I have an Arduino wired to ws2812b with 10 100uF capacitors and 2 1000ohm resistors(picture). When I'm plugging 5v power supply everything is working when I plug 9v battery everything is fine but when I'm plugging 12v power supply in one moment leds stops.(NeoPixel standardtest example. How I can power the ws2812b by 12venter image description here

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  • I'm rather sure, that WS2812B LEDS are 5V devices, so powering them with 12V will probably destroy them. You didn't show us, how you connected the power supply. Please don't try to power the strip through the Arduino. It will very likely kill the voltage regulator or the protection diode or both on your Arduino. – chrisl Dec 26 '19 at 13:43
  • Your regulator on the Arduino is probably overheating. – Majenko Dec 26 '19 at 14:38

The regulator on an Arduino is likely analog. On this Arduino Uno the regulator is an analog NCP1117ST50T3G as seen in this schematic. On page 2 of the NCP1117ST50T3G spcification it is stated:

Internal thermal shutdown protection limits the die temperature to approximately 175°C. Proper heatsinking is required to prevent activation.

Being an analog power regulator, the difference between the input voltage and the regulated output voltage eventually turns into heat. This may explain why a 9 volt source may work (drop is only 9V - 5V = 4V) while a 12 volt source may not work (drop is 12V - 5V = 7V).

Consider using a 5 volt power source avoiding the Arduino analog power regulator. Or, if the only source is 12 volts (for example an automobile), consider using an external switching or buck power supply to convert the 12 volt down to 5 volts and again avoiding the Arduino analog power regulator. Lastly, it should be possible to still power the Arduino with 12 volts and use its internal power regulator to only power the Arduino. Then independently power the LED strip using an external power regulator. This last option will likely have the benefit of eliminating the capacitor bank seen in the question and associated components.

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See if arduino works with strips disconnected Assuming that you are connecting your 12V to the breadboard Do not try to use Arduinos voltage regulator to supply something this massive as LED strip (if you did, then arduinos voltage regulator would be burned by now)

If arduino works with strips disconnected If it does: check the voltage of the strip if its not written check if each LED has its own resistor. If it doesn't you may see Two or three LED per resistor in series That usually means 12V This would mean that LEDS would have been dim when on 5V Then you need to drop the voltage(difficult, I am not sure if even LM350A is strong enough)you can try putting 100 ohm resistor before and across the LED strip this will not be sustainable, but might light the LEDS bit for a bit.

if it works with strips disconnected: If it doesn't: Does arduino start? If it does. see first half of this message If it doesn't: Does arduino start when connected via USB? (Disconnect from breadboard for this test) if it doesn't board is damaged if it does you have burned your voltage regulator. I am not sure what are those capacitors there for. LED's arent very picky about the supply and standard CE marked (legaly) 12DC supply would be suitable for both arduino and the strip supply out of the box

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