Connection diagram for a two-lamp fluorescent lamp. Do-it-yourself radio circuits for the home. How the housekeeper works

D To maintain and stabilize the discharge process, a ballast resistance is switched on in series with the fluorescent lamp in the AC network in the form of or choke and capacitor. These devices are called ballasts (ballasts).

The mains voltage at which the fluorescent lamp operates in steady state is not sufficient to ignite it. To form a gas discharge, i.e., breakdown of the gas space, it is necessary to increase the emission of electrons by preheating them or applying an increased voltage pulse to the electrodes. Both are provided by a starter connected in parallel with the lamp.

Let's consider How does the process of igniting a fluorescent lamp occur?

The starter is a miniature glow discharge lamp with neon filling, having two bimetallic electrodes, which are open in the normal position.

When voltage is applied, a discharge occurs in the starter and the bimetallic electrodes, bending, become short-circuited. After their closure, the current in the circuit of the starter and electrodes, limited only by the resistance of the choke, increases to two to three times the operating current of the lamp and the electrodes of the fluorescent lamp quickly heat up. At the same time, the bimetallic electrodes of the starter, cooling down, open its circuit.

When the circuit is broken by the starter, an increased voltage pulse occurs in the throttle, as a result of which a discharge occurs in the gaseous environment of the fluorescent lamp and its ignition occurs. After the lamp is lit, the voltage on it is about half the mains voltage. This voltage will also be present at the starter, but this is not enough to close it again. Therefore, when the lamp is on, the starter is open and does not participate in the operation of the circuit.

Single-lamp starter circuit for switching on a fluorescent lamp: L - fluorescent lamp, D - choke, St - starter, C1 - C3 - capacitors.

A capacitor connected in parallel with the starter and capacitors at the input of the circuit are designed to reduce the level of radio interference. A capacitor connected in parallel with the starter, in addition, helps to increase the service life of the starter and affects the lamp ignition process, helping to significantly reduce the voltage pulse in the starter (from 8000 -12,000 V to 600 - 1500 V) while simultaneously increasing the pulse energy (by increasing its duration).

The disadvantage of the described starter circuit is the low cos phi, not exceeding 0.5. An increase in cos phi is achieved either by turning on a capacitor at the input or by using an inductive-capacitive circuit. However, in this case, cos phi 0.9 - 0.92 as a result of the presence of higher harmonic components in the current curve, determined by the specifics of the gas discharge and the control gear.

In two-lamp luminaires, reactive power compensation is achieved by turning on one lamp with an inductive ballast and the other with an inductive-capacitive ballast. In this case cos phi = 0.95. In addition, such a ballast circuit makes it possible to smooth out pulsations to a significant extent. luminous flux fluorescent lamps.

Switching diagram for fluorescent lamps with split-phase ballasts

The most widely used for switching on fluorescent lamps with a power of 40 and 80 W is the two-lamp pulse starter ignition circuit using ballast compensated devices 2UBK-40/220 and 2UBK-80/220, operating according to the “split phase” scheme. They are complete electrical devices with chokes, capacitors and discharge resistors.

Only the inductive reactance is connected in series with one of the lamps, which creates a phase lag of the current from the applied voltage. In series with the second lamp, in addition to the inductor, a capacitor is switched on, the capacitive reactance of which is approximately 2 times greater than the inductive reactance of the inductor, creating a current advance, as a result of which the total power factor of the set is about 0.9 -0.95.

In addition, connecting a specially selected capacitor in series with the inductor of one of the two lamps provides such a phase shift between the currents of the first and second lamps, at which the depth of oscillations of the total luminous flux of the two lamps will be significantly reduced.

To increase the electrode heating current, a compensating coil is switched on in series with the capacitor, which is turned off by the starter.

Wiring diagram for switching on a two-lamp starter apparatus 2UBK: L - fluorescent lamp, St - starter, C - capacitor, r - discharge resistance. The 2UBK ballast housing is shown with a dotted line.

Starterless circuits for switching on fluorescent lamps

The disadvantages of starter switching circuits (considerable noise created by ballasts during operation, flammability in emergency modes, etc.), as well as the low quality of manufactured starters, have led to a persistent search for starterless, economically feasible, rational ballasts in order to primarily use them in installations where quite simple and cheap.

For reliable operation of starterless circuits, it is recommended to use lamps with a conductive strip applied to the bulbs.

The most widespread transformer circuits for quick start-up of fluorescent lamps in which as ballast resistance a choke is used, and preheating of the cathodes is carried out by a filament transformer or.

Currently, calculations have established that starter circuits for interior lighting are more economical, and therefore they are predominantly widespread. In starter circuits, energy losses are approximately 20 - 25%, in starterless circuits - 35%

Recently, circuits for switching on fluorescent lamps with electromagnetic ballasts are gradually being replaced by circuits with more functional and economical electronic ballasts (EPGs).

When calculating lighting networks with fluorescent lamps, it is necessary to take into account that even with compensated circuits without ballasts, the phase shift cannot be completely eliminated. Therefore, when determining the design current of networks with fluorescent lamps, it is necessary to take cosine phi = 0.9 for circuits with reactive power compensation, and when there are no capacitors in circuits, cosine phi = 0.5. In addition, it is necessary to take into account power losses in the ballasts.

When choosing wire cross-sections for four-wire networks with fluorescent lamps, you should take into account some features of such networks. The fact is that the nonlinearity of the current-voltage characteristic of fluorescent lamps, as well as the presence of an inductor with a steel core and capacitors in their target, result in a non-sinusoidal current curve and, as a result, the appearance of higher harmonics, which significantly change the current of the neutral wire even with a uniform phase load.

The current in the neutral wire can reach values ​​close to the current in the phase wire, 85-87% of I f. This implies the need to choose the cross-section of the neutral wire in four-wire fluorescent lighting networks equal to the cross-section of the phase wires, and when laying wires in pipes, the permissible current load must be taken as for four wires in one pipe.

Despite the emergence of more “advanced” LED lamps, daylight fixtures continue to be in demand thanks to affordable price. But there's a catch: you can't just plug them in and light them without adding a couple of extra elements. Electrical diagram Connecting fluorescent lamps, which includes these parts, is quite simple and serves to start lamps of this type. You can easily assemble it yourself after reading our material.

Design and operating features of the lamp

The question arises: why do you need to assemble some kind of circuit to turn on such light bulbs? To answer it, it is worth analyzing their operating principle. So, fluorescent (otherwise - gas-discharge) lamps consist of the following elements:

1. A glass flask whose walls are coated on the inside with a phosphorus-based substance. This layer emits a uniform white glow when hit with ultraviolet radiation and is called a phosphor.
2. On the sides of the flask there are sealed end caps with two electrodes each. Inside, the contacts are connected by a tungsten filament coated with a special protective paste.
3. The daylight source is filled with an inert gas mixed with mercury vapor.

Reference. Glass flasks can be straight or curved in the shape of a Latin “U”. The bend is made in order to group the connected contacts on one side and thus achieve greater compactness (for example, widely used light bulbs - housekeepers).

The glow of the phosphor is caused by a flow of electrons passing through mercury vapor in an argon environment. But first, a stable glow discharge must arise between the two filaments. This requires a short-term high voltage pulse (up to 600 V). To create it when the lamp is turned on, the above-mentioned parts are needed, connected according to a certain scheme. The technical name of the device is ballast or ballast.

In housekeepers, the ballast is already built into the base

Traditional circuit with electromagnetic ballast

In this case, the key role is played by a coil with a core - a choke, which, thanks to the phenomenon of self-induction, is capable of providing a pulse of the required magnitude to create a glow discharge in a fluorescent lamp. How to connect it to power via a choke is shown in the diagram:

The second element of the ballast is the starter, which is a cylindrical box with a capacitor and a small neon light bulb inside. The latter is equipped with a bimetallic strip and acts as a circuit breaker. Connection via electromagnetic ballast works according to the following algorithm:

1. After the main switch contacts close, the current passes through the inductor, the first filament of the lamp and the starter, and returns through the second tungsten filament.
2. The bimetallic plate in the starter heats up and closes the circuit directly. The current increases, causing the tungsten filaments to heat up.
3. After cooling, the plate returns to its original shape and opens the contacts again. At this moment, a high voltage pulse is generated in the inductor, causing a discharge in the lamp. Then, to maintain the glow, 220 V coming from the mains is enough.

This is what the starter filling looks like - only 2 parts

Reference. The principle of connection with a choke and a capacitor is similar to a car ignition system, where a powerful spark on the candles jumps when the high-voltage coil circuit breaks.

A capacitor installed in the starter and connected in parallel to the bimetallic breaker performs 2 functions: it prolongs the action of the high-voltage pulse and serves as protection against radio interference. If you need to connect 2 fluorescent lamps, then one coil will be enough, but you will need two starters, as shown in the diagram.

More details about the operation of gas-discharge light bulbs with ballasts are described in the video:

Electronic activation system

Electromagnetic ballast is gradually being replaced by new electronic system Electronic ballasts devoid of such disadvantages:

• long lamp startup (up to 3 seconds);
• crackling or clicking noises when turned on;
• unstable operation at air temperatures below +10 °C;
• low-frequency flickering, which has a detrimental effect on human vision (the so-called strobe effect).

Reference. The installation of daylight sources is prohibited on production equipment with rotating parts precisely because of the strobe effect. With such lighting, an optical illusion occurs: it seems to the worker that the machine spindle is motionless, but in fact it is spinning. Hence - industrial accidents.

The electronic ballast is a single block with contacts for connecting wires. Inside there is an electronic frequency converter board with a transformer, replacing the outdated electromagnetic type control gear. Connection diagrams for fluorescent lamps with electronic ballast are usually depicted on the unit body. Everything is simple here: on the terminals there are indications where to connect the phase, neutral and ground, as well as the wires from the lamp.

Starting light bulbs without a starter

This item electromagnetic ballast It breaks down quite often, and there is not always a new one in stock. To continue to use the daylight source, you can replace the starter with a manual breaker - a button, as shown in the diagram:

The point is to manually simulate the operation of a bimetallic plate: first close the circuit, wait 3 seconds until the lamp filaments warm up, and then open it. Here it is important to choose the right button for 220 V voltage so that you do not get an electric shock (suitable for a regular doorbell).

During the operation of a fluorescent lamp, the coating of the tungsten filaments gradually crumbles, which is why they can burn. The phenomenon is characterized by blackening of the edge zones near the electrodes and indicates that the lamp will soon fail. But even with burnt-out spirals, the product remains operational, it just needs to be connected to the electrical network according to the following diagram:

If desired, a gas-discharge light source can be ignited without chokes and capacitors, using a ready-made mini-board from a burnt energy saving light bulbs, which works on the same principle. How to do this is shown in the following video.

The so-called “daylight” lamps (LDL) are certainly more economical than conventional incandescent lamps, and they are also much more durable. But, unfortunately, they have the same “Achilles heel” - the filament. It is the heating coils that most often fail during operation - they simply burn out. And the lamp has to be thrown away, inevitably polluting environment harmful mercury. But not everyone knows that such lamps are still quite suitable for further work.

In order for the LDS, in which only one filament has burned out, to continue to work, it is enough to simply bridge those pin terminals of the lamp that are connected to the burnt-out filament. It is easy to determine which thread is burnt out and which is intact using an ordinary ohmmeter or tester: a burnt-out thread will show an infinitely high resistance on the ohmmeter, but if the thread is intact, the resistance will be close to zero. In order not to bother with soldering, several layers of foil paper (from a tea wrapper, milk bag or cigarette package) are strung onto the pins coming from the burnt-out thread, and then the entire “layer cake” is carefully trimmed with scissors to the diameter of the lamp base. Then the LDS connection diagram will be as shown in Fig. 1. Here, the EL1 fluorescent lamp has only one (left according to the diagram) whole filament, while the second (right) is short-circuited with our improvised jumper. Other elements of the fluorescent lamp fittings - such as inductor L1, neon starter EK1 (with bimetallic contacts), as well as interference suppression capacitor SZ (with a rated voltage of at least 400 V) may remain the same. True, the ignition time of the LDS with such a modified scheme can increase to 2...3 seconds.

A simple circuit for switching on an LDS with one burnt-out filament

Connection diagram for LDS with additional electrodes

A simple circuit for switching on an LDS with two burnt-out filaments using a voltage quadrupler

The glow of fluorescent lamps, related to gas-discharge lamps, is UV radiation resulting from the action of an electric discharge on mercury vapor in the bulb.

This radiation is invisible to the human eye; what makes it visible is a layer of phosphor applied to inner surface flasks.

To create an electrical discharge in a fluorescent lamp, which has a fairly high resistance, a high voltage pulse is correspondingly required, after which a resistance must be included in the power circuit to prevent it from burning out to limit the current.

To accomplish this task, special ballast equipment (ballast) or so-called ballast is used.

Currently, there are two types of ballasts: electronic ballast - electronic ballast and electronic ballast - electromagnetic ballast. Each of them, of course, has its own advantages and disadvantages in use. This article provides detailed description and connection diagrams for fluorescent lamps using EMC.

Connection diagrams for fluorescent lamps

In addition to the fluorescent lamp itself (L), the circuit contains a switch, a choke (Dr) and a starter (St). A choke is a device that provides a high-voltage pulse for ignition and limiting its current (power loss - in fact, it is ballast), in order to avoid burnout of the spirals.

The starter is structurally a gas-discharge lamp with one or two movable contacts, the bulb of which contains an inert gas, most often neon. The operating voltage of the starter is always lower than the mains voltage, but exceeds the voltage of the fluorescent lamp.

Description of the circuit operation. When voltage is applied to the lamp coils through a choke connected in series with it, it is supplied to the contacts of a parallel-connected starter. As a result of the occurrence of a glow discharge between the electrodes, the latter short-circuit due to their bending.

By closing the starter contacts, as can be seen from the diagram, the voltage at the lamp contacts increases, ensuring the heating of its mercury vapor and coils. By analogy, their opening occurs: cooling of the contacts leads to extension.

This opening causes a high voltage surge in the inductor - a pulse sufficient to ignite the lamp. Thus, switching occurs, and the voltage applied to the starter will be insufficient to cause a discharge in it and short circuit the electrodes.

The dotted line highlights the connection of capacitor C. It is not a mandatory element of the circuits and is designed to reduce the level of radio interference caused by the closure of the starter contacts at the moment of switching on.