The light emitting diode is connected to a 220V circuit

Generally, the resistance of the light-emitting diode as the mains power supply indicator string is more than a few hundred ohms, although it cannot reach a current of 10mA, it can also emit light.

The choice of resistance should take into account the power of the resistance, such as the main building reaches 10mA current, the resistance should be r=220 k, ignoring the light-emitting diode voltage drop (correct what was said upstairs, the light-emitting diode forward voltage drop is above), the resistance power p=220 22000= w, you can imagine how big the resistance is, how hot it is, and how much energy is wasted;

Secondly, it is used in AC mains, the damage of the reverse voltage to the light-emitting diode, and increasing the resistance can reduce the reverse breakdown current to protect the light-emitting diode, such as adding the diode (IN4007) then it is another matter;

As long as the LED energy is realized, the energy consumption is not only low, but also the service life is high.

PS: The on-voltage drop refers to the voltage on the original during normal operation.

One, two, three, four, five, hand play is very hard =-

The on-voltage drop of the light-emitting diode is about, the normal working current is a few milliamperes to more than ten milliamperes, and the voltage drop is negligible in the voltage of 220, and the current is 220 1200=, which exceeds the normal working current, so it will burn out.

The calculation method, because of the unidirectional nature of the diode, the effective value of the voltage after connecting to the mains is 220V 2=110V, and the method of calculating the resistance (taking red as an example) is (, the blue is easy to break down, and a 1N4007 is connected in reverse parallel according to the current direction of the light-emitting diode

Updated on November 7, 2019.

According to the actual use of the indication with LED, 2mA can work, when used to 20mA, the current limiting resistor power consumption is too large, the calculation formula is changed to (, in fact, 51-100K resistor is more appropriate.

The LEDs are connected to 220 volts with a 14-point 5 kΩ resistor. Resistance is a physical quantity, in physics, it represents the magnitude of the conductor's resistance to the current, the greater the resistance of the conductor, the greater the resistance of the conductor to the current, different conductors, the resistance is generally different, and the resistance is a characteristic of the conductor itself.

Light-emitting diodes are referred to as LEDs, which can emit visible light when electrons and holes are compounded, so they can be used to make light-emitting diodes, which can be used as indicator lights in circuits and instruments, or to form text or digital displays. Gallium arsenide diodes glow red, gallium phosphide diodes glow green, silicon carbide diodes glow yellow, and gallium nitride diodes glow blue.

The contents of the resistor

Resistance will result in a change in the flow of electrons, the smaller the resistance, the greater the flow of electrons and vice versa, while superconductors have no resistance. If the superconducting phenomenon is applied to practice, it will bring great benefits to human beings, and if superconducting materials can be used in power plant power generation, transportation of electricity, storage of electricity, etc., the power consumption caused by resistance can be greatly reduced.

If the electronic components are manufactured with superconducting materials, because there is no resistance, there is no need to consider the problem of heat dissipation, the size of the components can be greatly reduced, and the miniaturization of electronic devices can be further realized, and the resistance of different conductors can also be divided into two types according to their different properties, one is called linear resistance or ohmic resistance, which satisfies Ohm's law, and the other is called nonlinear resistance, which does not meet Ohm's law.

LEDs are direct, so rectifiers must be used, because they are not of the same nature!

A: 1100 2V LEDs are arranged in series into 20 series, and each series is connected with 5 2V LED sock clusters.

2.Connect 20 positive terminals in series together and then connect to a unified positive power supply;

3.The 20 negative poles in series are connected together, and then the Zheng chain is connected to a unified negative electrode power supply.

First of all, it can be determined that the voltage drop of the light-emitting tube (on ordinary electrical equipment, the diameter is generally 3 5mm) is controlled at about 2V, and the current should not exceed 10mA.

In the PN junction of some semiconductor materials, when the injected minority carriers are recombined with the majority carriers, the excess energy is released in the form of light, thus directly converting electrical energy into light energy.

The PN junction is added with a reverse voltage, and a few carriers are difficult to inject, so they do not emit light. When it is in the forward working state (that is, the two ends add the forward voltage), when the current flows from the LED anode to the cathode, the semiconductor crystal emits light of different colors from ultraviolet to infrared, and the intensity of the light is related to the current.

Summary. Dear, how to connect 25 LEDs is as follows: 1The first thing is to connect the light-emitting diode, first find the rated working current range according to the light-emitting diode manual, select the working point, and get the junction voltage value!

2.Next, we need to subtract the junction voltage from the existing power supply voltage, and then find the size of the current limiting resistor according to the working current, and connect a resistor in series to use it!

How to connect 25 LEDs.

Dear, how to connect 25 LEDs is as follows: 1The first thing is to connect the light-emitting diode, first find the rated working current range according to the light-emitting diode manual, select the working point, and get the junction voltage value! 2.

Next, we need to subtract the junction voltage from the existing power supply voltage, and then find the size of the current limiting resistor according to the working current, and connect a resistor in series to use it!

Kiss, the specific teacher will share with you the connection method 1Kiss, resistor connection: 1 guardrail light with 108 white LEDs, each LED preset current of 13 14mA.

1) Connection method of voltage source: (power consumption method 1: 6 lamps per group plus current limiting resistor, and then 18 groups, power supply 24V, 240mA 2.)

Kiss it, and then the second method is: 3 lamps per group plus current limiting resistor, and then 36 groups, power supply 12V, 480mA Note: Current limiting resistance (power supply voltage series LED lamp group voltage) Preset LED light flow Oh!

2) Kiss it, and there is the connection method of using a constant current source: (power consumption, power saving 20%) Oh!

Four 1N4007 can be used as bridge rectification and then series 12K 2W resistors, red and blue can be used with the same resistance, no actuarial calculation;

In addition: the red light-emitting tube can be directly connected to the mains in series with a 12K resistor;

It is best to connect two inverting resistors in parallel and then connect to the mains in blue, because blue is easy to break down.

Light-emitting diodes are abbreviated as LEDs. It is made of compounds containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N), etc. When electrons recombine with holes, they emit visible light, which can be used to make light-emitting diodes.

A diode, a device with two electrodes that allows current to flow in a single direction, is used in many electronic components to apply its rectification function. Varactor diodes (VAFIC diodes) are used as electronic tunable capacitors.

The current directivity of most diodes is often referred to as "rectifying".

The most common function of a diode is to allow only current to pass through a single direction (known as forward bias) and to block it in reverse direction (known as reverse bias). Therefore, the diode can be thought of as an electronic version of the check valve.