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I am looking at using small lengths of single colour 12v LED strip (2835) in a project, maybe just 1 or two sections i.e. 3 or 6 LED's. I have tried single 2 pin LED's and they aren't bright enough.

My question is if I wanted to use say a 12 V 500 mA wall wart, would it damage/blow the pieces of strip because the current was way over the top. Or would the strip just pull what it needed and the built in strip resistors handle the overcurrent?

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  • \$\begingroup\$ When you match voltage with more power than load, no issues but if overloaded supply will shutdown. BTW I have 20mA 5mm LEDs way brighter than 5050 but only 30deg. \$\endgroup\$
    – Tony Stewart EE75
    Commented Mar 18, 2021 at 18:25
  • \$\begingroup\$ If the wall wart says something like "OUTPUT: +12V⎓500mA", then that means it outputs a regulated 12V and is rated to supply up to 500mA (current supplied depends on load connected). There are several levels of quality for AC/DC adapters so 12V may vary for low quality supplies. To your LED strip, add a resistor or diode in series to vary the load and current \$\endgroup\$
    – Ernesto
    Commented Mar 18, 2021 at 19:55
  • \$\begingroup\$ Well, if your LED strip is specified as 12V, then OK to use a wall wart. But there are other complications. Nowadays power LEDs are usually specified by current, eg. "350mA, 1W", or "700mA 3W", then it is more efficient to use "constant current" source to drive the LED. You might like to see how I am using constant currents LED drivers to play with 350mA LEDs: How can Rpi Python PWM GPIO pins control brightness of white LED strips of 1W 350mA? raspberrypi.stackexchange.com/questions/122187/… \$\endgroup\$
    – tlfong01
    Commented Mar 19, 2021 at 1:31
  • \$\begingroup\$ I usually recommend this LED newbie friendly tutorial: 1W 350mA LED Tutorial: components101.com/diodes/1-watt-led.Have a great LED project. Cheers. \$\endgroup\$
    – tlfong01
    Commented Mar 19, 2021 at 1:38

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LED strips are voltage driven devices. You need to pick a 12v power supply that can source at least as much current as the strip requires. More is ok, less is not.

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  • \$\begingroup\$ So if I used say a 4a instead of the recommended 2a it would only draw the current needed i.e. 2 amps ? \$\endgroup\$
    – Samsnail
    Commented Mar 18, 2021 at 22:23
  • \$\begingroup\$ @Samsnail Correct. \$\endgroup\$
    – user1850479
    Commented Mar 18, 2021 at 22:50
  • \$\begingroup\$ Note that while LED strips need a specific voltage, this is not the same as LEDs by themselves The strips have extra parts on them to make this work. \$\endgroup\$
    – Stack Exchange Supports Israel
    Commented Mar 19, 2021 at 11:22

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