The light emitting diode (LED) is a kind of direct current is injected into the light emitting device, semiconductor crystal stimulated electronic from high level to low level recovery, emit the photons, which is commonly referred to as spontaneous emission transition. When the LED PN junction with forward bias, the injected minority carrier and majority carrier (the electron and hole) composite light. It is worth noting that, for a large number of high-energy particles in their respective spontaneous emission in a row angular frequency v =Eg/h wave, but no fixed phase relationship between the columns of light, can have different polarization directions, and each particle emitted light along all possible the direction of propagation, this process is called spontaneous emission. The emission wavelength can be said to lambda (m) =1.2396/Eg (eV)
The light emitting diode (LED) by P GaAs, phosphide material. There is a junction inside it, also having a single conductivity, but the light emitting diode in the forward conduction will be light, the brightness of the light with the conduction current increased, color light with wavelength.
Universal light emitting diode multimeter detecting method:
Measure R * 10K with Multimeter
Using a pointer type multimeter with * 10K block, the quality of the LED can be roughly judged. Normally, the diode forward resistance is ten to 200K, reverse resistance to /. If the forward resistance value is 0 or is unknown, the reverse resistance value is very small or 0, then it is easy to damage. The method of detection can not see the luminous status of the luminous tube on the spot, because the * 10K barrier can not provide larger forward current to the LED.
Measure with two multimeter
If you have two pointer multimeter (preferably the same type), you can better check the light-emitting diode light. Connect one of the multimeter's "+" terminals to the "-" terminal of another table with one wire. The remaining "-" pen is connected to the positive electrode (P area) of the LED, and the remaining "+" pen is connected to the negative electrode of the LED (N area). Two pieces of multimeter are set with * 10 block. Normally, the light is normal when connected. If the brightness is very low, and even does not emit light, the two meters can be allocated to * 1. If it is still dark and even does not emit light, the performance of the LED is poor or damaged. It should be noted that two multimeter cannot be placed at * 1 at the beginning of the measurement so as to avoid excessive current and damage to the led.
External auxiliary power measurement
The light and electric characteristics of LED can be measured more accurately by means of 3V regulator or two series connected dry cell and multimeter (pointer or digital). To do so, connect the circuit as shown in figure 10. If the VF is measured between 1.4 and 3V, and the brightness is normal, it can be explained that the luminescence is normal. If the measured VF=0 is 3V or VF, and do not light, that light emitting tube has been bad. The light emitting diode (LED) is a kind of direct current is injected into the light emitting device, semiconductor crystal stimulated electronic from high level to low level recovery, emit the photons, which is commonly referred to as spontaneous emission transition. When the LED PN junction with forward bias, the injected minority carrier and majority carrier (the electron and hole) composite light. It is worth noting that, for a large number of high-energy particles in their respective spontaneous emission in a row angular frequency v =Eg/h wave, but no fixed phase relationship between the columns of light, can have different polarization directions, and each particle emitted light along all possible the direction of propagation, this process is called spontaneous emission. The emission wavelength can be said to lambda (m) =1.2396/Eg (eV)
The light emitting diode (LED) by P GaAs, phosphide material. There is a junction inside it, also having a single conductivity, but the light emitting diode in the forward conduction will be light, the brightness of the light with the conduction current increased, color light with wavelength.
Universal light emitting diode multimeter detecting method:
Measure R * 10K with Multimeter
Using a pointer type multimeter with * 10K block, the quality of the LED can be roughly judged. Normally, the diode forward resistance is ten to 200K, reverse resistance to /. If the forward resistance value is 0 or is unknown, the reverse resistance value is very small or 0, then it is easy to damage. The method of detection can not see the luminous status of the luminous tube on the spot, because the * 10K barrier can not provide larger forward current to the LED.
Measure with two multimeter
If you have two pointer multimeter (preferably the same type), you can better check the light-emitting diode light. Connect one of the multimeter's "+" terminals to the "-" terminal of another table with one wire. The remaining "-" pen is connected to the positive electrode (P area) of the LED, and the remaining "+" pen is connected to the negative electrode of the LED (N area). Two pieces of multimeter are set with * 10 block. Normally, the light is normal when connected. If the brightness is very low, and even does not emit light, the two meters can be allocated to * 1. If it is still dark and even does not emit light, the performance of the LED is poor or damaged. It should be noted that two multimeter cannot be placed at * 1 at the beginning of the measurement so as to avoid excessive current and damage to the led.
External auxiliary power measurement
The light and electric characteristics of LED can be measured more accurately by means of 3V regulator or two series connected dry cell and multimeter (pointer or digital). To do so, connect the circuit as shown in figure 10. If the VF is measured between 1.4 and 3V, and the brightness is normal, it can be explained that the luminescence is normal. If the measured VF=0 is 3V or VF, and do not light, that light emitting tube has been bad.
