The electrical circuit of the fluorescent lamp. Connecting and repairing ballast for fluorescent lamps

Economical fluorescent lamps can work only with electronic ballasts. These devices are intended for current rectification. There is a lot of information about electronic ballast (circuit, repair and connection). However, first of all it is important to study the device device.

Diode type models

Models of diode type are currently considered budget. In this case, the transformers are used only downward type. Some transistor manufacturers install an open type. Due to this, the process of lowering the frequency in the circuit is not very sharp. Two capacitors are used to stabilize the output voltage.If we consider the modern models of ballasts, then there are dinistors of the operational type. Previously, they were replaced by conventional converters.

Two-contact models

This type of electronic ballast circuit differs from other models in that it uses a regulator. Thus, the user is able to adjust the output voltage parameter. Transformers are used in a variety of devices. If we consider common models, then there are installed lowering analogues. However, single-phase configurations are not inferior to them in terms of parameters.

In total, there are two capacitors in the circuit. Also, two-contact electronic ballast circuits include a choke that is installed behind the output channels. Transistors for models are suitable only capacitive. On the market, they are presented in both permanent and variable types. Fuses in devices are rarely used. However, if a thyristor is installed in the circuit for rectifying the current, then one cannot do without it.


Ballast "EPR" 18 W

This electronic ballast circuit for a fluorescent lamp includes as well as two pairs of capacitors.The transistor for the model provides only one. Negative resistance, he is able to withstand a maximum of 33 Ohms. For devices of this type, this is considered normal. Also, the 18 W electronic ballast circuit includes a choke located above the transformer. The dynistor is a modular type for current conversion. Lowering the clock frequency occurs with a tetrode. This element is located near the throttle.

Ballast "Epra" 2x18 W

The specified electronic ballast 2x18 (diagram is shown below) consists of output triodes, as well as a step-down transformer. If we talk about the transistor, then it is in this case provided an open type. There are two total capacitors in the circuit. Another scheme of electronic ballasts "Epr" 18 W has a choke, which is located under the transformer.

Condensers are standard installed near the channels. The conversion process is carried out by lowering the clock frequency of the device. The stability of the voltage in this case is ensured by a high-quality dinistor. In total, the model has two channels.


Ballast "Epra" 4x18 W

This electronic ballast 4x18 (diagram shown below) includes inverting capacitors. Their capacity is exactly 5 pF. In this case, the parameter of negative resistance in electronic ballasts reaches 40 ohms. It is also important to mention that the choke in the presented configuration is located under the dynistor. This model has one transistor. A transformer for the rectification of the current is applied down-type. Overload it is able to withstand large network. However, the fuse in the circuit is still installed.


Ballast Navigator

The electronic ballast Navigator (diagram shown below) includes a single junction transistor. Also, the difference of this model lies in the presence of a special regulator. With it, the user can adjust the output voltage parameter. If we talk about a transformer, it is provided in the circuit of a lowering type. It is located near the throttle and is fixed on the plate. The resistor for this model is chosen capacitive type.

In this case, there are two capacitors. The first one is located near the transformer. Its limiting capacity is 5 pF. The second capacitor in the circuit is located under the transistor.Its capacitance is equal to as much as 7 pF, and it can withstand a negative resistance maximum of 40 Ohms. Fuse in electronic ballasts is not used.


Electronic ballast transistor circuit EN13003A

The electronic ballast circuit for a fluorescent lamp with EN13003A transistors is quite common today. Models are produced, as a rule, without regulators and belong to the class of budget devices. However, the device can last for a long time, and they have fuses. If we talk about transformers, then they are suitable only for the lower type.

The transistor is installed in the circuit near the choke. The protection system for such models is mainly used standard. Device contacts are protected by dynistor. Also, the electronic ballast circuit at 13003 includes capacitors, which are often installed with a capacity of about 5 pF.

Use step-down transformers

An electronic ballast circuit for a fluorescent lamp with step-down transformers often includes voltage regulators. In this case, transistors are used, as a rule, open type.Many experts they are appreciated for high current conduction. However, a quality dinistor is very important for normal operation of the device.

For step-down transformers, operational analogs are often used. First of all, they are valued for their compactness, and for electronic ballasts this is a significant advantage. In addition, they are characterized by reduced sensitivity, and small network failures are not terrible for them.

The use of vector transistors

Vector transistors in electronic ballasts are used very rarely. However, in modern models, they still occur. If we talk about the characteristics of components, it is important to note that they are ways to keep negative resistance at 40 Ohms. However, they deal with overloads rather badly. In this case, the output voltage parameter plays a big role.

If we talk about transistors, then for these transformers they are suitable more orthogonal type. They cost the market quite expensive, but the power consumption of the models is extremely low. In this case, models with vector transformers are much less compact than competitors with lowering configurations.


Integrated Controller Chart

Electronic ballast for fluorescent lamps with an integral controller is quite simple. In this case, the transformers are used down-type. Directly capacitors in the system there are two. To reduce the limiting frequency, the model has a dynistor. The transistor is used in the electronic ballast of the operational type. Negative resistance it can withstand at least 40 ohms. Output triodes in models of this type are almost never used. However, the fuses are installed, and in case of network failures, they help a lot.

The use of low-frequency triggers

The trigger on the electronic ballast for fluorescent lamps is set in the case when the negative resistance in the circuit exceeds 60 Ohms. It removes the load from the transformer very well. The fuses are very rarely installed. Transformers for models of this type are used only vector. In this case, the lowering analogs are unable to cope with sharp jumps in the limiting clock frequency.

Directly dinistors in models are installed near the chokes. In terms of compactness, electronic ballasts are quite different.In this case, much depends on the used components of the device. If we talk about models with regulators, then they require a lot of places. They are also able to work in electronic ballasts for only two capacitors.

Models without regulators are very compact, but transistors for them can only be used of the orthogonal type. They differ in good conductivity. However, it should be borne in mind that these electronic ballasts on the market will be expensive for the buyer.

The classes, with a sufficient luminous flux and at the same time economical, prompted, one might even say, for some searches and a trial of options. At first I used the usual small lamp clothes peg, changed it to a small table luminescent lamp, then there was an 18 watt luminescent lamp “ceiling-wall” version of Chinese production. I liked the last one most of all, but the fixture of the lamp itself in the fixture was somewhat underestimated, literally by two or three centimeters, but “for complete happiness” they were not enough. I found a way out to do the same, but in my own way.Since the work of the existing electronic ballast did not cause any complaints, it was logical to repeat the scheme.

Principle scheme

This is a large part of this electronic ballasts, the choke and the capacitor from the Chinese are not included here.


Actually conscientiously drawn from the circuit board. The nominal of electronic components that allow this to be done was determined not only “by appearance”, but also with the help of measurements, with preliminary watering of the components from the board. In the diagram, the value of the resistors is indicated in accordance with the color marking. Only with respect to the throttle, he allowed himself not to unwind the existing for determining the number of turns, and measured the resistance of the wound wire (1.5 Ohm with a diameter of 0.4 mm) - it worked.


The first assembly on the circuit board. Component ratings picked up scrupulously, regardless of size and quantity, and was rewarded - the light came on the first time. Ferrite ring (10 x 6 x 4.5 mm) from an energy-saving light bulb, its magnetic permeability is unknown, the wire diameter of the coils on it is wound 0.3 mm (without insulation). The first start in the mandatory order through a 25W incandescent bulb. If it burns and the luminescent light initially blinks and goes out - increase (gradually) the value of C4,when everything worked and nothing suspicious was found, and removed the incandescent lamp, it reduced its nominal value to its original value.


To some extent, focusing on the PCB of the original source, I painted a signet for an existing suitable case and electronic components.


Rinse the handkerchief and assembled the scheme. Already anticipated a moment when I would be pleased with myself and glad to be. But, the circuit assembled on the PCB refused to work. I had to delve into and pick up resistors and capacitors. At the time of installation of the electronic ballast at the place of operation, the C4 had a capacity of 3n5, C5 - 7n5, R4 resistance of 6 Ohms, R5 - 8 Ohms, R7 - 13 Ohms.


The lamp "fit" not only in the design, the lamp lifted all the way up, made it possible to comfortably use the shelf inside the secretary's niche. Comfort in the "premises" suggested Babay.

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 supplying voltage, the electric field of which leads to gas breakdown, the appearance of a glow discharge and the appearance of an electric current in the circuit. The glow of a gas discharge of a pale blue hue is very weak in the visible light range.

But as a result of an electric discharge, most of the energy goes into the invisible, ultraviolet range, the quanta of which, getting into phosphorus-containing compounds (phosphor coatings) cause a glow in the visible region of the spectrum. Changing the chemical composition of the phosphor, get different colors of light: for fluorescent lamps (LDS) developed different shades of white, and for lighting for decorative purposes, you can choose a different color lamps. The invention and mass production of fluorescent lamps is a step forward compared with inefficient incandescent lamps.

What is ballast for?

The current in the gas discharge grows like an avalanche, which leads to a sharp drop in resistance. In order for the electrodes of the fluorescent lamp not to fail from overheating, an additional load is applied in series to limit the amount of current, the so-called ballast. Sometimes the term choke is used to refer to it.

Two types of ballast are used: electromagnetic and electronic. Electromagnetic ballast has a classic, transformer set: copper wire, metal plates.Electronic ballast uses electronic components: diodes, dinistors, transistors, microcircuits.

For the initial ignition (start) of a discharge in a lamp in electromagnetic devices, an additional starter is used. In the electronic version of the ballast, this function is implemented within a single electrical circuit. The device is lightweight, compact and unified by a single term - the electronic ballast apparatus (ECG). The massive use of electronic ballasts for fluorescent lamps due to the following advantages:

  • these devices are compact, have a small weight;
  • lamps turn on quickly, but smoothly;
  • the absence of flicker and noise from vibration, since the electronic ballast operates at a high frequency (tens of kHz) in contrast to the electromagnetic, operating from a mains voltage with a frequency of 50 Hz;
  • decrease in heat losses;
  • electronic ballast for fluorescent lamps has a power factor value of up to 0.95;
  • the presence of several, proven types of protection that increase the safety of use and extend the service life.

Electronic ballasts for fluorescent lamps

An electronic ballast is an electronic card packed with electronic components. The schematic diagram of the connection (Fig. 1) and one of the variants of the ballast circuit (Fig. 2) are shown in the figures.


Fluorescent lamp, C1 and C2 - capacitors


Electronic ballasts may have different circuit solutions depending on the used components. Voltage rectification is performed by diodes VD4 – VD7 and then filtered by capacitor C1. After the supply voltage starts charging the capacitor C4. At a level of 30 V, the dynistor CD1 breaks through and the T2 transistor opens, then the oscillator switches on at T1, T2 and TR1. The resonant frequency of the series circuit of the capacitors C2, C3, the inductor L1 and the generator are close in magnitude (45-50 kHz). The resonance mode is necessary for the stable operation of the circuit. When the voltage on the capacitor C3 reaches the start value, the lamp lights up. This reduces the regulating frequency of the generator and voltage, and the choke limits the current.



Repair of electronic ballasts


If there is no possibility of a quick replacement of the failed electronic ballast, you can try to repair the ballast itself.To do this, select the following sequence of actions to eliminate the problem:

  • to begin to check the integrity of the fuse. This breakdown often occurs due to overload (overvoltage) in a 220 volt network;
  • Next, a visual inspection of electronic components: diodes, resistors, transistors, capacitors, transformers, chokes;
  • in case of detection of the characteristic blackening of the part or board, repair is performed by replacing it with a serviceable element. How to check with your own hands a faulty diode or transistor, having a common multimeter in stock, is well known to any user with a technical background;
  • it may be that the cost of parts for replacement will be higher or comparable to the cost of a new electronic ballast. In this case, it is better not to waste time on repairs, but to pick up a replacement that is close in parameters.

ECG for compact LDS

Relatively recently, fluorescent energy-saving lamps, adapted to standard cartridges for simple incandescent lamps - E27, E14, E40, have become widely used in everyday life. In these devices, electronic ballasts are inside the cartridge, so the repair of these electronic ballasts is theoretically possible, but in practice it is easier to buy a new lamp.

The photo shows an example of such a lamp brand OSRAM, with a capacity of 21 watts. It should be noted that at present, the position of this innovative technology is gradually occupied by similar lamps with LED sources. Semiconductor technology, continuously improving, allows you to quickly reach the price of LDS, the cost of which remains almost unchanged.


T8 fluorescent lamps

T8 lamps have a glass bulb diameter of 26 mm. The widely used lamps T10 and T12 have diameters of 31.7 and 38 mm, respectively. For fixtures usually used LDS 18 watts. T8 lamps do not lose their performance at power supply surges, but when the voltage drops below more than 10%, ignition of the lamp is not guaranteed. The ambient temperature also affects the reliability of the LDS T8. At subzero temperatures, the luminous flux decreases, and failures can occur in the ignition of the lamps. T8 lamps have a lifespan of 9,000 to 12,000 hours.

How to make a lamp with your own hands?

You can make the simplest lamp of two lamps as follows:

  • choose suitable for the color temperature (shade of white) lamps of 36 W;
  • we make the case of a material that does not ignite. You can use the case from the old lamp.We select electronic ballasts for this power. The marking should be 2 x 36;
  • we select 4 bullets with G13 markings (the gap between the electrodes is 13 mm), the installation wire and the self-tapping screws;
  • cartridges must be mounted on the body;
  • the installation location of the electronic ballast is chosen from considerations of minimizing the heat from operating lamps;
  • cartridges are connected to the base LDS;
  • To protect the lamps from mechanical impact, it is desirable to install a transparent or matte protective cap;
  • the lamp is fixed on the ceiling and is connected to the 220 V power network.


Ballast for a discharge lamp (fluorescent light sources) is used to ensure normal operating conditions. Another name is the ballast. There are two options: electromagnetic and electronic. The first of them differs in a number of disadvantages, for example, noise, the effect of the flickering of a fluorescent lamp.

The second type of ballast eliminates many drawbacks in the work of the light source of this group, and therefore more popular. But failures in such devices also happen. Before throwing out, it is recommended to check the elements of the ballast circuit for faults.It is quite possible to independently perform the repair of electronic ballasts.

Varieties and principles of operation

The main function of electronic ballasts is to convert AC to DC. In a different way, electronic ballast for discharge lamps is also called a high-frequency inverter. One of the advantages of such devices - compactness and, accordingly, low weight, which further simplifies the work of fluorescent light sources. And also electronic ballasts do not create noise at work.

The electronic type ballast, after being connected to a power source, provides rectification of the current and heating of the electrodes. In order for the fluorescent lamp to light up, a voltage of a certain magnitude is applied. The current is set in automatic mode, which is realized by means of a special regulator.

This possibility eliminates the possibility of flicker. The last stage - there is a high voltage pulse. Ignition of the fluorescent lamp is carried out for 1.7 s. If the start of the light source has a failure, the body of the heat instantly fails (burns out). Then you can try to make repairs with your own hands, which requires opening the case.The circuit of electronic ballast looks like this:


The main elements of electronic ballasts of fluorescent lamps: filters; directly rectifier itself; converter; throttle. The circuit also provides protection from power supply surges, which eliminates the need for repair for this reason. And, in addition, the ballast for discharge lamps implements the function of power factor correction.

By purpose, the following types of electronic ballasts are encountered:

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

ECGs for fluorescent lamps are divided into groups that are different in functionality: analog; digital; standard.

Connection diagram, launch

The control gear is connected on the one hand to the power source, on the other - to the lighting element. It is necessary to provide for the installation and mounting of electronic ballasts. The connection is made according to the polarity of the wires. If you plan to install two lamps through ballasts, use the parallel connection option.

The scheme will look like this:


The group of gas-discharge fluorescent lamps can not operate normally without a control gear.Its electronic version of the design provides 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 lamp operation is carried out in three stages: heating of the electrodes, the appearance of radiation as a result of a high-voltage pulse, and the maintenance of combustion is carried out by means of a constant supply of voltage of small magnitude.

Breakdown detection and repair work

If problems are observed in the operation of gas-discharge lamps (flickering, no light), you can make repairs yourself. But first you need to understand what the problem is: in the ballast or the lighting element. To check the operation of the electronic ballast, a linear light bulb is removed from the luminaires, the electrodes are closed, and a standard incandescent lamp is connected. If it caught fire, the problem is not in the ballast.

Otherwise, you need to look for the cause of breakage inside the ballast. To determine the malfunction of fluorescent lamps, you need to "ring" all the elements in turn. Start with the fuse.If one of the circuit nodes fails, it is necessary to replace it with an analogue. Parameters can be seen on the burned item. Repair of ballast for gas-discharge lamps requires the use of skills in owning a soldering iron.

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

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

Repair of compact fluorescent lamps is performed on a similar principle: first, the housing is disassembled; the filaments are checked, the cause of the breakdown on the control board is determined. Often there are situations when the ballast is fully functional, and the filament burned out. It is difficult to fix the lamp in this case.If the house has another broken light source of a similar model, but with an intact body glow, you can combine the two products into one.

Thus, ECG is a group of advanced devices that ensure the effective operation of fluorescent lamps. If the flickering of a light source was noticed or it doesn’t turn on at all, checking the ballast and its subsequent repair will prolong the life of the light bulb.

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