Lighting plays an important role in human life. It is basic, accent, decorative. Various light sources are used to create the backlight. The most modern, reliable and high-quality devices are LED lamps. They have many advantages over classic light sources. However, the design of an LED light bulb is more complicated.
Principle of operation
The basis of the LED is a semiconductor crystal, consisting of two materials of different conductivity.
The principle of operation of an LED lamp is as follows: when an electric current is applied, particles transfer from one semiconductor to another, accompanied by the creation of a light particle - a photon. Both semiconductors can only transmit current in one direction, so it is important to observe the polarity when connecting. During the supply of current, other processes occur. Part of the energy is spent on heat.
LEDs are made of different materials, so their spectrum, flow intensity, brightness also differ. Currently, light emitting diodes cover almost the entire range of radiation.
LEDs are used in a variety of areas: to create lighting in the house, at work, in administrative buildings. With their help, advertising, artistic and architectural lighting is done. LEDs can be found in streetlights.
LED lamp benefits
Modern light sources must be economical, efficient and safe. LEDs are fully suitable for these characteristics. A light emitting diode requires a small amount of energy to operate, while they give out bright lighting with minimal heat. LED light sources have a reduced sensitivity to surges in the network and have a large number of on and off cycles. When voltage is applied, they light up immediately, it does not take time to warm up. LEDs for lighting lamps compare favorably with other light sources for their long life - up to 50,000 hours.
The safety of LEDs lies in the absence of harmful components. There are no mercury vapors and a mixture of inert gases in the flask; therefore, they do not require special disposal conditions. LEDs are also made in a durable high-quality housing. The devices have a low ripple coefficient, so they are safe for human health.
On sale you can find a wide range of LED lamps. They differ in their characteristics, sizes, color temperature, design features. LED lamps are made in various forms - a candle, a cylinder, a tube and others.
The disadvantage that limits the widespread use of LED devices is their high cost.
LED source device
The overall design of the lamps is identical, there may be slight differences. They are more complicated from a technical point of view than incandescent lamps. To find out what a light bulb consists of, you need to disassemble it, while in a classic light source with a filament, you can view the inside through a glass flask.
What the LED lamp consists of:
- Led. One or more LEDs are installed in the lamp. They differ in power, light color, size. The number of diodes in the matrix can be different, calculated at the factory to ensure the optimal level of light.Diodes are soldered to an aluminum or textolite board of various sizes and shapes. Groups are connected to each other in series.
- Driver. It is used to convert the mains voltage to the required value for the LEDs. Driver schemes are different, most often used transformer. The design distinguishes open and closed, which are installed directly in the lamp housing. Low-cost Chinese products often include low-quality drivers that are ineffective and can be harmful.
- Basement LED bulbs came to replace incandescent lamps, so they should be installed in the same way. Devices with standard socles E27 and E14 are manufactured.
- Body. The flask is made of plastic or glass. Full tightness is not required, as there are no harmful mercury vapors and gases in the composition.
- Radiator. Since some heat is generated during operation, it must be removed so that there is no overheating. An aluminum board reduces the negative effects of temperature, but this may not be enough. Therefore, expensive high-quality bulbs are additionally equipped with radiators.
The assortment of products with E14 and E27 cap can be divided into three categories - brand, low-quality and filament.
Branded products
The device of the LED lamp manufactured by a well-known company must include:
- Hemispherical diffuser. It can be made of plastic or glass.
- Aluminum printed circuit board with heat transfer paste.
- A set of chips.
- Driver. It consists of a pulse transformer, microcircuits, polar capacitors, planar elements. It is also a base / radiator connector.
- Base of polyethylene terephthalate.
- Base with thread of the required diameter, made of nickel-plated brass.
In a quality device, there is always a radiator. It is voluminous and stained with white polymer. It increases the weight and dimensions of the light bulb, but is an indispensable element for stable operation.
Low quality products
Instruments of unknown manufacture usually have a low cost. This is due to the use of low-quality materials and the lack of important details - a radiator and a driver. Instead of the driver, a conventional power supply is used, located next to the LEDs. The role of the radiator is performed by the housing in which the holes are made. This method is ineffective, so cheap bulbs quickly fail.
The board is attached to the case using a special latch. The base and the board are connected by soldering. Such a connection cannot provide high reliability and continuous operation of LEDs.
Filament devices
Outwardly, the filament bulb is similar to an incandescent lamp. Its important distinguishing feature is that additional heat removal is not required. This LED light bulb consists of a filament and a bulb.
It works on the basis of LED threads. Their number is selected depending on the lamp power. LEDs are placed on a thin glass rod - this design is called filament. The phosphor is applied along the entire length, so the lamp is yellow. Heat is removed through a flask, inside which is a mixture of gases.
The disadvantages of a filament lamp include a high ripple ratio. Frequent blinking negatively affects the vision and psyche of a person, so work is underway to modernize the lamp design. A high-quality driver must be installed in a plastic insert in the form of a ring between the bulb and the base.
Assembly methods
LED lamps can be divided into several categories according to the method of assembly:
- Dip (dual inline package). This is the oldest and simplest design. It is an LED located in a protective cylindrical housing with two or more leads.They shine brightly, differ in a wide range of colors and low heat. There are one-color and multi-color.
Piranha LEDs - Piranha. These devices have a high luminous flux. Rectangular with 4 pins. Compared to previous ones, piranha is firmly mounted on the board. It has a lead substrate, which increases thermal conductivity. It works in a wide temperature range.
- SMD These are LEDs with a power of 0.01 - 0.2 W, characterized by the presence of several crystals on one ceramic substrate. The case is covered with a phosphor. The disadvantages include the impossibility of repair. If at least one LED in the group breaks, you will have to replace the entire board.
- COB. One of the most reliable diode manufacturing technologies. The semiconductor crystal is mounted on a board without a housing and substrate and is coated with a phosphor. They are distinguished by high power and small glow area.
The most common technology is COB.
Recommendations for checking the lamp when buying
When buying a lighting product, it should be visually inspected in a store. The case must be free of scratches and dents. Make sure you have a radiator. It can be monolithic or type-setting. Dimensions depend on the power of the lamp - the higher it is, the larger the radiator.
The base is also checked. It should be free of mechanical defects and backlash. If possible, check the lamp operation by connecting it to the mains. You need to look at the light through the phone’s camera to make sure there are no ripples. If blinking is noticeable, the lamp is of poor quality, it is not recommended to buy it.
Before making a choice, it is worthwhile to carefully study the technical specifications: how many volts the LEDs are in the lamp, color temperature, ripple factor.
