, designed for a voltage of 220 V.

The use of diodes D1, D4 and capacitors C2, C3 increases the voltage to 900 V, which ensures reliable ignition of lamp L1 at the moment of switching on. Capacitors C2, C3 simultaneously help suppress radio interference.

Lamp L1 can work without D1, D4, C2, C3, but in this case the reliability of inclusion decreases.

Fluorescent lamps have long been firmly established in our lives, and are now gaining the greatest popularity, since electricity is constantly becoming more expensive and the use of conventional incandescent lamps is becoming quite an expensive pleasure. But not everyone can afford energy-saving compact lamps, and modern chandeliers require a large number of them, which calls into question cost savings. That is why more and more fluorescent lamps are being installed in modern apartments.

The device of fluorescent lamps

To understand how a fluorescent lamp works, you should study its structure a little. The lamp consists of a thin cylindrical glass bulb, which can have different diameters and shapes.

Lamps can be:

straight;
ring;
U-shaped;
compact (with base E14 and E27).

Although they all differ in appearance, they have one thing in common: they all have electrodes inside, a luminescent coating and an injected inert gas containing mercury vapor. The electrodes are small spirals that heat up for a short period of time and ignite the gas, due to which the phosphor applied to the walls of the lamp begins to glow. Since ignition coils are small in size, the standard voltage available in the home electrical network is not suitable for them. For this purpose, special devices are used - chokes, which limit the current strength to the nominal value, thanks to inductive reactance. Also, so that the spiral heats up briefly and does not burn out, another element is used - a starter, which, after igniting the gas in the lamp tubes, turns off the filament of the electrodes.

Throttle

Starter

Operating principle of a fluorescent lamp

A 220V voltage is supplied to the terminals of the assembled circuit, which passes through the inductor to the first spiral of the lamp, then goes to the starter, which fires and passes current to the second spiral connected to the network terminal. This is clearly seen in the diagram below:

Often a capacitor is installed at the input terminals, playing the role of a surge filter. It is through its operation that part of the reactive power generated by the inductor is extinguished, and the lamp consumes less electricity.

How to connect a fluorescent lamp?

The connection diagram for fluorescent lamps given above is the simplest and is intended for igniting one lamp. In order to connect two fluorescent lamps, you need to slightly change the circuit, following the same principle of connecting all elements in series, as shown below:

In this case, two starters are used, one for each lamp. When connecting two lamps to one choke, you should take into account its rated power, which is indicated on its body. For example, if it has a power of 40 W, then you can connect two identical lamps with a load of no more than 20 W to it.

There is also a diagram for connecting a fluorescent lamp without using starters. Thanks to the use of electronic ballast devices, lamps are ignited instantly, without the characteristic “blinking” of starter control circuits.

Electronic ballasts

Connecting a lamp to such devices is very simple: detailed information is written on their body and it is schematically shown which contacts of the lamp need to be connected to the corresponding terminals. But to make it completely clear how to connect a fluorescent lamp to an electronic ballast, you need to look at a simple diagram:

The advantage of this connection is the absence of additional elements required for starter lamp control circuits. In addition, by simplifying the circuit, the reliability of the lamp operation increases, since additional connections of wires to starters, which are also rather unreliable devices, are eliminated.

Below is a diagram of connecting two fluorescent lamps to the electronic ballast.

As a rule, the electronic ballast device already comes with all the necessary wires for assembling the circuit, so there is no need to invent something and incur additional costs to purchase the missing elements.

How to check a fluorescent lamp?

If the lamp stops lighting, then the likely cause of its malfunction may be a break in the tungsten filament, which heats the gas, causing the phosphor to glow. During operation, tungsten gradually evaporates, settling on the walls of the lamp. At the same time, a dark coating appears on the edges of the glass bulb, warning that the lamp may soon fail.

How to check the integrity of a tungsten filament? It’s very simple, you need to take a regular tester with which you can measure the resistance of the conductor and touch the lead ends of the lamp with the probes.

The device shows a resistance of 9.9 ohms, which eloquently tells us that the thread is intact.

When checking the second pair of electrodes, the tester shows a complete zero; this side has a broken filament and therefore the lamp does not want to light up.

The break of the spiral occurs because over time the thread becomes thinner and the tension passing through it gradually increases. Due to the increase in voltage, the starter fails - this can be seen from the characteristic “blinking” of the lamps. After replacing burnt out lamps and starters, the circuit should work without adjustment.

If turning on the fluorescent lamps is accompanied by extraneous sounds or a burning smell is heard, you should immediately turn off the power to the lamp and check the functionality of all its elements. There is a possibility that there is slack in the terminal connections and the wire connection is heating up. In addition, the inductor, if made poorly, may have a turn short circuit in the windings and, as a result, failure of the fluorescent lamps.

The fluorescent lamp was invented in the 1930s as a light source and became famous and widespread in the late 1950s.

Its advantages are undeniable:

Durability.
Maintainability
Economical.
Warm, cold and colored shade of glow.

A long service life is ensured by a properly designed start-up and operation control device by the developers.

Industrial fluorescent lamp

LDS (fluorescent lamp) is much more economical than a conventional incandescent light bulb, however, an LED device of similar power is superior to a fluorescent one in this indicator.

Over time, the lamp stops starting, blinks, “buzzes”, in a word, does not return to normal mode. Staying and working indoors becomes dangerous to a person’s vision.

To correct the situation, they try to turn on a known good LDS.

If a simple replacement does not produce positive results, a person who does not know how a fluorescent lamp works comes to a dead end: “What to do next?” We will look at what spare parts to buy in the article.

Briefly about the features of the lamp

LDS refers to gas-discharge light sources of low internal pressure.

The operating principle is as follows: the sealed glass case of the device is filled with inert gas and mercury vapor, the pressure of which is low. The inner walls of the flask are coated with phosphor. Under the influence of an electrical discharge occurring between the electrodes, the mercury composition of the gas begins to glow, generating ultraviolet radiation invisible to the eye. It, having an effect on the phosphor, causes a glow in the visible range. By changing the active composition of the phosphor, cold or warm white and colored light is obtained.

Operating principle of LDS

Expert opinion

Alexey Bartosh

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Bactericidal devices are designed in the same way as LDS, but the inner surface of the flask, made of quartz sand, is not coated with a phosphor. Ultraviolet light is emitted unhindered into the surrounding space.

Connection using electromagnetic ballast or electronic ballast

The structural features do not allow connecting the LDS directly to a 220 V network - operation from this voltage level is impossible. To start, a voltage of at least 600V is required.

Using electronic circuits, it is necessary to provide the required operating modes one after another, each of which requires a certain voltage level.

Operating modes:

ignition;
glow.

Triggering involves applying high voltage pulses (up to 1 kV) to the electrodes, causing a discharge to occur between them.

Certain types of ballasts, before starting, heat the spiral of electrodes. Incandescence makes it easier to start the discharge, while the filament overheats less and lasts longer.

After the lamp lights up, power is supplied by alternating voltage, and the energy-saving mode is activated.

Connection using electronic ballasts

connection diagram

In devices produced by industry, two types of ballasts (ballasts) are used:

electromagnetic ballast control device EmPRA;
electronic ballast - electronic ballast.

The diagrams provide for various connections, they are presented below.

Scheme with electronic ballasts

Connection using electronic ballasts

The electrical circuit of a luminaire with electromagnetic ballasts (EMP) includes the following elements:

throttle;
starter;
compensation capacitor;
Fluorescent Lamp.

connection diagram

When power is supplied through the circuit: throttle – LDS electrodes, voltage appears at the starter contacts.

The bimetallic contacts of the starter, located in a gaseous environment, heat up and close. Because of this, a closed circuit is created in the lamp circuit: 220 V contact – choke – starter electrodes – lamp electrodes – 220 V contact.

The electrode threads, when heated, emit electrons, which create a glow discharge. Part of the current begins to flow through the circuit: 220V – choke – 1st electrode – 2nd electrode – 220V. The current in the starter drops, the bimetallic contacts open. According to the laws of physics, at this moment a self-inductive emf appears at the inductor contacts, which leads to the appearance of a high-voltage pulse at the electrodes. A breakdown of the gaseous medium occurs, and an electric arc occurs between opposite electrodes. The LDS begins to glow with an even light.

Subsequently, a choke connected in line ensures a low level of current flowing through the electrodes.

A choke connected to an alternating current circuit acts as an inductive reactance, reducing the efficiency of the lamp by up to 30%.

Attention! In order to reduce energy losses, a compensating capacitor is included in the circuit; without it, the lamp will work, but power consumption will increase.

Circuit with electronic ballasts

Attention! In retail, electronic ballasts are often found under the name electronic ballast. Sellers use the name driver to designate power supplies for LED strips.

Appearance and design of electronic ballasts

Appearance and design of an electronic ballast designed to turn on two lamps with a power of 36 watts each.

Expert opinion

Alexey Bartosh

Specialist in repair and maintenance of electrical equipment and industrial electronics.

Ask a question to an expert

Important! It is forbidden to turn on electronic ballasts without a load in the form of fluorescent lamps. If the device is designed to connect two LDS, it cannot be used in a circuit with one.

In circuits with electronic ballasts, the physical processes remain the same. Some models provide pre-heating of the electrodes, which increases the life of the lamp.

Electronic ballast type

The figure shows the appearance of electronic ballasts for devices of different power levels.

The dimensions allow the electronic ballast to be placed even in an E27 base.

Electronic ballasts in the base of an energy-saving lamp

Compact ESLs - one of the types of fluorescent ones - can have a g23 base.

Table lamp with G23 base

Functional diagram of electronic ballasts

The figure shows a simplified functional diagram of electronic ballasts.

Circuit for connecting two lamps in series

There are lamps that are designed to connect two lamps.

In case of replacement of parts, assembly is carried out according to schemes that are different for electronic ballasts and electronic ballasts.

Attention! Schematic diagrams of ballasts are designed to operate with a certain load power. This indicator is always available in product passports. If you connect lamps of a higher rating, the inductor or ballast may burn out.

Connection diagram for two lamps with one choke

If the device body has the inscription 2X18, the ballast is designed to connect two lamps with a power of 18 watts each. 1X36 - such a choke or ballast is capable of turning on one LDS with a power of 36 W.

In cases where a choke is used, the lamps must be connected in series.

Two starters will start their glow. These parts are connected in parallel with the LDS.

Connection without starter

The electronic ballast circuit does not initially include a starter.

Button instead of starter

However, in circuits with a choke you can do without it. A spring-loaded switch connected in series - in other words, a button - will help you assemble a working circuit. Briefly turning on and releasing the button will provide a connection similar in effect to the starter.

Important! This starterless option will turn on only with intact filaments.

The throttleless option, which also lacks a starter, can be implemented in different ways. One of them is shown below.

Luminescent What to do if a fluorescent lamp breaks

A fluorescent lamp is a light source where the glow is achieved by creating an electrical discharge in an environment of inert gas and mercury vapor. As a result of the reaction, an ultraviolet glow, invisible to the eye, appears, affecting the phosphor layer located on the inner surface of the glass bulb. The standard connection diagram for a fluorescent lamp is a device with an electromagnetic balance (EMB).

The device of fluorescent lamps

In most light bulbs, the bulb is shaped like a cylinder. More complex geometric shapes are found. At the ends of the lamp there are electrodes, reminiscent in design of the spirals of incandescent light bulbs. The electrodes are made of tungsten and soldered to the pins located on the outside. Voltage is applied to these pins.

A gas environment is created inside the fluorescent lamp, which is characterized by negative resistance, which manifests itself when the voltage between the electrodes located opposite each other decreases.

The lamp switching circuit uses a choke (ballast). Its task is to generate a significant voltage pulse, due to which the light bulb will turn on. The kit includes a starter, which is a glow discharge lamp with a pair of electrodes in an inert gas environment. One of the electrodes is a bimetallic plate. When turned off, the electrodes of the fluorescent light bulb are open.

The figure below shows a diagram of the operation of a fluorescent lamp.

How does a fluorescent lamp work?

The operating principles of fluorescent light sources are based on the following principles:

Voltage is sent to the circuit. However, at first the current does not reach the light bulb due to the high voltage of the environment. The current moves through the spirals of the diodes, gradually heating them. The current is supplied to the starter, where the voltage is sufficient to produce a glow discharge.
As a result of the heating of the starter contacts by the current, the bimetallic plate shorts. The metal takes on the functions of a conductor, and the discharge ends.
The temperature in the bimetallic conductor drops, and the contact in the network opens. The inductor creates a high voltage pulse as a result of self-induction. As a result, the fluorescent light bulb lights up.
A current flows through the lighting fixture, which is halved as the voltage across the inductor is reduced. It is not enough to start the starter again, the contacts of which are open when the light is on.

To create a circuit for switching on two light bulbs installed in one lighting fixture, you need a common choke. The lamps are connected in series, but each light source has a parallel starter.

Connection options

Let's consider different options for connecting a fluorescent lamp.

Connection using electromagnetic balance (EMB)

The most common type of connection for a fluorescent light source is a circuit with a starter, where electronic ballasts are used. The principle of operation of the circuit is based on the fact that as a result of connecting the power, a discharge occurs in the starter and the bimetallic electrodes are short-circuited.

The current in the electrical circuit of the conductors and the starter is limited only by the internal choke resistance. As a result, the operating current in the light bulb increases almost threefold, the electrodes rapidly heat up, and after the conductors lose temperature, self-induction occurs and the lamp ignites.

Disadvantages of the scheme:

Compared to other methods, this is a rather expensive option in terms of energy consumption.
Start-up takes at least 1 – 3 seconds (depending on the degree of wear of the light source).
Inability to work at low air temperatures (for example, in an unheated basement or garage).
There is a stroboscopic effect of flashing the light bulb. This factor negatively affects human vision. Such lighting cannot be used for production purposes, because fast moving objects (for example, a workpiece in a lathe) appear motionless.
Unpleasant humming of the throttle plates. As the device wears out, the sound increases.

The switching circuit is designed in such a way that it has one choke for two light bulbs. The inductance of the inductor should be enough for both light sources. 127 volt starters are used. They are not suitable for a single-lamp circuit; 220 Volt devices are needed there.

The picture below shows a chokeless connection. The starter is missing. The circuit is used in case of burnout of filament lamps. A step-up transformer T1 and a capacitor C1 are used, which limits the current flowing through the light bulb from a 220-volt network.

The following circuit is used for light bulbs with burnt out filaments. However, there is no need for a step-up transformer, making the design of the device simpler.

Below is shown a method of using a diode rectifier bridge, which eliminates the flickering of a light bulb.

The figure below shows the same technique, but in a more complex design.

Two tubes and two chokes

To connect a fluorescent lamp, you can use a serial connection:

The phase from the wiring is sent to the inductor input.
From the inductor output, the phase goes to the contact of the light source (1). From the second contact it is sent to the starter (1).
From the starter (1) it goes to the second contact pair of the same light bulb (1). The remaining contact is connected to zero (N).

Connect the second tube in the same way. First the inductor, then one contact of the light bulb (2). The second contact of the group is sent to the second starter. The starter output is combined with the second pair of light source contacts (2). The remaining contact should be connected to input zero.

Connection diagram for two lamps from one choke

The scheme provides for the presence of two starters and one choke. The most expensive element of the circuit is the inductor. A more economical option is a two-lamp lamp with a choke. The video explains how to implement the scheme.

The disadvantages of the electronic ballast circuit necessitated the search for a more optimal connection method. During the research, a method involving electronic ballast was invented. In this case, it is not the mains frequency (50 Hz) that is used, but high frequencies (20 – 60 kHz). It is possible to get rid of the flashing light that is harmful to the eyes.

Externally, the electronic ballast is a block with terminals exposed to the outside. The inside of the device contains a printed circuit board on which the entire circuit can be assembled. The unit is small in size, thanks to which it fits into the housing of even a small lighting device. Switching on is much faster compared to the EMPA standard. The operation of the device does not cause acoustic discomfort. This connection method is called starterless.

It is not difficult to understand the principle of operation of a device of this type, since there is a diagram on its reverse side. It shows the number of lamps for connection and explanatory notes. There is information about the power of the light bulbs and other technical parameters of the device.

The connection is made as follows:

The first and second contacts are connected to a pair of lamp contacts.
The third and fourth contacts are directed to the remaining pair.
Power is supplied to the input.

Using Voltage Multipliers

This option allows you to connect a fluorescent lamp without using an electromagnetic balance. Usually used to increase the service life of light bulbs. The connection diagram for burnt-out lamps makes it possible for the light sources to work for some more time, provided that their power is no more than 20 - 40 W. Filaments are allowed both suitable for work and burnt out. In any case, the thread leads must be short-circuited.

As a result of rectification, the voltage doubles, so the light bulb turns on almost instantly. Capacitors C1 and C2 are selected based on an operating voltage of 600 Volts. The disadvantage of capacitors is their large size. As capacitors C3 and C4, preference is given to mica devices rated at 1000 Volts.

Fluorescent lamps are not compatible with direct current. Very soon, so much mercury accumulates in the device that the light becomes noticeably weaker. To restore the brightness of the glow, change the polarity by turning the bulb over. Alternatively, you can install a switch so you don't have to remove the lamp every time.

Connection without starter

The method using a starter involves prolonged heating of the light bulb. In addition, this part must be changed frequently. A scheme where the electrodes are heated using old transformer windings allows you to do without a starter. The transformer acts as ballast.

Bulbs used without a starter must be marked RS (quick start). A light source started through a starter is not suitable, since its conductors take a long time to heat up and the spirals burn out quickly.

Serial connection of two light bulbs

In this case, it is necessary to connect two fluorescent lamps with one ballast. All devices are connected in series.

To carry out electrical work you will need the following parts:

induction throttle;
starters (2 units);
fluorescent light bulbs.

The connection is made in the following order:

We connect starters to each light bulb. The connection is made in parallel. The connection point is the pin input at the ends of the lighting device.
We direct free contacts to the electrical network. We use a choke for connection.
We connect capacitors to the contacts of the light source. They will allow you to reduce the intensity of interference in the network and compensate for power reactivity.

Note! In standard household switches (especially in inexpensive models), contacts often stick due to too high starting currents. In this regard, it is recommended to purchase high-quality switches for use in conjunction with fluorescent lamps.

Replacing the lamp

If there is no light and the cause of the problem is only to replace a burnt out light bulb, proceed as follows:

Let's disassemble the lamp. We do this carefully so as not to damage the device. Rotate the tube along its axis. The direction of movement is indicated on the holders in the form of arrows.
When the tube is rotated 90 degrees, lower it down. The contacts should come out through the holes in the holders.
The contacts of the new light bulb must be in a vertical plane and fit into the hole. When the lamp is installed, turn the tube in the opposite direction. All that remains is to turn on the power supply and check the system for functionality.
The final step is the installation of a diffuser lamp.

System health check

After connecting the fluorescent lamp, you should make sure that it is working and that the ballasts are in good working order. To carry out the tests, you will need a tester with which to check the cathode filaments. The permissible resistance level is 10 ohms.

If the tester determines the resistance to be infinite, it is not necessary to throw away the light bulb. This light source still retains functionality, but it must be used in cold start mode. In the normal state, the starter contacts are open, and its capacitor does not allow direct current to pass through. In other words, the ringing should show a very high resistance, which sometimes reaches hundreds of ohms.

After touching the choke terminals with the ohmmeter probes, the resistance gradually decreases to a constant value inherent in the winding (several tens of Ohms).

Note! The faulty state of the throttle is indicated by the burnout of a recently installed light bulb.

It is not possible to reliably determine the turn-to-turn short circuit in the inductor winding using a conventional ohmmeter. However, if the device has an inductance measurement function and data on electronic ballasts, a discrepancy between the values will indicate a problem.