EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: DW1961 on July 12, 2020, 09:20:04 pm
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What happens or can happen when you reverse polarity of 12V LED strip lights?
I've read where some are not protected from RP, but tehn read that diodes don't flow backwards, acting as a sort of resistor. Then I read some diodes can be damaged by reverse polarity becasue their resistance isn't strong enough.
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The strip itself for 'Dumb' single colour or RGB ones should be reverse polarity resistant. To run from 12V efficiently the LEDs will be arranged in series strings of three (or more if the individual Vf is under 3V) + a dropper resistor so no LED will see a reverse voltage over the 5V limit permissible for most types of LED.
However if its made of smart individually digitally controllable LEDs, reverse polarity will instantly destroy them, and reverse polarity will destroy unprotected controller boards for 'dumb'LED strips.
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That's probably why the standard DLED plugs in a computer are plugged out for one of the pins? (No way to reverse them?)
Thanks for the reply. I have read that if you reverse the polarity on the dumb 12V LED strips, they just don't work. No damage.
But, are you saying if you plug an RGB strip into a controller, like the cheap ones you get from Amazon, it will instantly destroy the controller--what boards are unprotected these days?
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No, reversing a dumb RGB LED strip shouldn't damage the controller, but reversing the supply to the controller will kill it unless its got extra cost parts to provide reverse polarity protection.
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No, reversing a dumb RGB LED strip shouldn't damage the controller, but reversing the supply to the controller will kill it unless its got extra cost parts to provide reverse polarity protection.
Interesting. I'll definitely remember that if I am working with bare wire supply to controllers. Thanks.