Electronic ballast: device, repair and connection diagram for fluorescent lamps

Make it yourself

Tubular luminaires with a length of 1200 mm are inexpensive and can illuminate large areas. The lamp can be made with your own hands, for example, from 2 lamps of 36 W each.

1. The body is a rectangular base made of non-combustible material. You can use a used lamp that no longer requires repair.
2. Electronic ballasts are selected according to the power of the lamps.
3. For each lamp you will need 2 G13 sockets, stranded wire and fasteners.
4. Lamp sockets are attached to the body after selecting the distance between them.
5. Electronic ballasts are installed in the zone of minimal heating from the lamps (usually closer to the center) and connected to the sockets. Each unit is produced with a connection diagram on the case.
6. The lamp is mounted on the wall or ceiling with a connection to a 220 V power supply via a switch.
7. It is advisable to use a transparent cap to protect the lamps.

Repair instructions

Now we will look at the main faults that can be fixed without much investment. Let's start with the electronic ballast, because in its circuit there are quite a lot of elements that can fail, and besides, tubular fluorescent lamps with electronic ballasts are more common today.

Ballast

The most common fault is transistor breakdown. This failure can only be determined by removing the transistors from the circuit and checking them with a tester. In the whole transistor, the transition resistance is ~ 400-700 Ohms. As the transistor burns, it pulls a resistor in the base circuit with a nominal value of 30 ohms.

There is also a fuse or a low-resistance 2-5 Ohm resistor on the board; most likely it will have to be replaced, at which point the repair will end. You may additionally have to change the diode bridge or its elements.

You may decide that it will be cheaper to purchase a new electronic ballast than to repair a broken one. Replacing the starting equipment should not be difficult, because the connection diagram is printed on the device itself. Upon careful study, it is easy to understand, L and N are terminals for connecting to a 220V network.

We also recommend watching a video that clearly shows how to repair the electronic ballast of a fluorescent lamp yourself:

Please note that this technology can also be used to repair an energy-saving CFL light bulb. For example, if one filament has burned out, repair is the following procedure: Housekeeper repair

Expert opinion

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Circuits of electronic ballasts for fluorescent lamps

Electronic ballasts are an electronic board filled with electronic components. The circuit diagram of the connection (Fig. 1) and one of the options for the ballast circuit (Fig. 2) are shown in the figures.

Fluorescent lamp, C1 and C2 – capacitors

Electrical diagram of electronic ballasts

Electronic ballasts can have different circuit designs depending on the components used. The voltage is rectified by diodes VD4–VD7 and then filtered by capacitor C1. After voltage is applied, capacitor C4 begins charging. At a level of 30 V, dinistor CD1 breaks through and transistor T2 opens, then the self-oscillator on transistors T1, T2 and transformer TR1 is switched on. The resonant frequency of the series circuit of capacitors C2, C3, inductor L1 and generator are close in value (45–50 kHz). The resonance mode is necessary for stable operation of the circuit. When the voltage on capacitor C3 reaches the starting value, the lamp lights up. At the same time, the regulating frequency of the generator and voltage are reduced, and the inductor limits the current.

Photo of the internal structure of the electronic ballast

Photo of a typical electronic ballast device

Operating principle of the starter

Whatever circuit is used to start a fluorescent lamp. The general operating principle remains unchanged. In principle, similar processes occur when using a throttle and starter. There are only three phases:

• Initial heating of the electrodes. In electronic ballasts this occurs by a fairly gentle increase in voltage on the tungsten filaments.
• Arson. At this moment, the circuit delivers a high-voltage pulse (usually about one and a half kilovolts). This is enough for electrical breakdown of gas and mercury vapor. The ignition voltage of fluorescent lamps is significantly higher than the combustion voltage.
• Combustion. After a high-voltage pulse, the circuit reduces the voltage to that required to maintain the glow discharge. The AC frequency at the electrodes can reach 38 kHz depending on the circuit.

In electronic ballasts, the igniting impulse is provided by an electronic circuit. In the classical scheme - due to the energy accumulated by the inductor. Warming up of the electrodes is also provided by electronic ballasts. With a starter switching circuit, the electrodes warm up at the moment the starter contacts close. It can be replaced with a push button.

How to check electronic ballast for fluorescent lamps?

If in a dark room, when the light source is turned on, a barely noticeable glow of the filaments is observed, then failure of the electronic ballast device is likely, as well as breakdown of the capacitor.

The standard circuit of all lighting devices is almost identical, but may have significant differences, so at the first stage of testing you need to decide on the type of electronic ballast.

Ballast check

The test begins with dismantling the tube, after which it is necessary to short-circuit the leads with the filaments and connect a traditional 220V lamp with low power ratings. Diagnostics of the device in a professional repair shop is carried out using an oscilloscope, frequency generator and other necessary measuring instruments.

Self-checking involves not only a visual inspection of the electronic board, but also a consistent search and identification of failed parts.

Budget ballast devices are characterized by the presence of quickly failing capacitors at 400V and 250V.

How the device works

You can understand the principle of operation of a fluorescent lamp using the example of the schematic image presented below.

On it you can see:

1. ballast (stabilizer);
2. a lamp tube including electrodes, gas and phosphor;
3. phosphor layer;
4. starter contacts;
5. starter electrodes;
6. starter housing cylinder;
7. bimetal plate;
8. filling the flask with inert gas;
9. filaments;
10. ultraviolet radiation;
11. breakdown.

A layer of phosphor is applied to the inner wall of the lamp in order to convert ultraviolet light, which is invisible to humans, into illumination received by normal vision. By changing the composition of this layer, you can change the shade of the color of the lighting fixture.

So, knowing the structure of the lamp and the circuit diagram of the lamp, you can begin to restore it.

General operating principle of the element

Essentially, the ballast for fluorescent lamps is a choke. It regulates the amount of current supplied by limiting or separating different frequency electrical signals. Eliminates DC ripple. The cathodes of fluorescent lamps are heated.

Next, they are supplied with the required amount of voltage, which activates the operation of the lighting device. The voltage is adjusted using a special regulator, which is soldered into the inverter circuit. It is he who adjusts the voltage range. Due to the above-mentioned features of the ballast, flickering in the light source is completely eliminated.

A starter is also built into the circuit. Its functions are voltage transmission and ignition. When the lamp is turned on, the current on the ballast chip decreases. This feature allows you to set the required operating mode of the lighting device.

Today, the following types of ballast devices are widely represented on the market:

• electromagnetic;
• electronic;
• ballasts for compact lamps.

The presented categories are marked by reliable operation and ensure long-term operation and ease of operation of all fluorescent lamps. All of these devices have identical operating principles, but differ in some respects.

Electromagnetic

These ballasts are suitable for lamps connected to the mains using a starter. The initially occurring discharge intensively heats up and short-circuits the bimetallic electrode elements. There is a sharp increase in operating current.

Electromagnetic ballast is easy to recognize by its appearance. The design is more massive compared to the electronic prototype.

When the starter fails, a false start occurs in the electromagnetic ballast circuit. When power is supplied, the lamp begins to blink, subsequently there is a smooth supply of electricity. This feature significantly reduces the working life of the lighting source.

Electronic

Today, magnetic and electronic ballasts are used, which consist in the first case of a microcircuit, transistors, dinistors and diodes, and in the second case of metal plates and copper wire. By means of a starter, the lamps are started, and the phenomenon is organized in the electronic version of the part as a single function of this element with the ballast in one circuit.

• light weight and compactness;
• smooth fast start;
• unlike electromagnetic structures that require a 50 Hz network to operate, high-frequency magnetic analogues operate without noise from vibration and flicker;
• heating losses are reduced;
• power factors in electronic circuits reach 0.95;
• Extended service life and safety of use are ensured by several types of protection.

For compact fluorescent lamps

Compact types of fluorescent lamps are represented by devices similar to incandescent lamps of types E27, E40 and E14. In such schemes, electronic ballasts are built inside the cartridge. In this design, repairs in case of breakdown are excluded. It will be cheaper and more practical to purchase a new lamp.

Interaction of fluorescent lamp components

In order for a fluorescent lamp to work, simply connecting it to a 220-volt electrical network, as is done with conventional incandescent light bulbs, is not at all enough. Starting is carried out using special ballasts, which can be electromagnetic (EMG) or electronic (EPG). Anyone who is planning to repair a fluorescent lamp on their own should know this feature.

Electromagnetic devices, although outdated, are still used in many lamps. They are characterized by low efficiency, noise and flickering during operation due to the low ripple coefficient. Their use to this day is due to their low cost, reliability and ease of repair.

The operation of the electronic ballast is carried out according to a certain scheme. To start a light bulb, you need to break through its internal gas environment. For this purpose, with the help of an energy storage device - a choke, a high voltage pulse is created. However, this circuit is not enough for the lamp to work and start burning. It is necessary to preheat the electrodes for subsequent emission and create a glow discharge.

This problem is solved using a starter connected in parallel with the lamp. This device is made in the form of a small glass bulb, inside of which there are contacts in the form of bimetallic plates. When voltage is applied, they are in a cold closed state and current begins to flow through them to the spirals. When current is applied, the bimetallic contacts heat up and open. The energy accumulated in the inductor maintains the flow of current until the breakdown of the gaseous medium occurs. After this, the fluorescent lamp begins to burn independently without outside help.

Electromagnetic devices are most often the cause of malfunctions. Electronic equipment provides better performance and does not break down as often. As a rule, such a unit fails entirely and must be completely replaced. Repair of the electronic ballast of a fluorescent lamp is carried out according to its own scheme, by sequential testing of all components.

Schematic diagram

This is a large part of this electronic ballast; the Chinese did not include the inductor and capacitor here.

Actually, a diagram faithfully copied from a printed circuit board. The rating of the electronic components that made it possible to do this was determined not only “by appearance,” but also using measurements, with preliminary desoldering of the components from the board. In the diagram, the resistor values ​​are indicated in accordance with the color coding. Only with regard to the choke, I allowed myself not to unwind the existing one to determine the number of turns, but measured the resistance of the wound wire (1.5 Ohms with a diameter of 0.4 mm) - it worked.

First assembly on the circuit board. I carefully selected the component values, regardless of size and quantity, and was rewarded - the light bulb lit up the first time. Ferrite ring (10 x 6 x 4.5 mm) from an energy-saving light bulb, its magnetic permeability is unknown, the diameter of the wire of the coils wound on it is 0.3 mm (without insulation). The first start-up is mandatory through a 25 W incandescent light bulb. If it is on and the fluorescent one initially blinks and goes out, increase (gradually) the value of C4, when everything worked and nothing suspicious was found, and removed the incandescent lamp, then reduced its value to the original value.

To some extent, focusing on the printed circuit board of the original source, I drew a signet for the existing suitable case and electronic components.

I etched the scarf and assembled the diagram. I was already looking forward to the moment when I would be satisfied with myself and glad to be. But the circuit assembled on a printed circuit board refused to work. I had to delve into and select resistors and capacitors. At the time of installation of the electronic ballast at the site of operation, C4 had a capacity of 3n5, C5 - 7n5, R4 resistance of 6 Ohms, R5 - 8 Ohms, R7 - 13 Ohms.

The lamp “fit” not only into the design; the lamp, raised all the way up, made it possible to comfortably use the shelf inside the secretary niche. Babay made the “room” feel comfortable.

A fluorescent lamp (LL) is a glass tube filled with an inert gas (Ar, Ne, Kr) with the addition of a small amount of mercury. At the ends of the tube there are metal electrodes for applying voltage, the electric field of which leads to gas breakdown, the occurrence of a glow discharge and the appearance of electric current in the circuit. The glow of the gas discharge is pale blue and very weak in the visible light range.

But as a result of an electrical discharge, most of the energy passes into the invisible, ultraviolet range, the quanta of which, entering phosphorus-containing compounds (phosphor coatings), cause a glow in the visible region of the spectrum. By changing the chemical composition of the phosphor, different glow colors are obtained: for fluorescent lamps (FLLs) various shades of white have been developed, and for decorative lighting you can choose lamps of a different color. The invention and mass production of fluorescent lamps is a step forward compared to low-efficiency incandescent lamps.

Connection diagram, startup

The ballast is connected on one side to the power source, on the other to the lighting element. It is necessary to provide for the possibility of installing and fastening electronic ballasts. The connection is made in accordance with the polarity of the wires. If you plan to install two lamps via ballasts, a parallel connection option is used.

The diagram will look like this:

A group of gas-discharge fluorescent lamps cannot operate normally without a ballast. Its electronic design ensures a soft, but at the same time almost instantaneous start-up of the light source, which further extends its service life.

Ignition and maintenance of the lamp's functioning is carried out in three stages: heating of the electrodes, the appearance of radiation as a result of a high-voltage pulse, maintenance of combustion is carried out by constantly applying a small voltage.

Failure detection and repair work

If there are problems with the operation of gas-discharge lamps (flickering, lack of glow), you can make repairs yourself. But first you need to understand whether the problem is in the ballast or the lighting element. To check the functionality of the electronic ballasts, the linear light bulb is removed from the luminaires, the electrodes are short-circuited, and a regular incandescent lamp is connected. If it lights up, the problem is not with the ballast.

Otherwise, you need to look for the cause of the failure inside the ballast. To determine the malfunction of fluorescent lamps, it is necessary to “ring” all the elements in turn. You should start with the fuse. If one of the circuit components fails, it must be replaced with an analogue. The parameters can be seen on the burnt element. Repairing ballasts for gas-discharge lamps requires the use of soldering iron skills.

If everything is in order with the fuse, then you should check for serviceability of the capacitor and diodes that are installed in close proximity to it. The capacitor voltage should not fall below a certain threshold (this value varies for different elements). If all the ballast elements are in working order, without visible damage, and the ringing also did not give anything, all that remains is to check the inductor winding.

In some cases it is easier to buy a new lamp. This is advisable to do in the case where the cost of individual elements is higher than the expected limit or in the absence of sufficient skills in the soldering process.

Repair of compact fluorescent lamps is carried out according to a similar principle: first, the housing is disassembled; The filaments are checked and the cause of the breakdown on the control gear board is determined. There are often situations when the ballast is fully operational, but the filaments are burned out. Repairing the lamp in this case is difficult. If there is another broken light source of a similar model in the house, but with an intact filament, you can combine the two products into one.

Thus, electronic ballasts represent a group of improved devices that ensure efficient operation of fluorescent lamps. If the light source is flickering or does not turn on at all, checking the ballast and its subsequent repair will extend the life of the light bulb.

Operating principle

Operating principle of fluorescent lamps

Let us briefly describe the interaction diagram between the starter, ballast and lamp:

1. When power is applied, the current, passing through the ballast, passes through the starter contacts along the tungsten spirals, heating them and then goes towards zero
2. The starter is equipped with a pair of contacts: movable and fixed. When current flows, the movable contact (bimetallic), heating up, changes its shape and connects with the first
3. In this case, the current immediately increases significantly to the limit limited by the inductor. The electrodes are heating up
4. The starter plate, on the contrary, begins to cool and disconnects the contacts. At this moment, a sharp surge in voltage occurs and electrons break through the gas. When mercury turns into vapor, the light source switches to operating mode
5. The starter is no longer involved in the process - its contacts are open.

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Connecting and repairing a ballast for fluorescent lamps

Ballast for a gas-discharge lamp (fluorescent light sources) is used to ensure normal operating conditions.
Another name is ballast (ballast). There are two options: electromagnetic and electronic. The first of them has a number of disadvantages, for example, noise, the flickering effect of a fluorescent lamp. Apartment renovation in Moscow https://remmstroy.ru/ We work under a contract without prepayment, all repairs are divided into stages, which you pay for when ready after signing the acceptance certificates. +7(495)1907098

The second type of ballast eliminates many of the disadvantages in the operation of the light source of this group, and therefore is more popular. But breakdowns in such devices also happen. Before discarding, it is recommended to check the ballast circuit elements for faults. It is quite possible to carry out electronic ballast repairs yourself.

Typical ballast circuit

The electronic ballast design uses an active power factor correction, ensuring compatibility with the electrical network. The basis of the corrector is a powerful boost pulse converter controlled by a special integrated circuit. This provides rated operation with a power factor close to 0.98. The high value of this coefficient is maintained in any operating mode. Voltage changes are allowed in the range of 220 volts + 15%. The corrector ensures stable illumination even with significant changes in network voltage. To stabilize it, an intermediate DC circuit is used.

An important role is played by the mains filter, which smoothes out high-frequency ripples of the supply current. Together with the corrector, this device strictly regulates all components of the consumed current. The line filter input is equipped with a protective unit with a varistor and a fuse. This allows you to effectively eliminate network overvoltages. A thermistor having a negative temperature coefficient of resistance is connected in series with the fuse, which ensures that the input current surge is limited when the electronic ballast is connected from the inverter to the network.

In addition to the main elements, the ballast circuit for fluorescent lamps requires the presence of a special protection unit. With its help, the status of the lamps is monitored, as well as their shutdown in case of malfunction or absence. This device monitors the current consumed by the inverter and the voltage supplied to each lamp. If during a certain period of time the specified voltage or current level exceeds the set value, then the protection is triggered. The same thing happens during a load circuit break.

The executive element of the protective unit is a thyristor. Its open state is maintained by current passing through a resistor installed in the ballast. The value of the ballast resistance allows the thyristor current to maintain the on state until the supply voltage is removed from the electronic ballast.

The electronic ballast control unit is powered through a mains rectifier when current passes through the ballast resistor. Reducing the power of the electronic ballast and improving its efficiency allows the use of smoothing circuit current. This circuit connects to the point where the inverter transistors connect. Thus, the control system is powered. The construction of the circuit ensures that the control system is launched at the initial stage, after which the power circuit is started with a slight delay.

Types and principle of operation

The main function of electronic ballasts is to convert alternating current into direct current. In another way, electronic ballast for gas-discharge lamps is also called a high-frequency inverter. One of the advantages of such devices is their compactness and, accordingly, low weight, which further simplifies the operation of fluorescent light sources. And the electronic ballast does not create noise during operation.

An electronic ballast, after connecting to a power source, provides current rectification and heating of the electrodes. In order for the fluorescent lamp to light up, a certain voltage is applied. The current is adjusted automatically, which is implemented using a special regulator.

This feature eliminates the possibility of flickering. The last stage is when a high-voltage pulse occurs. The fluorescent lamp is ignited in 1.7 s. If there is a failure when starting up the light source, the filament body immediately fails (burns out). Then you can try to make the repair yourself, which requires opening the case. The electronic ballast circuit looks like this:

The main elements of the electronic ballast of a fluorescent lamp: filters; the rectifier itself; converter; throttle. The circuit also provides protection against power supply surges, which eliminates the need for repairs for this reason. And, in addition, the ballast for gas-discharge lamps implements the power factor correction function.

According to their intended purpose, the following types of electronic ballasts are found:

• for linear lamps;
• ballast built into the design of compact fluorescent light sources.

What's happened

Electronic ballast uses solid-state electronic circuitry to provide proper starting and operating electrical conditions to power HID light bulbs. They are often based on an SMPS topology, first rectifying the input power and then chopping it at a high frequency. Advanced EBs may allow brightness to be adjusted using pulse width modulation or by changing the frequency to a higher value. Ballasts incorporating a microcontroller or digital circuits can offer remote control and monitoring over networks or simple analog control using a 0-10 VDC dimming signal.

The use of electronic ballasts for HID lighting is becoming increasingly popular. Most new generation EBs can operate with both high pressure sodium (HPS) lamps and metal halide devices, reducing the costs of lighting systems that use both types of lamps. Initially the ballast acts as an arc starter by providing a high voltage pulse and then it functions as a limiter/regulator of the electrical flow within the circuit. EBs operate much cooler and easier than their magnetic counterparts.

Principle of operation

A fluorescent light bulb is a gas-discharge light source in which a discharge of electricity in mercury vapor produces ultraviolet radiation. Due to exposure to ultraviolet light, a glow appears using a phosphor.

The operating principle of the lamp is shown in the diagram below:

Digital symbols on the diagram:

• stabilizer (ballast control device);
• lamp tube (includes electrodes, gaseous medium and phosphor);
• phosphor layer;
• starter contacts;
• electrodes;
• starter cylinder;
• bimetallic plate;
• flask filler (inert gas);
• filaments;
• ultraviolet radiation;
• breakdown.

Note! The phosphor layer is necessary to convert ultraviolet light. If you change the composition of the layer, you can get the desired shade of light.

Main varieties

Today there are two types of ballast - electromagnetic and electronic. They differ in how they work, so it’s worth getting to know each of them.

Electromagnetic ballast

This type of implementation involves connecting the inductor in series to the lamp. Also, for the operation of electromagnetic ballasts, a starter is required, with the help of which the ignition process of the lamp is regulated. This part is a gas-discharge lamp, inside the bulb of which there are bimetallic electrodes.

The device works as follows:

1. When voltage is applied to the starter, the bimetallic electrodes close due to heat. This leads to an increase in current strength, since it can only be limited by the internal resistance of the inductor windings.
2. As the electric current increases, the electrodes of the fluorescent lamp begin to heat up.
3. When the starter cools down, the bimetallic electrodes open.
4. When the circuit is broken by the starter, a high voltage pulse occurs in the throttle coil, which leads to the ignition of the lighting device.

When the luminescent device returns to normal operation, the voltage on it and the starter is 50% less than the mains voltage, and this is not enough to trigger the second element. As a result, the starter goes into a disabled state and ceases to influence the operation of the lighting device.

Electromagnetic ballast is characterized by low cost and simple design. For a long time, these devices were actively used in the manufacture of lamps, but they have a number of disadvantages:

1. It takes about 3 seconds for the luminescent device to enter operating mode.
2. Lighting devices with electromagnetic ballast flicker during operation, which negatively affects the organs of vision.
3. The energy consumption of these devices is significantly higher compared to electronic ballast.
4. The throttle is noisy during operation.

Electronic implementation

Electronic devices are voltage converters that provide power to fluorescent lamps. Although many variations of electronic ballast have been created, most use a single block diagram. At the same time, manufacturers can make certain changes to it, for example, adding a brightness control circuit for a lighting fixture.

Transferring a fluorescent lamp lamp to normal operation using electronic ballasts is most often carried out in one of two ways:

1. Before the ignition voltage is applied to the cathodes of the lamp, they are preheated. This allows you to get rid of flicker and also increase the efficiency of the lighting device.
2. An oscillatory circuit is installed in the design of the lamp, which enters into resonance before a discharge appears in the lamp bulb.

Scheme of ballast for 36w lamps.

Fluorescent lamp malfunctions and ways to eliminate them

The first step is to check if there is a fault in the fluorescent lamp using a tester or multimeter. It must be remembered that in the circuit, for example, of an Armstrong lamp with electronic ballasts for 4 lamps (4 x 18), if one burns out, all four will not work. In devices with one starter for 2 tubes, both tubes must be working, but when connected with a starter, one working lamp is enough for each lamp, and the lamp will work even if the second one is faulty.

After applying power, if the lamp does not light, you need to check the voltage supply to it. This can be done from the input terminal block.

Electronic circuits

Depending on the type of a particular light bulb, electronic ballast elements may have different implementations, both in electronic filling and in built-in features. Below we will consider several options for devices with different power and design.

Electronic ballast circuit for fluorescent lamps with a power of 36 W

Depending on the electronic parts used, the type and technical characteristics of the ballasts may differ significantly in the electrical circuit, but the functions they perform will be the same.

In the above figure, the circuit uses the following elements:

• diodes VD4–VD7 are designed for current rectification;
• capacitor C1 is designed to filter the current passing through the diode system 4-7;
• capacitor C4 begins charging after voltage is applied;
• dinistor CD1 breaks through when the voltage reaches 30 V;
• transistor T2 opens after breaking through 1 dinistor;
• transformer TR1 and transistors T1, T2 are started as a result of activation of the autogenerator on them;
• the generator, inductor L1 and series capacitors C2, C3 begin to resonate at a frequency of approximately 45–50 kHz;
• capacitor C3 turns on the lamp after it reaches the starting charge value.

Electronic ballast circuit based on a diode bridge for LDS with a power of 36 W

The above circuit has one feature - the oscillatory circuit is built into the design of the lighting device itself, which ensures resonance of the device until a discharge appears in the bulb.

Thus, the filament of the lamp will act as part of the circuit, which at the moment of the appearance of a discharge in a gaseous medium is accompanied by a change in the corresponding parameters in the oscillatory circuit. This takes it out of resonance, which is accompanied by a decrease in voltage to the operating level.

Electronic ballast circuit for LDS with a power of 18 W

Lamps that are equipped with E27 and E14 bases are most widespread among consumers today. In this device, the ballast is built directly into the structure of the device. The corresponding diagram is shown above.

Electronic ballast circuit based on a diode bridge for LDS with a power of 18 W

It is necessary to take into account the peculiarity of the structure of the self-oscillator, which is based on a pair of transistors.

Power is supplied from the step-up winding, indicated in diagram 1-1 of transformer Tr. Parts of the series oscillatory circuit are inductor L1 and capacitor C2, the resonant frequency of which is significantly different from that generated by the self-oscillator. The above diagram is used for budget class table lighting fixtures.

Electronic ballast circuit in more expensive devices for LDS with a power of 21 W

It should be noted that simpler ballast circuits, which are used for LDS-type lighting devices, cannot guarantee long-term operation of the lamp, since they are subject to heavy loads.

For expensive products, such a circuit ensures stable operation throughout the entire service life, since all elements used meet more stringent technical requirements.

How to fix a lamp with fluorescent lamps?

It is a well-known fact that lamps with fluorescent lamps are widespread not only in factories and organizations, but also in private houses and apartments. Surely every second person has an old, dusty similar lighting device in their garage or closet that no longer works, and it would be a pity to throw it away. Then why not repair these lamps yourself? Moreover, if it is possible to find old and unnecessary lamps somewhere, repairs will not cost a penny, and now we’ll figure out how to repair them.

The main thing you need to know before you start repairing fluorescent lamps is the principle of their operation.

Connection diagrams for fluorescent lamps using EMF

EMPRA is an electromagnetic ballast, and in fact, an ordinary choke. In the circuit diagram for connecting the EMGR, a starter is required, which creates the first impulse to start the fluorescent lamp to glow.

Read, electronic ballasts and emballasts. What are the differences between ballasts

Connection diagram for a fluorescent lamp EMPRA

This connection diagram is used in most standard single-lamp local lighting luminaires of economy class.

Circuit inductive implementation

• Supply voltage 220 Volts;
• The inductor (LL) is connected in series to the power wire and lamp terminal 1;
• The starter is connected in parallel to terminals 2 and 3 of the lamp;
• Pin 4 of the lamp is connected to the second power wire;
• The circuit involves a capacitor, which reduces the voltage pulse, increases the service life of the starter and reduces radio interference when the lamp is operating.

Circuit inductive-capacitive implementation

The second connection circuit is called inductive-capacitive. In it, the inductor and capacitor (inductive and capacitive reactance of the circuit) are connected in series. The starter is still connected in parallel with the output of lamp 2-3.

Connection diagram for 2 fluorescent lamps up to 18 W (EMP)

The connection diagrams change slightly with two lamps. The most common two circuits are for lamps up to 18 W (series) and lamps 36 W (parallel).

In the first scheme, two starters are still involved, one starter for each lamp. The inductor is connected as in an inductive circuit. The power of the choke is selected by summing the power of the lamps.

Important! In this (series) circuit, it is necessary to use 127 (110-130) Volt starters. Lamp power cannot be more than 22 W

In the second parallel circuit, two chokes (LL1 and LL2) are already involved. There are still two starters, one starter for each lamp.

Important! This circuit uses 220-240 Volt starters. Lamp power up to 80 W

Important note. Modern electronic ballasts are produced in a single housing

For connection, there are only contact pins on the case. The lamp connection diagram is indicated on the housing.

Electronic ballast device

An electronic ballast is a complex electronic device. Includes:

• Interference filter: necessary to level out the influence of interference from and into the electrical network;
• Rectifier: needed to convert AC to DC;
• Optional: power corrector;
• Anti-aliasing filter: used to reduce ripple;
• Inverter: increases the voltage to the required level;
• Ballast: analogue of an electromagnetic choke.

In some models, the inverter can be supplemented with a brightness control. To do this, you need an external dimmer (either manual or automatic based on a photoresistor). A lot of schemes have been developed. The element base of electronic ballasts for daytime fluorescent lamps is very diverse: from powerful field-effect transistors in a bridge circuit with loads of hundreds of watts, to driver microcircuits in low-power lamps. But nevertheless, the operating algorithm is the same.

In a simplified form for one fluorescent lamp, the diagram looks like this:

Those. the circuit consists of only two components: a fluorescent lamp and an electronic starter. From an electrician's point of view, this is much simpler than the classic lamp circuit using an electromagnetic choke and starter. Terminals N and L are supplied with mains voltage. Ground pin – grounding. For electronic ballasts to operate, connecting a grounding contact is not mandatory and serves only for safe operation.

The connection diagram for two lamps is similar.

There are no additional elements in it; the circuit is supplemented only by a second lamp, the terminals of which are connected directly to the electronic unit.

Electronic ballast circuits are complex and consist of many electronic components. It is very difficult for a person without an engineering education to understand the diagram. In addition, not every electrician will be able to understand the internal structure.

One of the options for the electronic ballast circuit diagram

This is a fairly simple circuit for an electronics engineer. In a simplified sense, the scheme works as follows. Rectification is carried out by a full-wave rectifier - a diode bridge. Ripple smoothing is performed by an electrolytic capacitor designed for a voltage higher than the mains voltage, since the amplitude value of the sinusoid for the alternating current mains is approximately one and a half times higher than the mains voltage (√2*220V). The remaining processes are controlled by the microcircuit. Field-effect transistors are responsible for supplying voltage to the lamps. Then the converter operates autonomously, the frequency does not change.

Knowledge of electronics allows you to create a power supply circuit for a fluorescent lamp from low-voltage sources. The scheme turns out to be quite compact. The most important thing is to wind the transformer correctly.

Schematic diagram of powering a fluorescent lamp from a low-voltage source

Operating principle of electronic ballast

The action of electronic ballasts is directly related to the operating principle of the fluorescent lamp itself. The main stage is its launch, during which certain conditions must be met. First of all, both filaments are heated, after which they are supplied with high voltage, about 600 volts. The value of the ignition voltage is directly dependent on the length of the glass tube. The shorter the lamp and the lower its wattage, the lower the required starting voltage will be.

At the initial stage, the input mains voltage is rectified to a constant value within 260-270 V and its subsequent smoothing using an electrolytic capacitor C1. This is clearly visible in the diagram presented.

Then the work of a push-pull half-bridge converter begins, consisting of two high-voltage bipolar transistors with a p-p-p structure. These transistors perform the function of switches, and the entire circuit converts a direct voltage of 260-270 V into a voltage with a high frequency of up to 38 kHz. Due to this, the size and weight of the device are reduced.

The electronic ballast circuit includes a transformer that simultaneously performs load and control functions. Of its three windings, two four-turn windings are control windings, and one two-turn winding is working. The working winding included in the circuit creates the necessary load for the converter.

Initially, the converter is started using a symmetrical dinistor, which opens if the voltage exceeds the operating threshold at the connection points. When in the open state, it sends a pulse to the transistor base, which causes the converter to start. A capacitor located in the resonant circuit and connected directly to the lamp provides a voltage drop to the level at which the lamp lights up.

Thus, with the help of the maximum current, both filaments are heated, and the lamp is directly ignited due to the high resonant voltage on the capacitor. When the lamp is lit, the resistance decreases, but the remaining voltage resonance ensures its continued combustion. Current limitation occurs due to the inductance of the inductor. Despite such a detailed description, it actually takes less than 1 second to light a fluorescent lamp.

Causes of problems with fluorescent lamps

The main problems in the operation of fluorescent lamps are related to the condition of the ballast, called ballast. In electromagnetic devices, the starter and choke most often fail, and in electronic devices, various semiconductor and other elements burn out. This feature should be taken into account when repairing lamps with fluorescent lamps.

In addition to malfunctions in the starting and control equipment, malfunctions may also occur in the lighting source itself. Most often this occurs as a result of wear, aging or burnout of individual parts and components. Therefore, knowing the device, you can easily determine the reason why the lamp does not start or light up.

One of the main signs of a malfunction is the device blinking during startup. This is how they differ from ordinary light bulbs, which burn out instantly. The blinking process indicates possible changes in the chemical composition of the gas environment during operation. In such cases, the content of mercury vapor decreases due to their gradual degeneration. Sometimes the cause of blinking is burnt-out electrodes, on which the amount of active substance applied decreases.

When the fluorescent lamps begin to blink, blackening at the ends of the glass tube becomes clearly visible. It is the appearance of soot that indicates a burnt-out coil and irreversible chemical processes. In such cases, repairs are no longer carried out, only extending the service life for a short time is possible. For this, a simple circuit or electronic device with a cold start function is used, connected to the contact terminals.

In some cases, blinking may occur when you turn on even a fully functional lamp. This happens under the influence of unfavorable factors. For example, the starter circuit may break when the sine wave passes the zero mark, and then the induction pulse is not enough to ionize the internal gas environment.

The same reason causes flashing at startup due to low mains voltage. Subsequently, during operation, in the absence of voltage surges, a working lamp operates smoothly and steadily, since the ballast maintains a certain level of current in the gas mixture.

Electronic ballast circuits 4×18 (2×36)

EB 4×18 is used with inverting capacitors with a capacity of 5 pF. Thus, the resistance of this module can increase to 40 Ohms. Another feature of this circuit is the location of the choke element (it can be found below the dinistor).

Electronic ballast circuit 4×18

The circuit above uses only one transistor. The transformer performs the function of reducing and rectifying the current. This element protects the device from overloads, but there is also a fuse in the circuit.

Scheme for "Navigator"

Another 4×18 EB is “Navigator”. The circuit also contains a step-down transformer and a transistor. The main difference is the presence of a special regulator that allows you to change the output voltage. The capacitive resistor also distinguishes this circuit from the previous one.

Note! Here two capacitors with a capacity of 5 and 7 pF are used. This allows you to create resistance up to 40 ohms

This circuit does not use a fuse.

Scheme 2x36

The 2x36 ballast circuit includes a transceiver for expansion. The device is connected using an adapter device. As in the previous versions, there are capacitors, but their capacitance is smaller, only 4 pF. The circuit is distinguished by the presence of thyristors and frequency regulators. For most models of modules of this type, you can see two rectifiers in the circuit. The operating voltage of such a ballast is 200 V, and the frequency is 55 Hz.

Electronic ballast 4x18 is a necessary device to maintain the integrity of fluorescent lamps. There are several schemes to connect it. You can choose the most suitable and easiest to implement.

Radio as a hobby

Repairing a fluorescent lamp

For several years I have been using a lamp with a tubular 18-watt fluorescent lamp. It (the lamp) did not cause any particular complaints... Apart from replacing burnt-out fluorescent lamps, there were no operational failures. But, as they say, nothing lasts forever...

Some time ago, when I tried to turn on the lamp, a bang was heard inside it, accompanied by a flash. The lamp was immediately de-energized, removed and pushed onto the far shelf in the pantry. Given its advanced age, the first decision was to throw the lamp in a landfill. Later, it was decided to try to repair it.

Let's start the renovation.

We disassemble the lamp and remove the fluorescent lamp. The first step is to check the lamp filament with an ohmmeter for breakage. The filaments turned out to be intact, and accordingly the lamp turned out to be in good working order and suitable for further use.

After opening the lamp, I was immediately struck by the terrible condition of the factory power cord, which was located inside the lamp body. The cord insulation cracked in many places, lost its elasticity and crumbled right under my fingers.

This is what the power cord looks like after ten years of use.

This state of the wire poses the following dangers:

-possibility of electric shock;

- the possibility of a short circuit and, as a result, fire;

Therefore, we change this cord first!

We continue to work... A popping sound inside the lamp clearly indicated a failure of the electronic ballast.

Removing the electronic ballast

A visual inspection did not reveal any burnt resistors. The mains fuse was also good. The mains fuse is the leftmost part on the ballast plate and is designated F1.

But the electrolytic capacitor with a nominal value of 4.7 µF x 400V turned out to be swollen

In order to carry out further repairs without blindness, I had to search the Internet for circuit diagrams of electronic ballasts. There are a great variety of them, and they are very similar to each other. The difference is only in the ratings of some parts, the presence/absence of additional protective elements and the type of transistors.

An attempt to compare the ballast diagram from my lamp with diagrams from the network showed that, in our case, additional elements were included in the ballast diagram. Therefore, in order not to rack my brains, I had to draw up a circuit diagram using a printed circuit board.

First of all, in such cases, we check the transistors. Both transistors turned out to be unusable with broken B-K junctions. This ballast uses transistors of the EB13003 type, which are analogues of the MJE13003 transistor, but have a different pinout from the original. This must be taken into account when replacing failed transistors.

Further inspection revealed that resistors R2, R3, R4, R5, R6, R7 had become unusable. The nature of the malfunction for all resistors is similar - an increase in resistance to 1 MΩ or more.

Failed elements are marked with red circles on the circuit diagram

All capacitors (except for the above electrolyte C2) turned out to be serviceable.

Instead of unusable ones, we solder in resistors of the MLT-0.125 type with the required values.

Instead of EB13003 transistors, we solder some Chinese type S13003.

We assemble the lamp in the reverse order.

Test activation... Everything worked. ))

The question of finding out the cause of failure of radio components is always interesting. In relation to this lamp, or more precisely, to its electronic ballast, my thoughts are as follows... After the repair, I noticed that the body of the lamp in the area where the electronic ballast is installed noticeably heats up. I didn’t pay any attention to this before. Heating indicates that the radioelements are operating under severe temperature conditions. In my opinion, this is one of the main reasons for the failure of radio elements. The first one that apparently failed due to overheating was the 4.7 µF x 400V electrolytic capacitor, which is a filter after the diode bridge. The deterioration of rectified voltage ripple suppression increased the level of voltages applied to the transistor junctions. Next, one of the transistors flew out, and then, according to the domino principle, another one flew out, along the way, the resistors in the base and emitter circuits burned out.. And that’s all.. Next was the repair.

How to choose the right one

Before choosing a device for lighting lamps, pay attention to the following characteristics:

Type, power and number of lamps in the lighting scheme. The specification sheet for an electronic fluorescent ballast will indicate what types and configurations of fixtures are designed to operate the ballast. Start type - instant or programmed. If the lighting system is subject to frequent switching due to occupancy sensors or other factors, select “programmed start.” Otherwise, "instant" is the best choice. Ballast factor. The usual ballast factor (0.77 to 1.1) is the default value for most general lighting. A low ballast factor (1.1) is useful when the goal is to increase light output for areas such as warehouses or large retail stores. In this case, the user will receive approximately a 10% increase in luminous flux compared to the nominal illumination of the device. Input voltage. Some EBs provide universal voltage, others specific voltage. In any case, check the input voltage requirements - 120/277/347 V. Minimum initial temperature. Ballast specification sheets include temperatures that will vary depending on the type of fixture being controlled by the ballast. For example, EB can show a minimum initial temperature from −17 C to +30 C. Obviously, the variations are quite significant. Therefore, when choosing an EB, they proceed from the minimum and maximum air temperatures in the room. The normal connection diagram is parallel. This allows other lights to remain lit even if one bulb in the fixture goes out. Anti-stratification control: Strata are unwanted bright and dim areas that can form a standing wave structure along the entire length of the fixture. Streaks are more likely to occur when the lamp is operated at low temperatures. Manufacturers have developed ways to minimize these areas and often refer to the anti-stripping feature in the EB specification. Sound rating. An EV with a rating of “A” will hum quietly, with a rating of “D” it will cause a pronounced noise

The importance of sound assessment depends on the purpose of the premises. In libraries, LLs with the quietest ballast are installed, while this parameter is not so important for warehouses. LED Transition: Some EV manufacturers have lists of instant and programmed starting ballasts that they call "LED Ready". Manufacturer's warranty.

Types of ballast

Different types of ballasts are grouped by implementation type: electronic and electromagnetic implementation. In addition, the models are classified according to the area of ​​application for lighting devices, among which are:

• High frequency electronic ballast for fluorescent luminaires, with or without preheating. The first model increases the performance and service life of the device, and also reduces the noise effect. Ballast without preheating consumes less energy. High frequency ballast for sodium lamps. This is a less bulky ballast than conventional models installed on low-pressure lamps, easy to install, and with low energy consumption for its own needs.
• Electronic ballast for gas discharge devices. This model is usually designed for high pressure sodium and metal lamps, increasing their lifespan by up to 20% compared to the standard. The start-up time is reduced, as are the flashing effects. It should be noted that these ballasts are not suitable for all luminaires.
• Multi-lamp ballast. It has the advantage that it can be used with several types of fluorescent devices, including aquarium lighting, creating an optimal primer. It has the function of recording all lighting parameters in its memory.
• Digitally controlled ballast. This is the latest generation model, offering a lot of flexibility and modularity when installing luminaires. This improves the economic aspect of the LED lamp and the brightness comfort. At the same time, it is the most expensive model.

Electromagnetic implementation

Magnetic ballasts (MB) are devices with old technology. They are used for the fluorescent lamp family and some metal halide devices. They tend to cause humming and flickering because they regulate current gradually. MBs use transformers to convert and control electrical power. When the current arcs through the light fixture, it ionizes a larger percentage of the gas molecules. The more of them are ionized, the lower the gas resistance. Thus, without MB, the current will rise so high that the lamp will heat up and destroy.

The transformer, which in MB is called a “choke”, is a wire coil - an inductor that creates a magnetic field. The more current flows, the greater the magnetic field, the more the current growth slows down. Because the process takes place in an alternating current environment, the current flows in one direction for only 1/60 or 1/50 of a second and then drops to zero before flowing in the opposite direction. Therefore, the transformer only needs to slow down the flow of current momentarily.

Electronic implementation

The performance of electronic ballasts is measured using various parameters. The most important is the ballast factor. This is the ratio of the luminous output of a lamp, controlled by the EB in question, to the luminous output of the same device, controlled by a reference ballast. This value ranges from 0.73 to 1.50 for EB. The significance of this wide range lies in the levels of light output that can be achieved using a single EB. This finds great use in dimming circuits. However, it has been found that too high and too low ballast factors degrade luminaire life due to lumen wear resulting from high and low current, respectively.

You might be interested in: Features of connecting IZU for DNAT

Electronic implementation

When EBs are to be compared within the same model and manufacturer, the ballast efficiency ratio is often used, which is the ratio of the ballast ratio expressed as a percentage to power and provides a relative measurement of the system efficiency of the entire combination. A measure of the efficiency of a ballast, power factor (PF) is a measure of the efficiency with which the EB converts supply voltage and current into usable power supplied to the lamp with an ideal value of 1.

What is electronic ballast

Electronic ballasts are electronic ballasts that can significantly extend the service life of lighting devices and make their operation more efficient. The component represents a module with contacts to which the input voltage terminals are connected, as well as a load in the form of lamps.

The electronic ballast unit has become an effective replacement for obsolete stabilizers using chokes and starters. It is the electronic module that is installed in all modern devices.

Causes of malfunctions

The main element of a fluorescent lamp is a ballast (ballast). There are electromagnetic (EMP) and electronic (EPG) ballasts. An electromagnetic ballast contains a choke and a starter, while an electronic device provides functionality through the operation of radio-electronic elements.

Most of the lamp failures are associated with the failure of some components of the electronic circuit, aging, wear and tear and burnout of the light bulb itself. Repair of fluorescent lamps begins with identifying the cause that led to the problem.

Lamp flashing

Standard incandescent lamps burn out instantly and completely unexpectedly. Fluorescent lamps wear out gradually. The light source begins to blink when turned on. This symptom indicates changes in the chemical composition of the gas that produces the glow (degeneration of mercury vapor) and indicates burnout of the electrodes.

A flashing fluorescent lamp usually has blackening on the end, which is carbon deposits. The phenomenon occurs as a result of a burnt-out spiral and neglected chemical processes in the inside of the flask. It is impossible to repair such a lamp to the condition of a new product, but it is quite possible to extend its service life.

Flashing of the lamp is also possible as a result of a malfunction of the electronic ballast or electronic ballast. In this case, the lamp will need to be replaced to determine the failure.

There is no need to throw away the light bulb itself. There are regulations according to which fluorescent light sources must be disposed of in compliance with certain rules, since there is mercury vapor inside the fluorescent lamp.

Another reason not to throw away a fluorescent lamp is that even with burnt-out filaments, the life of the device can be extended. Repair work consists of soldering some elements of the lamp or connecting it to electronic ballasts using the cold start method.

In some cases, even the working lamp begins to blink during switching on due to a number of negative events, such as the interruption of the starter circuit when the sine wave is at zero. In such a situation, the induction voltage surge is not enough to ionize the gaseous medium in the flask.

Flashing occurs at the start due to insufficient voltage in the electrical network. During operation, there should be no blinking, since the ballast keeps the current at a given level.

Design and principle of operation of electronic ballasts

Any electronic ballast consists of the following elements:

• device for current rectification;
• electromagnetic radiation filter;
• circuit power factor correction unit;
• voltage smoothing filter;
• inverter;
• choke or ballast for lamps.

The structure can be pavement or half-bridge. The first option has improved characteristics and is used in high-power lamps, from 100 W. The circuit effectively maintains the glow indicators and the voltage supplied to the cathodes.

Half-bridge circuits are more popular because Suitable for most household fluorescent lamps up to 50 W. Designs marked 2x36 support the connection of two 36 V lamps.

The operation of the device consists of the following steps:

1. Turning on and preheating the filaments. This is an important manipulation that significantly extends the life of lighting sources. Without preheating, the lamp will not turn on at low temperatures.
2. Generation of a high-voltage impedance pulse with a voltage of about 1.5 kV, which causes a breakdown of the gaseous medium inside the flask and starts the glow.
3. Stabilize voltage and maintain it at the required level. The voltage to support combustion is low, which makes the circuit safe.

Old style electromagnetic device

For a long time, electromagnetic units were used in circuits to regulate glow indicators. They were quite effective, but were characterized by increased sensitivity to voltage changes and bulky dimensions.

The old-style module included two components: a throttle and a starter. The choke was responsible for the load and voltage reduction, the starter generated the discharge.

The choke, acting as a ballast, took up a lot of space and did not allow the creation of compact light sources.

The scheme included one or two starters. The durability of the lamp depended on the quality and efficiency of the starters. Starter faults caused false starts and significant overcurrent.

One of the disadvantages of old-style ballasts can be considered the strobing effect in the form of flickering. Light pulsations negatively affect human vision and cause discomfort.

There were significant energy losses, reducing the efficiency of the lamp.

Improvement of the design to electronic ballasts

The improved ballast design for fluorescent lamps began to be widely integrated into electronic circuits about 30 years ago.

The new device was a complex of semiconductor devices, more compact than traditional circuits. At the same time, the quality of voltage stabilization has risen to a higher level.

Electromagnetic regulators have been replaced by more advanced semiconductor components, with which you can precisely adjust the glow parameters.

Energy-saving lamps: operating principle of the lighting circuit in pictures

The operating principle of CFLs is the same as I showed briefly above. The same processes occur here:

• heating the filaments to ensure electronic emission;
• breakdown of the gaseous medium by a pulse of increased voltage;
• prevention of arc fault.

Only all these functions are assigned to electronic ballasts - ballasts or an electronic starter built into a standard lamp base.

It is made of non-flammable plastic, and the electronic starter is made on a regular round printed circuit board.

There are also other designs when the electronic ballast mechanism is made of two separate blocks:

1. network rectifier with a high-frequency filter for suppressing outgoing interference;
2. h/h converter.

A similar scheme is common in switching power supplies for complex digital electrical devices.

I will provide a more detailed description of its components below.

Advantages and disadvantages of electronic ballasts

The use of electronic ballasts makes significant positive changes in the operation of fluorescent lighting devices. The main advantages of electronic ballasts are the following:

• The maximum light output is noticeably increased while simultaneously reducing the amount of electricity consumed by the power supply.
• A distinctive feature of old fluorescent lamps - flicker - is completely absent.
• There is practically no noise or buzzing during operation of the lamp.
• Increasing the service life of fluorescent lamps.
• Convenient settings and control of the brightness of the light flux.
• Lamps with electronic equipment are not at all affected by surges and surges in voltage in the supply network.

The main disadvantage of electronic ballasts is their high cost compared to electromagnetic devices. Currently, the latest technologies in this area are constantly being developed and improved. In this regard, the price of electronic products is gradually approaching the cost of old equipment.

Repair work

We repair a flashing lighting fixture in the following sequence:

1. We check the voltage in the electrical network and the quality of the contacts.
2. We replace the light bulb with a working one.
3. If the lamp continues to blink, we replace the starter in the EMPA lamps and check the choke. In the case of electronic ballasts, the electronic ballast will need to be repaired or replaced.

To perform repair work, you will need a certain set of tools, including a soldering iron, multimeter, and screwdrivers. It’s very good if, in addition to the tools, you have at least a basic set of knowledge in electrical engineering.

Electromagnetic ballast

To repair a device with electronic ballasts, perform the following steps:

1. Checking the capacitors. They are used to reduce electromagnetic interference and compensate for the lack of reactive power. In some cases, the malfunction is associated with current leaks in the capacitors. This reason must be eliminated first to avoid unnecessary replacement of a rather expensive capacitor.
2. We ring the electromagnetic ballast to find a breakdown. If the multimeter has an option for measuring inductance, use the characteristics of the inductor to look for an interturn short circuit. Rewinding ballast with your own hands is not worth the time spent - it is a very labor-intensive operation. In this regard, it is easier to change the ballast or install an electronic analogue. The required electronic ballast can be bought in a store or taken from a failed lamp.

Electronic ballast

Electronic ballast circuits differ depending on the manufacturer. However, the principle of their operation is no different from each other: the filaments are characterized by a certain inductance, which makes it possible to use them in a self-oscillating circuit. The circuit includes capacitors and coils and has feedback to an inverter consisting of powerful transistor switches.

When the threads heat up, their resistance increases and the vibration parameters change. The inverter's response is to provide voltage to ignite the light bulb. Current shunting occurs through the ionized gas medium of the voltage on the filaments, as a result of which the incandescence decreases. Feedback from the inverter to the self-oscillating circuit makes it possible to control the current strength in the light bulb.

To power the inverter, a diode rectifier is used, equipped with a filtering and interference overcoming system. A high-frequency inverter is one of the reasons why electronic ballasts are in high demand among consumers. Such a lamp does not blink at twice the mains frequency of 100 Hz, and operates almost silently (unlike electronic ballasts).

Electronic ballast repair

To diagnose the condition of electronic ballasts in a workshop, an oscilloscope, frequency generator or other measuring equipment is used. If the repair is carried out at home, the problem is found by visually inspecting the electronic board and sequentially searching for the damaged component using available measuring devices.

First, check the fuse (if there is one). A broken fuse is often the cause of lamp failure. This happens in the event of a power surge. The fuse blows due to improper operation of the ballast.

The cause of the malfunction can be almost any element of the ballast, including a capacitor, resistor, transistor, diodes, chokes and transformers. The problem is indicated by blackening of electronic components due to burnout.

The performance of the system is checked with a multimeter. To ensure a quality check, it is recommended to disassemble the system into parts by removing the necessary components from the board. When parts are together, false measurement results may occur. Without soldering, reliable indicators can only be obtained by testing.

Advice! When testing system elements, problems often arise with their identification. In this regard, it is recommended to obtain a device diagram before starting repairs.

Any faulty parts found should be replaced. Soldering semiconductors (diodes and transistors) must be done very carefully, since these components easily fail after overheating.

Note! Starting the electronic ballast without load is unacceptable. First, you should connect a fluorescent light bulb of suitable power to the ballast.