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 a breakdown of the gas, the appearance of a glow discharge and the appearance of an electric current in the circuit. The glow of the gas discharge is of a pale blue hue, 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. By changing the chemical composition of the phosphor, different colors of glow are obtained: various shades of white have been developed for fluorescent lamps (LDS), and lamps of a different color can be chosen for decorative lighting. The invention and mass production of fluorescent lamps is a step forward in comparison with low-efficiency incandescent lamps.
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 due to overheating, an additional load is switched on in series, limiting the amount of current, the so-called ballast. Sometimes the term choke is used to refer to it.
Two types of ballasts are used: electromagnetic and electronic. The electromagnetic ballast has a classic, transformer configuration: copper wire, metal plates. In electronic ballasts (electronic ballast) electronic components are used: diodes, dinistors, transistors, microcircuits.
Incandescent lamps
For the initial ignition (start) of the discharge in the lamp in electromagnetic devices, an additional starting device is used - a starter. In the electronic version of the ballast, this function is implemented within a single electrical circuit. The device turns out to be light, compact and is united by a single term - an electronic ballast (electronic ballast). The mass use of electronic ballasts for fluorescent lamps is due to the following advantages:
Electronic ballast is an electronic board filled with electronic components. Schematic diagram of inclusion (Fig. 1) and one of the variants of the ballast scheme (Fig. 2) are shown in the figures.
Fluorescent lamp, C1 and C2 - capacitors
Electronic ballast circuit
Electronic ballasts may have different circuit solutions depending on the components used. The voltage is rectified by diodes VD4-VD7 and then filtered by capacitor C1. After the voltage is applied, the charging of the capacitor C4 begins. At a level of 30 V, the dinistor CD1 breaks through and the transistor T2 opens, then the oscillator on transistors T1, T2 and the transformer TR1 is turned on. The resonant frequency of the series circuit of capacitors C2, C3, 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 across capacitor C3 reaches the start value, the lamp lights up. This reduces the control frequency of the generator and voltage, and the inductor limits the current.
Photo of the internal device of the electronic ballast
Photo of a typical electronic ballast
If it is not possible to quickly replace a failed electronic ballast, you can try to repair the ballast yourself. To do this, select the following sequence of actions to troubleshoot:
Relatively recently, fluorescent energy-saving lamps have become widely used in everyday life, adapted to standard cartridges for simple incandescent lamps - E27, E14, E40. In these devices, the electronic ballasts are inside the cartridge, so repairing these electronic ballasts is theoretically possible, but in practice it is easier to buy a new lamp.
The photo shows an example of such an OSRAM lamp with a power 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 virtually unchanged.
OSRAM lamp with E27 base
T8 lamps have a glass bulb diameter of 26 mm. The commonly used T10 and T12 lamps have diameters of 31.7 and 38 mm respectively. For lamps, LDS with a power of 18 watts is usually used. T8 lamps do not lose performance during power surges, but if the voltage drops by more than 10%, lamp ignition is not guaranteed. The ambient temperature also affects the reliability of the LDS T8. At sub-zero temperatures, the luminous flux decreases, and failures in the ignition of the lamps may occur. T8 lamps have a life span of 9,000 to 12,000 hours.
You can make a simple lamp from two lamps as follows:
The simplest lamp of two lamps
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When the ballast for fluorescent lamps (LL) fails, the lighting fixture stops functioning correctly. To return it to normal mode can only be a quick replacement of the damaged element with a serviceable one.
You can buy the part in a specialized store. The main thing is to choose the module of the correct modification, corresponding in power and other parameters to the existing lamp.
A fluorescent lamp is a practical and economical module designed to organize lighting systems in domestic, industrial and technical premises.
The only difficulty is that it is not possible to directly connect the device to centralized power supply communications.
Electromagnetic ballast consumes about 25% of the power of the lighting device, thus reducing its efficiency and efficiency level by a quarter
This is due to the fact that the creation of a stable activating discharge in fluorescent lamps and the subsequent limitation of the increasing current require the organization of some specific physical conditions. It is these problems that the installation of a ballast device solves.
The ballast is a device that regulates starting functions and connects fluorescent lighting devices to electrical communications.
It is used to maintain the correct mode of operation and effectively limit the operating current.
It acquires increased relevance when there is insufficient electrical load in the network and there is no necessary limitation on current consumption.
Inside the fluorescent lamps is an electrically conductive gaseous medium with negative resistance. This is manifested in the fact that with an increase in current between the electrodes, the voltage decreases significantly.
Compensates for this moment and ensures the correct operation of the lighting device, a ballast connected to the control system.
When a large amount of current is supplied to any luminescent device, it can fail. To prevent this from happening, a ballast is included in the design of the lamp, which acts as a converter.
It also increases the overall voltage for a short period and helps the luminescents to light up when there is not enough resource for this in the central network. Additional functions of the module vary depending on its design features and type of execution.
Today, electromagnetic and electronic ballast devices are the most widespread. They work reliably and provide long-term correct functioning and comfortable operation of fluorescent lamps of all types. They have the same general principle of operation, but differ somewhat in individual capabilities.
Electromagnetic type ballasts are used for lamps connected to the central electrical network using a starter.
The supply of voltage in this embodiment is accompanied by a discharge, followed by intense heating and closing of the bimetallic electrode elements.
Electromagnetic ballast differs from electronic one even in appearance. The first has a more massive, high design, and the second is an elongated thin board, on which all the working elements are located.
At the moment when the starter electrodes close, the operating current increases sharply. This is due to the limitation of the maximum resistance of the choke coil.
After the starter has completely cooled down, the bimetallic electrodes open.
If the starter fails in the design of the electromagnetic ballast, a false start appears in the operation of the luminescent. At the same time, at the moment of switching on, the lamp flashes 3-4 times and only then starts to burn. This leads to the consumption of excess energy and significantly reduces the overall working life of the light source.
When the luminescent circuit is opened by the starter, an active high voltage pulse is immediately formed in the induction coil and the lighting device is ignited.
The advantages of the device include:
In addition to positive aspects, users note an extensive list of disadvantages that spoil the overall impression of the device.
Among them are such positions as:
When buying, all these conditions must be taken into account in order to understand what the operation of a household lighting system equipped with fluorescents will cost in the future.
The electronic type ballast is used for the same purposes as the electromagnetic module. However, structurally and according to the principle of performing their duties, these devices differ significantly from each other.
Cheap electronic ballast, has a simple self-oscillating circuit with a transformer and a basic output stage operating on bipolar transistors. A big minus of these devices is the lack of protection against abnormal operating conditions.
Widespread popularity came to products in the early 90s. At this time, they began to be used in combination with a variety of light sources.
Initially, the manufacturers compensated for the high cost compared to electromagnetic products with the good efficiency of the devices and other useful characteristics and properties.
The use of electronic ballasts made it possible to reduce the total consumption of electrical energy by 20-30%, while maintaining full saturation, power and strength of the light flux.
This effect was achieved by increasing the base light output of the lamp itself at an increased frequency and a significantly higher efficiency of electronic modules compared to electromagnetic ones.
The most vulnerable elements of the electronic ballast are the fuse (1), capacitor (2) and transistors (3). It is they who usually fail for various objective reasons and lead the lamp to an inoperative state.
The soft start and gentle operating mode made it possible to extend the life of the luminescents by almost half, thus reducing the overall operating costs of the lighting system. Lamps needed to be changed much less often, and the need for starters disappeared altogether.
In addition, with the help of electronic ballasts, it was possible to get rid of working background noise and pronounced annoying flicker, while simultaneously achieving stable and uniform illumination of the premises even with mains voltage fluctuations in the range of 200-250 V.
To prevent the fluorescent lamp from buzzing and flickering, it is necessary to feed it only with high-frequency current of 20 kHz or more. To implement this task, the switching circuit must include a rectifier, a high-voltage RF generator and a ballast that plays the role of a switching power supply
Additionally, it became possible to control the brightness of the lamp, adjusting the light flux to the individual desires and needs of the user.
Among the main advantages of the products, the following criteria stood out:
Some manufacturers complete their electronic ballasts with a special fuse. It protects devices from power surges, fluctuations in the central network and erroneous activation of a lamp without a lamp.
Today, labor protection authorities recommend that, in order to improve working conditions and increase productivity, equip fluorescent lamps installed in office premises with electronic rather than electromagnetic starting devices.
Of the minuses of electronic products, only the cost is usually mentioned, which is much higher compared to electromagnetic modules. However, this may only matter at the time of purchase.
In the future, in the process of intensive operation, the electronic ballast will fully work out its price and even begin to bring benefits, seriously saving the electrical resource and removing part of the load from the light source.
Compact fluorescent lamps are similar to traditional incandescent lamps with E14 and E27 screw base.
They can be placed in modern and rare chandeliers, sconces, floor lamps and other lighting fixtures.
Due to the design features of compact fluorescents, increased requirements are imposed on the electronic "stuffing". Brands always take them into account in production, and unknown manufacturers, in order to reduce the cost, change many elements to simpler ones. This significantly reduces the efficiency and service life of the module.
Devices of this class are completed, as a rule, with a progressive electronic ballast, which is built directly into the internal structure and is usually located on the lamp product board.
When choosing a ballast for a fluorescent lamp, it is first necessary to pay attention to such a parameter as the power of the module.
It must fully match the power of the lighting device, otherwise the lamp simply will not be able to fully function and produce a light flux in the required mode.
It is strictly forbidden to connect the ballast to the network without load. The device may burn out immediately and you will have to repair it or buy a new one.
True, such devices are considered obsolete, have bulky dimensions and consume additional energy. This significantly reduces their attractiveness, even despite the affordable initial price.
To check the health of the electronic ballast, a special measuring device is useful - a pocket oscilloscope
Electronic devices are much more expensive. This point is especially true for products produced by cool branded manufacturers. But their price is more than offset by energy efficiency, practicality, flawless assembly and a high level of overall quality of devices.
The manufacturing plant is another significant criterion when buying. You should not focus solely on the price and purchase the cheapest model of all that are offered in the store.
An unnamed Chinese-made product can fail very quickly and lead to subsequent problems with the operation of the light bulb itself and even the lamp.
Brand manufacturers complete ballasts with high-quality, wear-resistant parts that ensure the correct operation of the module throughout the entire operational period.
It is better to give preference to brands with a reliable reputation, which have proven themselves for a long time in the market of lighting equipment and related items.
Such devices will reliably work out the entire prescribed period, ensuring the full functioning of the luminescent in any lighting fixture.
The ballast products, produced by the enterprises of popular brands specializing in the manufacture of electrical equipment and related components, have a strong and durable outer casing made of a heat-resistant, non-deforming plastic compound.
The IP2 marking on the products indicates that the device has a good level of overall protection and is protected from foreign parts larger than 12.5 mm inside the box.
The operation of the device is comfortable and absolutely safe. The design completely eliminates the possibility of user contact with conductive elements.
Ballast modules marked IP2 are reliable, practical and convenient for domestic use, however, they are vulnerable to dust penetration. Because of this small minus, it is not advisable to put them in lamps illuminating dusty work areas.
The normal temperature range for effective and continuous operation of the device is quite wide.
Branded ballasts cope well with their tasks in frosts down to -20 °C and feel great on hot days when the air heats up to +40 °C.
Electromagnetic ballast devices manufactured under the E.Next brand are very popular with customers.
This is due to the fact that the company offers truly high-quality, reliable and progressive modules, made at the highest level in strict accordance with the requirements for equipment of this class.
In addition to warranties and maintenance, E.Next offers customers custom technical support through call centers. By calling there, the consumer can ask the operator a question of any complexity and receive a professional, understandable answer within a few minutes.
The company gives a company guarantee for all products and offers customers high-quality service at all stages of cooperation.
Equally in demand are electromagnetic ballasts created by a well-known and respected European manufacturer of electrical equipment and related items - Philips.
Products of this brand are considered one of the highest quality, reliable and efficient.
Electromagnetic modules from Philips are presented on the market in the widest range. Finding the right option for a lamp of any configuration is not difficult
Philips ballasts help save energy and neutralize the load that occurs during the operation of fluorescent lamps.
Products of electronic type belong to the modern type of equipment and, in addition to traditional ones, also have additional functions. In this segment, the leading positions are occupied by products from the German company Osram.
Their cost is slightly higher than that of Chinese or domestic counterparts, but significantly lower compared to competitors such as Philips and Vossloh-Schwabe.
Osram electronic ballasts have a number of advantages. They have a neat shape and modest dimensions, can operate in a temperature range of -15 ... +50 ° C and reliably serve for 100,000 hours.
Among the budget branded modules, Horos electronic ballasts clearly stand out against the background of competitors.
Despite the loyal cost, these items demonstrate high working efficiency and a good level of efficiency, eliminate the ignition delay, reduce energy consumption to a minimum and increase the light output of the lamp itself.
With the help of these tools, annoying flickering in fluorescent lamps can be eliminated and lighting fixtures can be made as convenient and comfortable as possible.
The young, promisingly developing company Feron does not lag behind the venerable old-timers of the market. It offers users European-level products at a very small, reasonable price.
Feron ballasts are carefully made. All details have certificates of conformity. The outer case, made of plastic, is an elongated flat rectangle. The product weighs little and is easily mounted in fluorescent light sources of any configuration.
Ballast-type devices from Feron protect the lamps from unexpected electromechanical interference and voltage drops, eliminate eye-irritating flicker and help save more than 30% of electrical energy.
Feron's ballast-controlled luminescent turns on/off instantly. There is no background sound effect during operation. The lighting is soft, even and creates a pleasant, calm atmosphere around.
How does an electronic device work in a fluorescent lamp. Detailed description of the device and the principle of operation of the product:
What is the difference between electromagnetic and electronic ballasts. Features of each of the modules and the specific nuances of their use in household lighting fixtures:
Features of the operation of luminaires equipped with different types of ballasts. Which elements are more effective and why. Practical recommendations and useful tips from the personal experience of the master:
To choose the right ballast for household fluorescent lamps, you need to know how this element works and what function it performs. Having such information, as well as understanding the varieties of the device, it will be possible to acquire the desired modification without any difficulties.
The cost of the module depends on the manufacturer, but even branded products have a completely loyal price and do not cause damage to the budget of the average consumer.
sovet-ingenera.com
Ballast for gas discharge lamp (fluorescent light sources) is used to ensure normal working conditions. Another name is a ballast (PRA). 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.
The second type of ballast eliminates many 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 independently repair the electronic ballast.
The main function of electronic ballasts is to convert alternating current to direct current. In another way, the 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 type ballast, after being connected to a power source, provides current rectification and heating of the electrodes. In order for a fluorescent lamp to light up, a certain voltage is applied. The current is adjusted automatically, which is implemented by means of a special regulator.
This feature eliminates the possibility of flickering. The last stage is a high-voltage impulse. Ignition of a fluorescent lamp is carried out in 1.7 s. If a failure occurs when starting the light source, the filament instantly fails (burns out). Then you can try to make repairs with your own hands, for which you need to open 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 surges, which eliminates the need for repairs for this reason. And, in addition, the ballast for gas discharge lamps implements the function of power factor correction.
According to the intended purpose, the following types of electronic ballasts are found:
Electronic ballasts for fluorescent lamps are divided into groups that differ in functionality: analog; digital; standard.
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 fixing electronic ballasts. The connection is made in accordance with the polarity of the wires. If you plan to install two lamps through the gear, use the option of parallel connection.
The schema will look like this:
A group of gas-discharge fluorescent lamps cannot work normally without a ballast. Its electronic version of the design provides a soft, but at the same time almost instantaneous start of the light source, which further prolongs its service life.
The lamp is ignited and maintained in three stages: heating of the electrodes, the appearance of radiation as a result of a high-voltage pulse, and maintaining combustion is carried out by means of a constant supply of a small voltage.
If there are problems in the operation of gas-discharge lamps (flickering, no glow), you can make repairs yourself. But first you need to understand what the problem is: in the ballast or in the lighting element. To check the operability of electronic ballasts, a linear light bulb is removed from the fixtures, the electrodes are closed, and a conventional 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 breakdown inside the ballast. To determine the malfunction of fluorescent lamps, it is necessary to “ring out” all the elements in turn. Start with the fuse. If one of the nodes of the circuit is out of order, it is necessary to replace it with an analogue. The parameters can be seen on the burnt element. Ballast repair for gas discharge lamps requires the use of soldering iron skills.
If everything is in order with the fuse, then you should check the capacitor and diodes that are installed in close proximity to it for serviceability. The voltage of the capacitor must not be below a certain threshold (this value varies for different elements). If all the elements of the control gear are in working order, without visible damage, and the ringing also did not give anything, it remains to check the inductor winding.
In some cases, it is easier to buy a new lamp. It is advisable to do this in the case when 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 body is disassembled; the filaments are checked, the cause of the breakdown on the control gear board is determined. Often there are situations when the ballast is fully functional, and the filaments are burned out. Repairing the lamp in this case is difficult to produce. If the house has another broken light source of a similar model, but with an intact glow body, you can combine two products into one.
Thus, electronic ballasts represent a group of advanced devices that ensure the efficient operation of fluorescent lamps. If the light source flickers or does not turn on at all, checking the ballast and its subsequent repair will extend the life of the bulb.
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Continuing on the topic of repairing fixtures, it will be useful for many to know not only how to check a fluorescent lamp, but also how to check the ballast of a fluorescent lamp. For a quick check, you need a minimum of devices: a control light, a wire, a couple of paper clips, as well as a few minutes of free time.
To begin with, it is necessary to present a diagram of the electronic ballast of a fluorescent lamp and add a control light (indicated by red lines) to its design.
The schemes of most fixtures are almost identical to each other, differ only in minor changes.
In general, before checking the electronic ballast for fluorescent lamps, you need to remove the tube, then short-circuit the leads of the filaments, and then connect a regular 220 V incandescent bulb of low power between them.
Attention! To avoid failure of the electronic components of the ballast, it is not recommended to connect the circuit without load to the network, i.e. without light bulb.
For simple fixtures, it is very convenient to use a paper clip, it reliably closes the contacts going to the tube.
After all the manipulations, such a design can be included in the network. The working ballast will be able to supply voltage to the light bulb, and as you can see from the photo, it will glow.
If the ballast was repaired with your own hands, and it is necessary to check its performance, it is best to connect another light bulb in series with the lamp. In case of errors made in the work, or a short circuit, this light will glow brightly, and the components of the circuit will not fail.
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An electronic ballast is a device that turns on fluorescent lamps. Models differ from each other in terms of rated voltage, resistance and overload. Modern devices are able to work in an economical mode. Ballasts are connected via controllers. As a rule, they are applied electrode type. Also, the connection diagram of the model involves the use of an adapter.
Electronic ballast circuits for fluorescent lamps include a set of transceivers. The contacts of the models are of the switched type. A typical device consists of capacitors up to 25 pF. Regulators in devices can be used operational or conductor type. Stabilizers in ballasts are installed through the lining. To maintain the operating frequency, the device has a tetrode. The inductor in this case is attached through a rectifier.
Electronic ballast (circuit 2x36) of low efficiency is suitable for 20 W lamps. The standard scheme includes a set of expansion transceivers. Their threshold voltage is 200 V. The thyristor in devices of this type is used on the lining. The comparator fights overloads. Many models use a converter that operates at a frequency of 35 Hz. A tetrode is used to increase the voltage. Additionally, adapters are used to connect ballasts.
The electronic ballast (the connection diagram is shown below) has one transistor with an output to the plate. The threshold voltage of the element is 230 V. For overloads, a comparator is used, which operates at low frequencies. These devices are well suited for lamps up to 25 watts. Stabilizers are often used with variable transistors.
Many circuits use converters, and their operating frequency is 40 Hz. However, it can increase with increasing overloads. It is also worth noting that ballasts use dinistors to rectify the voltage. Regulators are often installed behind transceivers. Operating taxes issue a frequency of no more than 30 Hz.
Electronic ballast (2x36 circuit) for 15 W lamps is assembled with integrated transceivers. Thyristors in this case are mounted through a choke. It is also worth noting that there are modifications on open adapters. They are distinguished by high conductivity, but operate at low frequency. Capacitors are only used with comparators. The rated voltage during operation reaches 200 V. Insulators are used only at the beginning of the circuit. Stabilizers are used with a variable regulator. The conductivity of the element is at least 5 microns.
The circuit diagram of the electronic ballast for 20 W lamps implies the use of an expansion transceiver. Transistors are commonly used in different capacities. At the beginning of the circuit, they are set to 3 pF. For many models, the conductivity index reaches 70 microns. In this case, the sensitivity coefficient is not significantly reduced. The capacitors in the circuit are used with an open regulator. The lowering of the operating frequency is carried out through a comparator. In this case, the rectification of the current occurs due to the operation of the converter.
If we consider circuits on phase transceivers, then there are four capacitors. Their capacitance starts at 40 pF. The operating frequency of the ballast is maintained at 50 Hz. Triodes for this are used on operational regulators. To reduce the sensitivity factor, various filters can be found. Rectifiers are quite often used on linings and are installed behind the throttle. The conductance of the ballast primarily depends on the threshold voltage. The type of regulator is also taken into account.
Electronic ballast (2x36 circuit) for 36 W lamps has an expansion transceiver. The device is connected via an adapter. If we talk about the performance of ballasts, then the rated voltage is 200 watts. Insulators for devices are suitable for low conductivity.
Also, the 36W electronic ballast circuit includes capacitors with a capacity of 4 pF. Thyristors are often installed behind filters. To control the operating frequency there are regulators. Many models use two rectifiers. The operating frequency for ballasts of this type is maximum 55 Hz. In this case, the overload can increase significantly.
The electronic ballast T8 (circuit shown below) has two low conductance transistors. The models use only contact thyristors. Capacitors at the beginning of the circuit are of high capacity. It is also worth noting that ballasts are produced on contactor stabilizers. Many models support high voltage. The heat loss coefficient is about 65%. The comparator is set with a frequency of 30 Hz and a conductivity of 4 microns. The triode for it is selected with a lining and an insulator. The device is switched on via an adapter.
The electronic ballast (2x36 circuit) with MJE13003A transistors includes only one converter, which is located behind the throttle. The models use a variable type contactor. The operating frequency of the ballasts is 40 Hz. In this case, the threshold voltage during overloads is 230 V. The triode is used in devices of the pole type. Many models have three rectifiers with a conductivity of 5 microns. The disadvantage of the device with transits MJE13003A can be considered high heat losses.
Ballasts with these transistors are valued for good conductivity. They have a low heat loss coefficient. The standard device circuit includes a wire converter. The throttle in this case is used with a lining. Many models have low conductivity, but the operating frequency is 30 Hz. Comparators for modifications are selected on a wave capacitor. Regulators are only suitable for operating type. In total, the device has two relays, and contactors are installed behind the throttle.
The ballast on the KT8170A1 transistor consists of two transceivers. The models have three filters for impulse noise. The rectifier is responsible for turning on the transceiver, which operates at a frequency of 45 Hz. Models use only variable-type converters. They operate at a threshold voltage of 200 V. These devices are excellent for 15 W lamps. Triodes in controllers are used as output type. The overload indicator may vary, and this is primarily due to the relay capacity. You also need to remember about the capacitance of the capacitors. If we consider wired models, then the above parameter for the elements should not exceed 70 pF.
Schematic diagram of the electronic ballast on transistors KT872A involves the use of only variable converters. The bandwidth is about 5 microns, but the operating frequency may vary. The transceiver for ballast is selected with an expander. Many models use several capacitors of different capacities. At the beginning of the chain, elements with plates are used. It is also worth noting that the triode is allowed to be installed in front of the inductor. Conductivity in this case will be 6 microns, and the operating frequency will not be higher than 20 Hz. At a voltage of 200 V, the overload at the ballast will be about 2 A. To solve problems with reduced sensitivity, stabilizers on expanders are used.
An electronic ballast (2x36 circuit) with single-pole dinistors is capable of operating at an overload of more than 4 A. The disadvantage of such devices is a high heat loss coefficient. The modification scheme includes two low conductivity transceivers. For models, the operating frequency is about 40 Hz. The conductors are attached behind the throttle, and the relay is installed only with a filter. It is also worth noting that the ballasts have a conductive transistor.
Capacitor is used low and high capacitance. At the beginning of the circuit, 4 pF elements are used. The resistance in this section is about 50 ohms. It is also necessary to pay attention to the fact that insulators are used only with filters. The threshold voltage for ballasts when turned on is approximately 230 V. Thus, the models can be used for lamps of different power.
Bipolar dinistors primarily provide high conductivity for the elements. Electronic ballast (2x36 circuit) is made with components on switches. In this case, the regulators are used operational type. The standard circuit of the device includes not only a thyristor, but also a set of capacitors. The transceiver is used in this case of a capacitive type, and it has a high conductivity. The operating frequency of the element is 55 Hz.
The main problem of devices is low sensitivity at high overloads. It is also worth noting that triodes can only operate at an increased frequency. Thus, the lamps often flash, and this is caused by overheating of the capacitors. To solve this problem, filters are installed on the ballasts. However, they are not always able to cope with overloads. In this case, it is worth considering the amplitude of the jumps in the network.
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Fluorescent lamps have some disadvantages that become noticeable after turning on the light. A strong buzz and frequent flickering of light, observed during the operation of such built-in lamps, can unsettle any person. The only solution to this problem is to install a special ballast called electronic ballast.
The production of fluorescent lamps was conceived for the development of lighting systems using conventional incandescent lamps, which had an extremely short service life. The maximum service life of an incandescent lamp is about two thousand hours, which cannot be compared with the durability of fluorescent lamps, which has more than 16 thousand hours. In addition, fluorescent lamps have a good luminous flux, which exceeds the light from conventional lamps by more than six times.
An electronic ballast is a special product that automatically starts fluorescent lamps and keeps them running for a long time. The production of EMPRA began three decades ago. They were supposed to replace large ballasts. Experts attribute this to the fact that the old ballasts had a lot of shortcomings that greatly complicated their use.
List of major disadvantages such:
New EMPRA for LED lamp, purchased at any store, is the following components:
And also the inverter is often equipped with a device that is responsible for the smooth regulation of the brightness of the light of the LED lamp.
Fluorescent lamp equipped with electronic ballast, begins to work, passing through several main stages.
A special rectifier, which is responsible for converting DC to AC voltage, transfers it to the buffer of a powerful capacitor. Further, this voltage passes further and appears on the half-bridge inverter. At this time, all capacitors and small voltage microcircuits are charged.
When the voltage value reaches 7 volts, the microcircuit begins to be deliberately dropped, and then the control capacitor is charged, which is regulated by several transistors. When the voltage reaches 12 volts, the elements of the fluorescent lamp heat up quickly.
When the current moves in the product, the decrease in the maximum oscillation frequency immediately begins, and the voltage value increases. The fluorescent lamp warms up in just a few seconds, if you start counting from the moment the voltage is applied to the product. In this case, the electronic ballast plays the role of a systematizer, because it does not allow the lamp to start without going through the preparatory warm-up stage. This will help to avoid many problems in the operation of the lamp.
The values of the indicators of the half-bridge, for example, its amplitude, are reduced to their minimum. In order for a fluorescent lamp to light up, a voltage of about 620 volts is required. Otherwise, it simply won't work. A special choke is able to significantly exceed this value, increasing the voltage in the electrical network, which subsequently leads to the ignition of the lamp. This whole process usually takes about a few seconds.
Due to the operation of the electronic ballast, the current strength does not exceed the optimal value for the quality of the lamp. The electronic ballast fully controls the switching amplitude of the half-bridge, thus ensuring stable operation of the luminaire.
First you need to carefully disassemble the fluorescent lamp. Next, it is worth removing obsolete product components from it. This is, first of all, a choke, various capacitors, a starter and other elements. Only fluorescent lamps, wire harnesses and electronic ballasts should be left in the luminaire.
Absolutely anyone with minimal knowledge of the operation of electrical circuits is capable of making an electronic ballast connection. Of course, that people who do not have experience in this area should not even try, but should contact an experienced electrician.
To connect the electronic ballast, you will need the following tools and materials:
Before assembling the circuit, it is necessary to determine the location of the electronic ballast product inside the fluorescent lamp. In this case, it is worth considering the length of absolutely all wires and the availability of convenient access to the desired control system. That is why it is worth making a hole in the luminaire housing in advance, where it is possible to install electronic ballasts using fastening materials. Next, you need to connect the electronic ballast to the lamp connectors. There is another equally important point, which is that the power of the electronic ballast must be several times greater than that of a fluorescent lamp.
As soon as the process of correct assembly of the fluorescent lamp with the electronic ballast is completed, it is necessary to install it in the right place. First, it is worth checking with a multimeter all the wires that stick out of the wall for the presence of operating voltage in them. When it is absent, then you need to connect all the contacts to the equipment. After all these actions, it is worth doing a test run of a luminaire equipped with electronic ballast. In the case when all actions were successful, then the fluorescent lamps must light up simultaneously, without an additional warm-up process, and the emitted light should not flicker frequently.
Experienced electricians identify several main advantages of using electronic ballasts in the operation of fluorescent lamps. First of all, they include:
The main disadvantage of using electronic ballasts is, like other latest technologies and products, a very high cost compared to other similar power supplies.
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Despite the fact that durable and reliable fluorescent lamps have firmly entered our lives, the improved ballast for them has not yet been appreciated by consumers. The main reason for this is the high price of electronic ballasts.
The main advantage of the ballast circuit for fluorescent lamps is to save the energy consumed by the light source (up to 20%) and increase its service life. By spending money on the purchase of electronic ballasts, we save on electricity and the purchase of new lamps in the future. The advantages also include noiselessness, soft start-up and ease of installation.
Using the instructions attached to the device, a compact electronic ballast chip can be easily installed in the lamp. By replacing the traditional choke, starter and capacitor with it, we will allow the lamp to become more economical.
Electronic ballast circuits for fluorescent lamps are as follows: 
On the electronic control board is:
As you know, the rectifier is not able to perfectly rectify the current. At the output of it, the ripple can be from 50 to 100 Hz, which adversely affects the operation of the lamp.
Before choosing an energy-saving light bulb, it is recommended to study the technical characteristics of its varieties, their advantages and disadvantages. Particular attention should be paid to the installation location of the compact fluorescent lamp. Very frequent switching on and off or frosty weather outside will significantly reduce the duration of the CFL.
Connecting LED strips to a 220 Volt network is carried out taking into account all the parameters of lighting devices - length, quantity, monochrome or multicolor. Read more about these features here.
The circuit for switching on a fluorescent lamp together with a ballast can be divided into four main phases.
The current frequency drops to the rated operating frequency. During operation, low voltage capacitors are constantly charged. Feedforward control is activated, which regulates the switching frequency of the half-bridge.
The power of the lamp is maintained in a fairly stable position, even if there are voltage fluctuations in the mains.
Conclusions:
A fluorescent lamp (LL) is a light source from a sealed glass bulb, inside which an electric electrode discharge is created, flowing in a gaseous medium. On its inner surface there is a phosphorus-containing layer (phosphor). Inside the lamp is an inert gas and 1% mercury vapor. When exposed to an electric discharge, they emit visually invisible ultraviolet light, which causes the phosphor to glow.
Ballasts for fluorescent lamps
If even one fluorescent lamp breaks in a room, mercury vapor will exceed the permissible values by 10 times. Its harmful effect persists for 1-2 months.
The electrically conductive gaseous medium inside fluorescent lamps has a negative resistance, which manifests itself in the fact that with increasing current, the voltage between the electrodes decreases.
Scheme of operation of a fluorescent lamp
Therefore, a current limiter LL1 is connected to the circuit - a ballast, as can be seen from the figure. The device also serves to create a short-term increased lamp ignition voltage, which is not enough in the current network. It is also called a choke.
The ballast also contains a small glow lamp E1 - starter. Inside it there are 2 electrodes, one of which is movable, it is made of a bimetallic plate.
In the initial state, the electrodes are open. When the mains voltage is applied to the circuit by closing the SA1 contact at the initial moment, no current passes through the fluorescent lamp, and a glow discharge is formed inside the starter between the electrodes. The electrodes heat up from it, and the bimetallic plate bends, closing the contact inside the starter. As a result, the current through the LL1 ballast increases and heats up the electrodes of the fluorescent lamp.
After the circuit, the discharge inside the starter E1 stops, and the electrodes begin to cool. In this case, they open, and as a result of self-induction, the inductor creates a significant voltage pulse that ignites the LL. At the same time, a current equal in magnitude to the nominal current begins to pass through it, which then decreases by 2 times due to the voltage drop across the inductor. This current is not enough to create a glow discharge in the starter, so its electrodes remain open while the fluorescent lamp is on. Capacitors C1 and C2 allow you to reduce reactive loads and increase efficiency.
The ballast limits the current flow. Part of the power heats up the device, which leads to energy losses. In terms of loss levels, the ballast for lamps can be as follows:
When the ballast is connected to the network, the alternating voltage leads the current in phase. Its designation always indicates the cosine of the angle of this lag, called the power factor. The smaller its value, the more reactive energy is consumed, which is an additional load. To increase the power factor to a value of 0.85, a capacitor with a capacitance of 3-5 microfarads is connected in parallel with the network.
Any electromagnetic choke creates noise. Depending on how much it can be reduced, ballasts are produced with normal (N), low (P), very low (C, A) noise levels.
The power of lamps and ballasts must be selected in accordance with each other (from 4 to 80 W), otherwise the lamp will fail prematurely. They are supplied in a kit, but you can choose your own.
The classic starting device from an electromagnetic ballast and a starter (EMPRA) has the following advantages:
In addition, it has a whole host of disadvantages:
The shortcomings of the chokes led to the need to create a new device. Electronic ballast is an innovative solution that improves the quality of LL operation and makes it durable. The electronic ballast circuit (electronic ballast) is a single electronic unit that forms the sequence of voltage changes for ignition.
Block diagram for starting lamps with electronic ballasts
The advantages of electronic circuits are as follows:
Externally, the electronic ballast looks as shown in the figure below.
Electronic ballasts for fluorescent lamps
The disadvantage of electronic ballasts is the high price due to the complexity of the circuit.
The electrodes of the lamp are heated, after which a high voltage is applied to them through the ballast. Its frequency is 20-60 kHz, which makes it possible to eliminate flicker and increase efficiency. Depending on the scheme, the launch can be instant or smooth - with an increase in brightness to the working one.
With a cold start, the service life of fluorescent lamps is significantly reduced.
An oscillatory circuit in the lamp power circuit is added to the process of heating the electrodes, which enters into electrical resonance before the discharge. In this case, the voltage increases significantly, the cathodes are heated more intensively, and as a result, ignition occurs easily. As soon as the discharge in the lamp begins, the oscillatory circuit immediately goes out of resonance and the operating voltage is established.
For cheap electronic ballasts or self-assembled ones, the principle of operation is similar to the choke option: the lamps are ignited with a high voltage, and the discharge is held with a small one.
Diagram of electronic ballast
As in all electronic ballast circuits, the voltage is rectified by diodes VD4-VD7, which is then filtered by capacitor C1. The filter capacitance is selected at the rate of 1 uF per 1 W of lamp power. With smaller capacitor values, the glow will be dimmer.
As soon as the connection to the network occurs, the capacitor C4 immediately begins to charge. When 30 V is reached, the dinistor CD1 breaks through and the transistor T2 opens with a voltage pulse, then a half-bridge self-oscillator of transistors T1, T2 and a transformer TR1 with two out-of-phase primary and one secondary windings starts to work. The resonant frequency of the series circuit of capacitors C2, C3, inductor L1 and the generator are close in magnitude (45-50 kHz). When the voltage on capacitor C3 rises to the start value, the lamp lights up. This reduces the generator frequency and voltage, and the inductor limits the current. Due to the high frequency, its dimensions are small.
Burnt parts in the circuit are often visible. How to check the electronic ballast? Most often, transistors fail. A burnt part can be detected visually. When doing do-it-yourself repairs, it is recommended to check the transistor paired with it and the resistors located nearby. Burnt ones are not always visible on them. A swollen capacitor must be replaced. If there are several burnt parts, the ballast is not repaired.
Sometimes after turning off the electronic ballast, the lamp continues to flicker weakly. One of the reasons may be the presence of potential at the input when zero is turned off. The circuit must be checked and connections made by oneself so that the switch is set to phase. It is possible that a charge remains on the filter capacitor. Then it should be connected in parallel to the resistance for discharging at 200-300 kOhm.
Due to power surges, it is often necessary to repair luminaires with electronic ballast. With an unstable power supply, it is better to use an electromagnetic choke.
A compact lamp (CFL) contains an electronic ballast built into the base. LL repair of low price and quality is carried out for the following reasons: burning of a filament, breakdown of transistors or a resonant capacitor. If the spiral burned out, do-it-yourself repairs will briefly extend the service life and it is better to replace the lamp. It is also not advisable to repair LLs in which the phosphor layer is burned (blackening of the bulb in the area of the electrodes). In this case, a serviceable ballast can be used as a spare.
Burning of the phosphor on a fluorescent lamp
Repair of the electronic ballast will not be required for a long time if you upgrade the CFL by installing an NTS thermistor (5-15 Ohm) in series with the resonant capacitor with your own hands. The part limits the starting current and protects the filaments for a long time. It is also advisable to make ventilation holes in the plinth.
Do-it-yourself ventilation device for heat removal from ballast
Holes are carefully drilled next to the tube for better cooling, as well as near the metal part of the base to remove heat from the ballast parts. Such repairs are possible only in dry rooms. In the middle, you can make a third row of holes with a larger diameter drill.
Repair with the installation of a thermistor is carried out with soldering the conductor on the bottom platform with solder. Then the convex part of the base is bent from the glass bulb and the second wire is released. After that, the base is removed and access to the printed circuit board is provided. After the repair is completed, the base is installed in the reverse order.
Tubular LLs with a length of 1200 mm are inexpensive and can illuminate large areas. The lamp can be made by hand, for example, from 2 lamps of 36 W each.
Homemade lamp
How to replace the electronic ballast in the lamp, this video will clearly tell.
LL should be fed with high frequency current, for which an electronic ballast is well suited. They contain little mercury vapor; here, heating of the filaments normalized in time and current is required to enter the operating mode.
Content:Lighting in large rooms is increasingly carried out using tubular fluorescent lamps. They are able to significantly save energy and illuminate the space with diffused light. However, their service life largely depends on the normal operation of all components. Among them, the ballast circuit of fluorescent lamps is of great importance, providing ignition and maintaining a normal operating mode.
Most conventional 50 Hz designs use electromagnetic ballasts for power supply. High voltage is obtained through the reactor when the bimetallic key opens. A current flows through it, providing heating of the electrodes with closed contacts.
These starting devices have a number of serious drawbacks that do not allow fluorescent lamps to fully use their resource when illuminating rooms. Flickering light, increased noise level, unstable light during power surges are created.
All these shortcomings are eliminated by the use of electronic ballasts (), called electronic ballast. The use of a ballast allows you to almost instantly light the lamp without noise and flicker. The high frequency range makes the lighting more comfortable and stable. The negative impact of mains voltage fluctuations is completely neutralized. All flashing and flashing faulty lamps are switched off by the control system.
All electronic ballasts are relatively expensive. However, in the future, there is a visible compensation of the initial costs. With the same quality of the luminous flux, energy consumption is reduced by an average of 20%. The light output of a fluorescent lamp is increased due to the higher frequency and increased efficiency of electronic ballasts compared to electromagnetic devices. The sparing mode of start-up and operation with the use of ballast allows you to increase the life of the lamps by 50%.
Operating costs are greatly reduced as no replacement of starters is required and the quantity is also reduced. When using a light control system, additional energy savings of up to 80% can be achieved.
The design of the electronic ballast uses an active power factor corrector, which ensures compatibility with the electrical network. The basis of the corrector is a powerful step-up pulse converter controlled by a special integrated circuit. This provides nominal operation with a power factor close to 0.98. The high value of this coefficient is maintained in any operating modes. Voltage change is allowed in the range of 220 volts + 15%. The corrector provides stable illumination even with significant voltage fluctuations in the network. An intermediate is used to stabilize it.
An important role is played by a network filter, which smooths out high-frequency ripples of the supply current. Together with the corrector, this device strictly regulates all components of the consumed current. The mains filter input is equipped with a protective unit with a varistor and a fuse. This allows you to effectively eliminate network surges. A thermistor is connected in series with the fuse, which has a negative temperature coefficient of resistance, which provides limiting of the input current surge, during the connection of the electronic ballast from the inverter to the network.
In addition to the main elements, the ballast circuit for fluorescent lamps requires a special protection unit. With its help, the condition of the lamps is monitored, as well as their shutdown in case of malfunction or absence. This device monitors the current that the inverter consumes and the voltage supplied to each of the lamps. If during a certain period of time the specified level of voltage or current exceeds the set value, then the protection is triggered. The same happens during a break in the load loop.
The actuating element of the protective unit is a thyristor. Its open state is maintained by the current passing through the 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 control unit of the electronic ballast is powered through the mains rectifier when the current passes through the ballast resistor. Reducing the power of the electronic ballast and improving its efficiency allows the use of a smoothing circuit current. This circuit is connected to the point where the inverter transistors are connected. Thus, the control system is powered. The construction of the circuit ensures the launch of the control system at the initial stage, after which, with a slight delay, the power circuit starts.
Models differ from each other in terms of rated voltage, resistance and overload. Modern devices are able to work in an economical mode. Ballasts are connected via controllers. As a rule, they are applied electrode type. Also, the connection diagram of the model involves the use of an adapter.
Electronic ballast circuits include a set of transceivers. The contacts of the models are of the switched type. A typical device consists of up to 25 pF. Regulators in devices can be used operational or conductor type. Stabilizers in ballasts are installed through the lining. To maintain the operating frequency, the device has a tetrode. The inductor in this case is attached through a rectifier.
Electronic ballast (circuit 2x36) of low efficiency is suitable for 20 W lamps. The standard scheme includes a set of expansion transceivers. Their threshold voltage is 200 V. The thyristor in devices of this type is used on the lining. The comparator fights overloads. Many models use a converter that operates at a frequency of 35 Hz. A tetrode is used to increase the voltage. Additionally, adapters are used to connect ballasts.
The electronic ballast (the connection diagram is shown below) has one transistor with an output to the plate. The threshold voltage of the element is 230 V. For overloads, a comparator is used, which operates at low frequencies. These devices are well suited for lamps up to 25 watts. Stabilizers are often used with variable transistors.
Many circuits use converters, and their operating frequency is 40 Hz. However, it can increase with increasing overloads. It is also worth noting that ballasts use dinistors to rectify the voltage. Regulators are often installed behind transceivers. Operating taxes issue a frequency of no more than 30 Hz.
Electronic ballast (2x36 circuit) for 15 W lamps is assembled with integrated transceivers. Thyristors in this case are mounted through a choke. It is also worth noting that there are modifications on open adapters. They are distinguished by high conductivity, but operate at low frequency. Capacitors are only used with comparators. during operation it reaches 200 V. Insulators are used only at the beginning of the circuit. Stabilizers are used with a variable regulator. The conductivity of the element is at least 5 microns.
The circuit diagram of the electronic ballast for 20 W lamps implies the use of an expansion transceiver. Transistors are commonly used in different capacities. At the beginning of the circuit, they are set to 3 pF. For many models, the conductivity index reaches 70 microns. In this case, the sensitivity coefficient is not significantly reduced. The capacitors in the circuit are used with an open regulator. The lowering of the operating frequency is carried out through a comparator. In this case, the rectification of the current occurs due to the operation of the converter.
If we consider circuits on phase transceivers, then there are four capacitors. Their capacitance starts at 40 pF. The operating frequency of the ballast is maintained at 50 Hz. Triodes for this are used on operational regulators. To reduce the sensitivity factor, various filters can be found. Rectifiers are quite often used on linings and are installed behind the throttle. The conductance of the ballast primarily depends on the threshold voltage. The type of regulator is also taken into account.
Electronic ballast (2x36 circuit) for 36 W lamps has an expansion transceiver. The device is connected via an adapter. If we talk about the performance of ballasts, then the rated voltage is 200 watts. Insulators for devices are suitable for low conductivity.
Also, the 36W electronic ballast circuit includes capacitors with a capacity of 4 pF. Thyristors are often installed behind filters. To control the operating frequency there are regulators. Many models use two rectifiers. The operating frequency for ballasts of this type is maximum 55 Hz. In this case, the overload can increase significantly.
The electronic ballast T8 (circuit shown below) has two low conductance transistors. The models use only contact thyristors. Capacitors at the beginning of the circuit are of high capacity. It is also worth noting that ballasts are produced on contactor stabilizers. Many models maintain a Heat Loss Coefficient of around 65%. The comparator is set with a frequency of 30 Hz and a conductivity of 4 microns. The triode for it is selected with a lining and an insulator. The device is switched on via an adapter.
The electronic ballast (2x36 circuit) with MJE13003A transistors includes only one converter, which is located behind the throttle. The models use a variable type contactor. The operating frequency of the ballasts is 40 Hz. In this case, the threshold voltage during overloads is 230 V. The triode is used in devices of the pole type. Many models have three rectifiers with a conductivity of 5 microns. The disadvantage of the device with transits MJE13003A can be considered high heat losses.
Ballasts with these transistors are valued for good conductivity. They have a low heat loss coefficient. The standard device circuit includes a wire converter. The throttle in this case is used with a lining. Many models have low conductivity, but the operating frequency is 30 Hz. Comparators for modifications are selected on a wave capacitor. Regulators are only suitable for operating type. In total, the device has two relays, and contactors are installed behind the throttle.
The ballast on the KT8170A1 transistor consists of two transceivers. The models have three filters for impulse noise. The rectifier is responsible for turning on the transceiver, which operates at a frequency of 45 Hz. Models use only variable-type converters. They operate at a threshold voltage of 200 V. These devices are excellent for 15 W lamps. Triodes in controllers are used as output type. The overload indicator may vary, and this is primarily due to the relay capacity. You also need to remember about the capacitance of the capacitors. If we consider wired models, then the above parameter for the elements should not exceed 70 pF.
Schematic diagram of the electronic ballast on transistors KT872A involves the use of only variable converters. The bandwidth is about 5 microns, but the operating frequency may vary. The transceiver for ballast is selected with an expander. Many models use several capacitors of different capacities. At the beginning of the chain, elements with plates are used. It is also worth noting that the triode is allowed to be installed in front of the inductor. Conductivity in this case will be 6 microns, and the operating frequency will not be higher than 20 Hz. At a voltage of 200 V, the overload at the ballast will be about 2 A. To solve problems with reduced sensitivity, stabilizers on expanders are used.
An electronic ballast (2x36 circuit) with single-pole dinistors is capable of operating at an overload of more than 4 A. The disadvantage of such devices is a high heat loss coefficient. The modification scheme includes two low conductivity transceivers. For models, the operating frequency is about 40 Hz. The conductors are attached behind the throttle, and the relay is installed only with a filter. It is also worth noting that the ballasts have a conductive transistor.
Capacitor is used low and high capacitance. At the beginning of the circuit, 4 pF elements are used. The resistance in this section is about 50 ohms. It is also necessary to pay attention to the fact that insulators are used only with filters. The threshold voltage for ballasts when turned on is approximately 230 V. Thus, the models can be used for lamps of different power.
Bipolar dinistors primarily provide high conductivity for the elements. Electronic ballast (2x36 circuit) is made with components on switches. In this case, the regulators are used operational type. The standard circuit of the device includes not only a thyristor, but also a set of capacitors. The transceiver is used in this case of a capacitive type, and it has a high conductivity. The operating frequency of the element is 55 Hz.
The main problem of devices is low sensitivity at high overloads. It is also worth noting that triodes can only operate at an increased frequency. Thus, the lamps often flash, and this is caused by overheating of the capacitors. To solve this problem, filters are installed on the ballasts. However, they are not always able to cope with overloads. In this case, it is worth considering the amplitude of the jumps in the network.
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 a breakdown of the gas, the appearance of a glow discharge and the appearance of an electric current in the circuit. The glow of the gas discharge is of a pale blue hue, 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. By changing the chemical composition of the phosphor, different colors of glow are obtained: various shades of white have been developed for fluorescent lamps (LDS), and lamps of a different color can be chosen for decorative lighting. The invention and mass production of fluorescent lamps is a step forward in comparison with low-efficiency incandescent lamps.
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 due to overheating, an additional load is switched on in series, limiting the amount of current, the so-called ballast. Sometimes the term choke is used to refer to it.
Two types of ballasts are used: electromagnetic and electronic. The electromagnetic ballast has a classic, transformer configuration: copper wire, metal plates. In electronic ballasts (electronic ballast) electronic components are used: diodes, dinistors, transistors, microcircuits.
For the initial ignition (start) of the discharge in the lamp in electromagnetic devices, an additional starting device is used - a starter. In the electronic version of the ballast, this function is implemented within a single electrical circuit. The device turns out to be light, compact and is united by a single term - an electronic ballast (electronic ballast). The mass use of electronic ballasts for fluorescent lamps is due to the following advantages:
Electronic ballast is an electronic board filled with electronic components. Schematic diagram of inclusion (Fig. 1) and one of the variants of the ballast scheme (Fig. 2) are shown in the figures.
Fluorescent lamp, C1 and C2 - capacitors 
Electronic ballasts may have different circuit solutions depending on the components used. The voltage is rectified by diodes VD4-VD7 and then filtered by capacitor C1. After the voltage is applied, the charging of the capacitor C4 begins. At a level of 30 V, the dinistor CD1 breaks through and the transistor T2 opens, then the oscillator on transistors T1, T2 and the transformer TR1 is turned on. The resonant frequency of the series circuit of capacitors C2, C3, 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 across capacitor C3 reaches the start value, the lamp lights up. This reduces the control frequency of the generator and voltage, and the inductor limits the current.
If it is not possible to quickly replace a failed electronic ballast, you can try to repair the ballast yourself. To do this, select the following sequence of actions to troubleshoot:
Relatively recently, fluorescent energy-saving lamps have become widely used in everyday life, adapted to standard cartridges for simple incandescent lamps - E27, E14, E40. In these devices, the electronic ballasts are inside the cartridge, so repairing these electronic ballasts is theoretically possible, but in practice it is easier to buy a new lamp.
The photo shows an example of such an OSRAM lamp with a power 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 virtually unchanged.
T8 lamps have a glass bulb diameter of 26 mm. The commonly used T10 and T12 lamps have diameters of 31.7 and 38 mm respectively. For lamps, LDS with a power of 18 watts is usually used. T8 lamps do not lose performance during power surges, but if the voltage drops by more than 10%, lamp ignition is not guaranteed. The ambient temperature also affects the reliability of the LDS T8. At sub-zero temperatures, the luminous flux decreases, and failures in the ignition of the lamps may occur. T8 lamps have a life span of 9,000 to 12,000 hours.
You can make a simple lamp from two lamps as follows:
