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   2 . Detecting infrared light-emitting diode

  MR16   Because infrared light-emitting diodes, which emit 1 ~ 3μm infrared light , the human eye can not . Usually single infrared LED transmitter power only a few mW, different models of infrared LED luminous intensity distribution angle is not the same . IR LED forward voltage drop is generally 1.3 ~ 2.5V. Precisely because of its infrared light emitted human eye can not see , so the use of the detection method of the visible LED can determine its PN junction is forward ,

 reverse electrical characteristics are normal, and it can not determine whether the normal light conditions . To this end , it is best to prepare a photosensitive device ( eg 2CR, 2DR -type silicon photocell ) as receiver. Metering with a multimeter across the battery voltage changes . Infrared LED to determine whether the forward current with an appropriate infrared light . The measurement circuit is shown in Figure 11 .

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Calculated from the known number of LED Power

Example: Rated output power is 10W power supply, rated forward current 20mA, power dissipation is 70mW conditions can configure the number of LED? According to the above formula ( that is to take the data obtained integer )

1 : For a constant drive: LED Flexi

The output power from the known way each LED string voltage calculation amount and the number of parallel branches