The widespread use of LEDs begins in the mid-60s of the last century. Since then, this device has undergone many changes. And today, when LEDs have fallen significantly in price, their popularity among consumers has grown significantly. Lighting realized through the use of LEDs is ten steps ahead of incandescent lamps and fluorescent lighting devices - they are many times more economical, reliable and durable.
What is an LED and how does it work
An LED is a device that uses the properties of a p-n junction and emits photons, converts electric current into light radiation, which occurs when the reverse combination of electrons and holes in the region of the p-n junction. That is, a necessary condition for connecting LEDs to produce a glow is a p-n junction, which is the contact of two semiconductors with different types of conductivity. For these purposessemiconductor crystals are treated with acceptor impurities on the one hand, and donor impurities on the other. In this case, for the emission of light, the proximity of the energy of light quanta in the visible range with the band gap of the active region of the LED is necessary. In addition, the crystal must contain a negligibly small number of defects, due to which the reverse combination of electrons and holes in the region of the p-n junction occurs without radiation.
How to connect?
Connection of LEDs is subject to strict observance of polarity. For these purposes, the outputs of the LEDs have the appropriate names: anode and cathode. Accordingly - plus and minus.
The LED is capable of emitting a glow only when directly turned on. When you turn it back on, it permanently fails.
Since the LED can only emit light at certain voltage and current values, a limiting resistance must be introduced into the wiring diagram.
How to connect an LED to 220V?
How is it possible to do this? Connecting an LED to a 220 V current source is not at all as easy as it might seem. The essence of the problem lies in the technical characteristics of the device, whose operation is based on the principle of passing current through the crystals, as a result of which they begin to produce a glow. To comply with this principle, another device is needed - a driver, whose job is to control the supply of current to the crystal. At the same time, the driver limits it to the amount required for specific models of LEDs used.
Otherwisethe connection of the LEDs is carried out directly to a voltage of 220 V and is used when the LED should look like a low-power indicator and when only one or a few elements are involved in the connection. In most cases, the LED is used as a light source and is connected through a driver that already has all the necessary parameters for the normal operation of the device.
The LED will not glow if the voltage applied to it is less than the required value. On the other hand, if such a voltage exceeds the desired value, the device will fail. To avoid such cases, a current-limiting resistor is used to connect the LED.
An approximate driver connection diagram for decorative LED lighting is shown below.
The main feature of the driver is the conversion of alternating current flowing in a conventional household outlet, and as a result, a constant current is supplied to the LED.
Serial connection of LEDs
The connection of such devices has its own characteristics. Connecting several LEDs at once is best done in series. This connection will reduce energy consumption and allow you to connect a large number at the same time. But at the same time, all series-connected LEDs must be of the same type, and the power supply must have sufficient power and be able to provide the necessary voltage.
Connecting LEDs according to this principle is quite simple. Diodes are connected in series. A striking example of such a connection is an ordinary Christmas tree garland.
Arduino LED connection
How to solve the problem so that the LED turns on and off with an interval of 1 second? The so-called sketch can help us with this - a program created in the Arduino environment. Arduino is an electronic designer and a convenient platform that has become the most widely used among electronics enthusiasts, since this system is quite simple and easy to use. Arduino-based devices can control various actuators. In particular, the LED.
The figure below shows the connection diagram of the LED to the Arduino controller, on which the device is connected to the eighth pin. This fact must be taken into account when programming, setting the necessary parameters.
Parallel connection
Parallel connection of LEDs is widely used by the population in everyday life - in any LED display or LED matrix.
LEDs have technological discrepancies in the value of direct voltage reduction. Accordingly, different currents will pass through them. In this case, the light intensity will also vary, which the human eye perceives as different brightness. For this reason, the currents must be equalized with ballast resistors.
The figure shows the parallel connection diagramLEDs in one way. At the same time, option "a" is erroneous, it is not recommended to apply it in practice. The correct option "b" is with ballast resistors.
Self connection
Do-it-yourself LED connection must be carried out in accordance with all the rules. For connection, it is necessary to use small wires due to the fact that the resistance of such a wire will be almost equal to the resistance of the LEDs. In this case, experience shows that the voltage drops depending on the length of the wire. For this reason, power supplies are located near LED devices. Or they use power supplies for LEDs with an output voltage of 24 V, 36 V or 48 V. In turn, manufacturers of LED strips produce them for different voltages:
Connection to 1.5 V. With this connection, LEDs whose operating voltage in most cases exceeds 1.5 V require a power source of at least 3.2 V. In this case, a blocking generator is used for connection on resistor, transistor and transformer
- Connect to 5 V. This connection of the LED involves connecting a resistor with a resistance in the range of 100-200 ohms.
- Connect to 9 V. This power supply is extremely rarely used to connect LEDs. Most often, three diodes are connected in series with an operating current of 20 mA.
- Connectionto 12 V. Includes determining the type of unit, finding the rated current, voltage and power consumption. In the case of such a connection, it is necessary to use a resistor, which is placed on any part of the electrical circuit.
- Connection to 220 V. With this connection, it is necessary to limit the level of current that will pass through the LED, as well as lower the level of the reverse LED voltage, since only in this way will it be possible to prevent a breakdown. The current level is limited by resistors, capacitors or inductors.
Let's focus on connecting to a 220 V network.
The principle of connecting to high rates
How to connect an LED to a 220 V network? As already mentioned, for the optimal assembly of the device, a driver is needed, since in order to make such a connection and so that the devices can work stably, it is necessary to reduce the voltage amplitude and reduce the current strength, as well as convert the AC voltage to DC. A divider that has a resistor or capacitive load, as well as various stabilizers, can help solve this problem.
Lamp switch
How is the LED switch connected? For us, the electric switch in the apartments has not been a curiosity for a long time. However, progress does not stand still, and manufacturers of lighting equipment have already improved the switches we are used to by providing them with LED backlighting. Suchdevices provide for their illumination when turned off. During the day, such an improvement, of course, is imperceptible. But at night, this seemingly trifle is extraordinarily relevant. Connecting a switch with an LED is not a difficult task, since it is carried out according to a very simple scheme. However, safety precautions require certain nuances to be observed.
As you can see from the presented diagram, the device consists of only two elements - a resistor that limits the current, and, in fact, a light source. The complexity and peculiar paradox lies in the fact that the LED is placed in a 220 V AC switch. At the same time, the LED itself is designed for a constant voltage from 2 to 12 V. However, when the current strength is much greater than this section of the connection circuit is able to pass, the excess energy is converted into heat. And if there was no resistor in front of the LED, then the current passing through it would simply evaporate the diode crystal. It's all about the resistor, which cuts off most of the current.
Work algorithm
Connecting the LED in the switch is carried out in several stages:
- Completely turning off the power supply.
- We disassemble the switch, we connect elements to its terminals in accordance with the above diagram.
- In the switch panel with a thin drill, drill a hole for the output of the LED.
- Assembling the switch.
- Restoring power supply.
- Using the device.
