What is LED? What are the main parameters? What are the diode parameters?

LED is light-emitting diode, the main parameters are as follows:

Product parameters: voltage, system power, luminous flux, illumination, size.

Technical parameters: ballast type, built-in constant current drive, inductive ballast, life, illuminance, etc.

The main parameters of the diode.

1. Maximum rectifier current if: refers to the maximum forward average current allowed to pass through the tube during long-term operation. Because the current through the PN junction will cause the tube to heat up, the current is too large, and the heat generation exceeds the limit, which will cause the PN junction to burn out.

For example, the maximum rectification current for 2APL is 16mA.

2. Reverse breakdown voltage vbr: refers to the voltage value of the tube when it is reversed through breakdown. During breakdown, the reverse current increases dramatically, and the unidirectional conductivity of the diode is destroyed, or even burned out due to overheating.

The maximum reverse working voltage given on the general manual is about half of the breakdown voltage to ensure the safe operation of the tube. For example, the maximum reverse operating voltage of 2APL is specified as 2ov, while the reverse breakdown voltage is actually greater than 40V.

3. Reverse current IR: refers to the reverse current when the end of the tube breaks down, the smaller its value, the better the unidirectional conductivity of the tube. As the temperature increases, the reverse current increases dramatically, so be aware of the effect of temperature when using diodes.

4. Interpole capacitance CJ: The interpole capacitance of the diode includes barrier capacitance and diffusion capacitance, and the influence of junction capacitance must be considered in high-frequency application. Depending on the working state of the diode, the effect of the capacitance between the poles is also different.

LEDs are light emitting diodes.

The forward operating current of the chip is if:

It refers to the value of the forward current when the light-emitting diode emits light normally. In actual use, if should be selected as needed.

The forward operating voltage of the chip vf:

The operating voltage given in the parameter table is obtained at a given forward current. It is generally measured at if=20mA. The forward operating voltage vf of the light-emitting diode is in. When the outside temperature increases, the VF will decrease.

Characteristics: The relationship between the voltage and current of the light-emitting diode, when the forward voltage is less than a certain value (called the threshold), the current is extremely small and does not emit light. When the voltage exceeds a certain value, the forward current increases rapidly with the voltage and emits light.

4.Luminous intensity iv:

The luminous intensity of a light-emitting diode usually refers to the luminous intensity in the direction of the normal (or in the case of a cylindrical light-emitting tube, its axis). If the radiant intensity in this direction is (1 683) W Sr, it emits light 1 candela (symbol cd). Due to the small luminous intensity of LEDs, the luminous intensity is often used as a unit of candle light (Candela, MCD).

Angle of light:

6.Spectral half-width δ:

It indicates the spectral purity of the luminescent tube.

7.Half value angle 1 2 and angle of view:

1 2 refers to the angle between the direction in which the luminous intensity value is half of the axial intensity value and the axial (normal) direction of the luminous intensity.

8.Hologram: The angle calculated according to the three-dimensional angle of LED light, also called the plane angle.

9.Angle of view: refers to the maximum angle of LED light, according to different viewing angles, the application is also different, also called the angle of light intensity.

10.Half-shaped:

The angle between the normal 0° and the maximum luminous intensity value of 2. Strictly speaking, it is the angle between the maximum luminous intensity value and the maximum luminous intensity value of 2. The packaging technology of LED chips leads to the maximum luminous angle is not the light intensity value of normal 0°, and the deviation angle is introduced, which refers to the angle between the angle corresponding to the maximum luminous intensity and the normal 0°.

11.Maximum forward DC current ifm:

The maximum forward DC current allowed to be added. Exceeding this value can damage the diode.

12.Maximum reverse voltage vrm:

The maximum reverse voltage allowed to be added. Beyond this value, the light-emitting diode may be damaged by breakdown.

13.Working environment topm:

The ambient temperature range within which the light-emitting diode can operate normally. Below or above this temperature range, the light-emitting diode will not work properly and the efficiency will be greatly reduced.

14.Allowable power consumption pm:

The maximum value allowed to be applied to the product of the forward DC voltage at both ends of the LED and the current flowing through it. Above this value, the LED will heat up and be damaged.

Ordinary diodes, rectifier diodes, switching diodes, detection diodes, voltage regulator diodes, varactor diodes, etc.

The main parameters are forward current, forward conduction voltage drop, reverse breakdown voltage, operating temperature range, some high-speed diodes, junction capacitance and recovery time.

The main parameters of the diode: IDM maximum rectifier current, URM maximum reverse voltage, reverse saturation current IS, maximum working frequency FM, on-voltage ud.

There are four main parameters of a diode, namely the maximum forward current, the maximum reverse current, the highest reverse working voltage and the highest operating frequency.

Light-emitting diodes are referred to as LEDs and have the following characteristics:

1. Safety voltage.

LED uses a low-voltage power supply, and the power supply voltage is between DC 3-24V, which is a safer power supply than using a high-voltage power supply, especially suitable for public places.

2. Energy-saving model.

The energy consumption is about 80% less than that of incandescent lamps with the same light efficiency, and about 40% less than that of energy-saving lamps.

3. Strong applicability.

It is small in size, can be prepared into a variety of shapes, and is suitable for volatile environments.

4. Fast response time.

Its incandescent lamps have a response time in the millisecond range, and LED lamps have a response time in the nanosecond range.

5. There are many colors.

Light-emitting diodes have red, yellow, green, blue, and orange multi-color light emitting. The working voltage of the red fluorescent tube is small, and the working voltage of the red, orange, yellow, green, and blue LEDs of different colors increases sequentially.

6. **Low.

LED is becoming more and more popular, and due to the power-saving characteristics of LED, the places used will gradually increase.

1. Turn-on voltage drop VF: VF is the voltage drop at both ends of the diode when the diode is forward conducted, when the current through the diode is larger, the greater the VF; When the diode temperature is higher, the vf is smaller.

2. Reverse saturation leakage current IR: IR refers to the current flowing through the diode when the reverse voltage is added at both ends of the diode, and the reverse leakage current of the Schottky diode is larger.

3. Forehead Waiting Current IF: refers to the average current value converted according to the allowable temperature rise of the Schottky diode during long-term operation.

The above is provided by MDD Chenda Electronics.

The diode parameters of each brand model are different, but each first ear potato model manufactured by the manufacturer will have a corresponding parameter table, and some commonly used diode models have similar parameter values, different brands, and of course there are differences in performance.

Different diodes have different parameters. For example, TVS transient suppression diode, the specific parameters are: cut-off voltage, clamping voltage, breakdown voltage, leakage current, peak pulse current, peak pulse power, capacitance value, package form, etc.

1. Conduction voltage drop VF: VF is the voltage drop at both ends of the diode when the diode is forward conducted, when the current through the diode is larger, the VF is larger; When the diode temperature is higher, the vf is smaller.

2. Reverse saturation leakage current IR: IR refers to the current flowing through the diode when the reverse voltage is added at both ends of the diode, Schottky diode.

The reverse leakage current is large, and the choice of Schottky diode is to choose a diode with a smaller IR as much as possible.

3. Rated current.

if: refers to the average current value of the Schottky diode converted according to the allowable temperature rise during long-term operation.

The above is provided by MDD Chenda Electronics.