Electronic ballast for a fluorescent lamp. Principle of operation of fluorescent lamps

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

The standard model includes a transformer, dinistor and transistor. Quite often a fuse is installed to protect the system. Special lamps are provided for connecting the lamps. Also in the device there are outputs to which electricity is supplied.

Principle of operation

The principle of operation of electronic ballast is based on current conversion. The whole process begins after the supply of electricity to the channel. Then the throttle enters the work. At this stage, the limiting frequency of the device is significantly reduced. In this case, the negative resistance in the circuit, on the contrary, increases. Then the current passes through the dinistor and hits the transistor. As a result, the current is converted. Eventually, the voltage of the desired range for the fluorescent lamp passes through the transformer .

Models of diode type

Models of diode type are considered to be budgetary. In this case, the transformers are used only as a down-type. Some manufacturers install an open type of transistors. Due to this, the process of frequency reduction in the circuit does not occur very sharply. Two condensers are used to stabilize the output voltage. If we consider modern ballast models, then there are operating-type dinistors. Previously, they were replaced by conventional converters.

Two-contact models

This type of electronic ballast for a fluorescent lamp 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 devices of the most diverse. If we consider common models, then there are lowering analogs. However, single-phase configurations are not inferior to them in terms of parameters.

There are two capacitors in the chain in all. Also two-contact electronic ballast schemes of energy-saving lamps include a choke that is installed behind the output channels. Transistors for models are only capacitive. In the market they are presented both permanent and variable type. Fuses in devices are rarely used. However, if a thyristor is installed in the circuit to rectify the current, then one can not do without it.

Scheme of ballast "Epra" 18 W

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

Ballast "Epra" 2x18W

The specified electronic ballast 2х18 (the scheme is shown below) consists of output transistors, and also a step-down transformer. If we talk about a transistor, then in this case it is provided for an open type. There are two capacitors in the circuit. Another electronic ballast "Epra" 18 W has a choke, which is located under the transformer.

Condensers are installed as standard on 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 qualitative dynistor. There are two channels in total for the model.

Scheme of ballast "Epra" 4х18 W

This electronic ballast 4х18 (the circuit is shown below) includes capacitors of inverting type. Their capacity is exactly 5 pF. In this case, the parameter of negative resistance in electronic ballasts is up to 40 Ohm. It is also important to mention that the throttle in the presented configuration is located under the dynistor. The transistor of this model has one. The transformer for rectifying the current is applied in a down-type. Overload it is able to withstand the network large. However, the fuse in the circuit is still installed.

Ballast Navigator

The electronic ballast Navigator (the circuit is shown below) includes a unijunction transistor. Also, the difference of this model lies in the availability of a special regulator. With its help, the user can adjust the output voltage parameter. If we talk about the transformer, then it is in the chain provided for a down-type. It is located near the throttle and is fixed on the plate. Resistor for this model is selected capacitive type.

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

Electronic ballast circuit on transistors EN13003A

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

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

Use of step-down transformers

The electronic ballast for a fluorescent lamp with step-down transformers often includes voltage regulators. In this case, transistors are used, as a rule, of an open type. They are valued by many specialists for the high conductivity of the current. However, for high-quality operation of the device, a qualitative dynistor is very important.

Operational analogs are often used for step-down transformers. 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 fearful for them.

Application of vector transistors

Vector transistors in electronic ballasts are very rarely used. However, in modern models they still meet. If we talk about the characteristics of the components, it is important to note that they keep negative resistance at 40 ohms. However, with overloads, they cope quite badly. In this case, an important role is played by the output voltage parameter.

If we talk about transistors, then for these transformers they are more than 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 in compactness significantly lose to competitors with lowering configurations.

Scheme with integrated controller

Electronic ballast for fluorescent lamps with integrated controller is quite simple. In this case, the transformers are of the lower type. There are two capacitors in the system. To reduce the limiting frequency, the model has a dinistor. The transistor is used in electronic ballast of operating type. Negative resistance, it is able to withstand at least 40 ohms. Output triodes in models of this type are almost never used. However, the fuses are installed, and when the network fails, they help greatly.

Application of low-frequency triggers

The electronic ballast for fluorescent lamps is installed when the negative resistance in the circuit exceeds 60 ohms. The load from the transformer is very good. Fuses are installed very rarely. Transformers for models of this type are only used in vector form. 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. Compact electronic ballasts are quite different. In this case, much depends on the components of the device used. If we talk about models with regulators, then they require a lot of space. Also they are able to work in electronic ballasts on only two capacitors.

Models without regulators are very compact, but transistors for them can only be used in an orthogonal type. They differ in good conductivity. However, it should be borne in mind that these electronic ballasts in the market to the buyer will not be expensive.