what is an infrared light emitting diode?

Last Update Time: 2018-10-26 16:45:24

how to detect a laser diode?

determine the order of the arrangement of the pins.The multimeter is placed in the R*1 thousand euro file.According to the method of detecting the normal diode and the reverse resistance,the arrangement order of the laser diode can be determined.The forward voltage drop of the laser diode LD is larger than that of the ordinary diode,so the forward resistance is large,and the multimeter pointer meter is deflected to the right.And the right deflection is large,and the reverse resistance should be infinite.The resistance is infinitely large.The forward voltage drop of the PD diode is small,so the forward electric pointer is directed by a small multimeter.

discriminant method of laser diode

measuring PD reverse resistance to diode LD plus voltage PD resistance should be significantly reduced,indicating LD.PD all are good.

increase the voltage of diode LD and reduce the luminescence at 1.6V;when 2.8V,the luminescence is stronger and the current is measured.If in 35~ 60mA,light is strong,then it is good,weak is bad,no light is bad.

Observe with CD-ROM,do not install CD-ROM,dismantle the rear cover,and observe whether there are dark red spots during the visit.

using a dedicated laser power detector to directly detect the mirror,aging when the general power is less than 0.1mW.

A digital multimeter is used to monitor the voltage drop of the load resistance in the driving circuit and calculate the current.When the current exceeds 100mA,the dimming power control potentiometer has a very small change in current,and it will break or open if the current is too large or too small.

Remove laser diode,measure positive and reverse resistance.In normal,the reverse is infinity,and the forward is 20~ 30k2.If it is greater than 75k2,the characteristic is not good;if it is greater than 90k2,it can not be used (this method is suitable for selecting laser diodes).

what is an infrared light emitting diode?

The common infrared light emitting diodes (abbreviated as infrared light emitting diodes) have two kinds of dark blue and transparent,similar to ordinary light emitting diodes. Figure 5-20 shows the structure and symbol diagram of infrared light emitting diodes. Because the infrared light emitting diode usually uses a transparent plastic package,the electrode in the shell is clearly visible;the inner electrode is larger than the negative,and the narrower is the positive pole.The fully plastic encapsulated infrared light emitting diode has a small plane on the side,a negative electrode near the small plane, and a positive pole on the other.

The infrared LED operates under the forward voltage,the working voltage is about 1.4V,and the working current is generally less than 20mA.In the application,the finite current resistance should be set in the circuit.

In order to increase the distance of infrared ray,infrared LED usually operates in pulse state.When the infrared light emitting diode is used to transmit infrared to control the controlled device,there are corresponding infrared light and electric converters in the controlled device,such as the infrared receiving diode,the photosensitive transistor and so on.In practice,photodiodes are usually used for infrared transmitting and receiving.

There are two ways to transmit and receive infrared light:one is direct radiation;the other two is reflective.The direct radiation means the light emitting light directly irradiate the receiving tube;the reflective finger light tube and the receiving tube are listed together.When the infrared light emitted by the light emitting tube meets the reflection,the receiver receives the reflected infrared ray to work.