enter image description here Hello all, I'm working on RGB LED strip SMD 5050 5m This all setup is working on 12v 2A with about diagram. I want to use same connection with 100m of LED strip using Arduino. Please support regarding this topic. H/W details : Arduino uno Hc-05 bt module 12v 1.2 amp supply Td140 pnp transistor SMD 5050 LED strip 60 LED/m

  • Where do you want the 100m of wire? Between the PSU and the LEDs? Between the Arduino and the transistors? Between the transistors and the LEDs? Between the Arduino and the bluetooth transceiver?
    – Majenko
    Oct 22, 2018 at 20:04
  • I want to use 100m LED strip
    – Dr geek
    Oct 22, 2018 at 20:24
  • 100m of 60LED/m? i.e. 6000 RGB LEDs or 18000 LEDs?
    – Craig
    Oct 22, 2018 at 20:38
  • You cannot drive 100m of LED strip from one side. That would be 200A. Even at only 5m I needed to provide the power at both sites to prevent the strip from getting too hot. So you would have to provide power also every few meters into the strip.
    – chrisl
    Oct 22, 2018 at 20:55
  • there's a limit to how many LEDs you can address w/WS2812, i don't recall, but it's far less than 6000
    – dandavis
    Oct 23, 2018 at 16:48

1 Answer 1


100 Meters of 5050 SMD strip LEDs will require roughly 120-200 amps. However, you cannot drive a 100 meter strip from a single power supply. The thin copper traces in the LED strip can only handle so many amps before they become too hot (your LED strip would melt like ice cream on a hot summer day). This is why led strips are usually limited to 5 meters (~5A). You would need separated strips and power supplies for the 100 meters worth.

You have the correct idea with your circuit for turning the leds on/off (in fact the wiring is correct) but the transistors you plan on using are the wrong type. To switch the LEDs to ground you would need a low side switch, which would be a NPN transistor. Be careful however, transistors typically switch currents less than 1 amp. For higher power applications I would suggest using a N-channel Mosfet. A quick search on Sparkfun turns up the FQP30N06L, which is capable of handling 30A (with a heatsink, probably less than half without), and is also logic-level, meaning it can be driven with a 5 volt source (Arduino I/O pin).

Keep in mind, whatever current your LED strip draws, the ground switch (NPN transistor, N-Channel MOSFET, relay) must be able to handle the same current.

Good luck with your circuit!

Not the answer you're looking for? Browse other questions tagged or ask your own question.