!!!Sunlight Killed my Zebra Light H-30!!!
- Thread starter kabkbak7321
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my neighbours will be soo curious. 
Flashlight Aficionado
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or if you shined it at a mirror at point-blank range.
MrGman
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Semiconductors to a degree are all photo sensitive. I have opened up many a transistor in a metal can and while testing it electrically, if I had it under the microscope light the reverse biase leakage current went up where I could easily see it on the Curve Tracer I was using to do the tests. Sometimes I would be probing a die under the microscope and I could make the reverse leakage currents come and go at will by modulating the light.
Light Emitting diodes are worse. When they are forward biased the p/n junction being biased on gives off light from the current and creates a voltage drop. If there is light coming in from a strong source, it is creating internal current in the opposite direction. Since it is doped with elements that give light, they also receive light and create electrical energy. It will reduce the forward bias and make the LED go out if the external source is stronger than the forward current induced light or enough to reduce the diode bias to less than one diode drop for that diode type. So if it starts turning on at 2.9V and is normally sitting at 3.3V for "low mode" getting enough reverse current to make it go down by 0.4V back under 2.9V low and behold your diode is turned is not emitting light. That doesn't mean there is no current flow. There are majority and minority current carriers in the p/n junction. The forward bias changing the width of the p/n junction, turning it on and creating light acts as a gate that makes it impossible to turn itself off from its own light energy, otherwise it would obviously not work. If you put that thing under a strong source through a magnifying lens focused on the die, you could probably make it go off even in high mode. It is not too much different from a solar cell specifically designed to take light coming in to make electricity. These are all diodes with different dopants in the p/n junction to make them do a specific task.
You might also destroy the die by creating excessive leakage currents when it should have been forward biased destroying the PN junction, if putting too much light into it while trying to turn it on at the same time using the magnifying glass so I don't recommend actually doing it. Maybe/maybe not. You might also burn out the phosphor doing this and be very unhappy if your light output falls way off and starts looking blue.
You could simply google "dopants in light emitting diodes" and "dopants in solar cells" for more "enlightenment" as to how and why these things work and why it has some photo sensitivity, its not a deep dark military secret.
Light Emitting diodes are worse. When they are forward biased the p/n junction being biased on gives off light from the current and creates a voltage drop. If there is light coming in from a strong source, it is creating internal current in the opposite direction. Since it is doped with elements that give light, they also receive light and create electrical energy. It will reduce the forward bias and make the LED go out if the external source is stronger than the forward current induced light or enough to reduce the diode bias to less than one diode drop for that diode type. So if it starts turning on at 2.9V and is normally sitting at 3.3V for "low mode" getting enough reverse current to make it go down by 0.4V back under 2.9V low and behold your diode is turned is not emitting light. That doesn't mean there is no current flow. There are majority and minority current carriers in the p/n junction. The forward bias changing the width of the p/n junction, turning it on and creating light acts as a gate that makes it impossible to turn itself off from its own light energy, otherwise it would obviously not work. If you put that thing under a strong source through a magnifying lens focused on the die, you could probably make it go off even in high mode. It is not too much different from a solar cell specifically designed to take light coming in to make electricity. These are all diodes with different dopants in the p/n junction to make them do a specific task.
You might also destroy the die by creating excessive leakage currents when it should have been forward biased destroying the PN junction, if putting too much light into it while trying to turn it on at the same time using the magnifying glass so I don't recommend actually doing it. Maybe/maybe not. You might also burn out the phosphor doing this and be very unhappy if your light output falls way off and starts looking blue.
You could simply google "dopants in light emitting diodes" and "dopants in solar cells" for more "enlightenment" as to how and why these things work and why it has some photo sensitivity, its not a deep dark military secret.
Last edited:
TOTC
Newly Enlightened
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Thanks, MrGman. That's some fascinating stuff that I didn't know before
