Transformers for halogen lamps
The electrical equipment in our house, including lighting, works on electricity, with a voltage of 220V.But the usual incandescent bulb with a tungsten filament is yesterday. The efficiency is low, the durability is low, and the frequency of 50 Hz creates an additional burden on the eyesight. The output is to use a transformer for halogen lamps and use it to use high-frequency halogen lamps powered by low-voltage electricity.
Transformer for halogen lamps reduces voltage from 220V to 12V.Halogen lamps shine from electricity with a voltage of 12V.
Transformers are divided into two types:
- winding( induction);
- electronic.
Winding and electronic transformers
The first kind of devices - the winding transformer for halogen lamps is two copper windings that interact by means of an electromagnetic field.
An electronic transformer for halogen lamps converts electricity using numerous special devices.
Today, the electronic transformer for halogen lamps in front of the winding induction has its advantages:
- is lightweight and compact with small dimensions;
- is well protected: it has a high degree of protection against short circuits;
- is almost noiseless: it has a low noise level;
- stable in operation without load( idling mode);The
- is equipped with overload protection and protection against overheating;
- allows for a soft start;
These features ensure the durability of the work, extend the life of both the transformer and halogen lamps.
Selection of transformers
Calculation and selection of step-down transformers are carried out according to two main criteria:
- By output voltage.
- At rated power.
The first parameter shows which halogen lamps of which voltage can be connected using a transformer. The second gives the total power of the connected lamps connected with it. The value of the main parameters is displayed on the cover of the transformer housing.
If you need to connect a large number of halogen lamps, they should be divided into groups. To do this, you can use the following arguments:
- Connecting without splitting into groups requires a more powerful and correspondingly larger transformer. Therefore, there may not be enough room when installing it.
- If one transformer fails, only part of the lighting will go out.
- More powerful transformers are much more expensive.
- The operation of halogen lamps without loss of power requires the use of wires no longer than 3 m.
Dividing the lighting into groups, we will ensure this condition.
Schemes of transformers
This transformer is widely used in household lighting, for example table lamps with halogen lighting.
The widely used transformer( Figure 2) includes a bi-directional diode "TRIGGER DIODE" and works as follows: the diode bridge rectifies the alternating voltage to half-sine wave with a doubled frequency. Bi-directional D6 transistor triggers transformer transformer and half-bridge generation, which allows to bring the frequency of the electric current at the output to 30-50 kHz.
More advanced transformers with IR2161 chip are being used now. The use of the chip, having only 8 contacts, significantly significantly increased the reliability of the transformers of the devices, primarily due to the reduction in the number of constituent components. It is also highly technological, namely:
- load protection against short-circuit;
- protection against overcurrent( both protects have an automatic restart);
- intelligent half bridge driver;
- by sweeping the operating frequency, which reduces electromagnetic interference;
- powerful launch at 150 μA;
- possibility to use with phase dimmers;
- compensated output voltage shift, which extends lamp life;
- "soft start" start, which allows you to exclude the lamps from current overload.
Transformers for halogen lamps and transformers for LEDs: are they interchangeable?
The transformer for halogen lamps has its "relative" - a transformer for LED lighting. But even with the same rated power and output voltage, these transformers are not interchangeable.
The fact is that in a halogen lamp the light source is a filament. In the light of the LED there is a completely different physics. The electric current passes through the P / N junction of the diode and gives off some of the energy in the form of a photon of light. This difference in the physical phenomenon of the glow of a halogen lamp and LED puts different requirements on transformers. Without going into the deep analysis of oscillograms of transformers within the framework of this article, we will make entries:
- 12V at the output of the electronic transformer is the average voltage. In reality there are short-term jumps up to 40V.The halogen lamp "swallows" this jump without damage, and for a light-emitting diode it can be fatal.
- In addition to short-term voltage surges, electronic halogen transformers are characterized by an unstable output voltage. It can be in the range of 11-16V and depends on the voltage of the network at the input, the connected power, the temperature of the medium.
- The halogen transformer produces a non-rectified voltage. There are both positive and negative impulses in it. For long-term operation of the LED, rectified voltage is required, the pulse amplitude plot is close to a straight line.
LED lamps have a power 10 times smaller than the power of halogen lamps. But an electronic transformer for halogen lamps can not work at low loads. When the load is less than 30 watts, it can turn on and off one by one, or it will not turn on at all.
Further use of halogen lamps in public places and everyday life is very promising primarily due to electrical safety. In addition, the use of this method of lighting can significantly reduce power consumption.