I need my 5v 10 amp power supply to power both my LED strip and arduino.
I will have the LED strip directly wired to the power supply, then for the arduino I have two ideas - either cut a USB cable and connect its power/ground wires to the power supply, or wire the 5v/ground pins of the arduino to the power supply.
My question is would 10 amps be too much to give an arduino through either of these two ways? Using the 5v pin to power the arduino is unregulated, but I'm not sure if this is relevant to amps or just volts? My understanding is that the arduino and components plugged into the arduino will only draw as much amps as they need. I know the strip can handle the amps, but can the arduino? It will only be connected to a basic LCD display and joystick to control the colors.

  • \$\begingroup\$ Thought experiment: a car battery can supply hundreds of amps. What happens when you connect a 6 watt tail lamp that only requires half an amp? \$\endgroup\$ – Transistor Dec 26 '18 at 0:52
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    \$\begingroup\$ @Transistor I have no clue that's what I'm trying to find out but without actually doing it \$\endgroup\$ – Frobot Dec 26 '18 at 0:53
  • \$\begingroup\$ Each load only draw the current it requires. The 6 watt lamp only drawers half an amp despite the battery having a much higher capability. Your microcontroller will only draw the current it requires from the 10 amp supply. \$\endgroup\$ – Transistor Dec 26 '18 at 0:56
  • \$\begingroup\$ And you are sure this is still safe using the unregulated 5v pin to power the arduino? \$\endgroup\$ – Frobot Dec 26 '18 at 1:03
  • \$\begingroup\$ LEDstrips cannot cascade 10Amps, so each 5m strips must fed separately with heavy wire. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Dec 26 '18 at 4:32

My understanding is that the arduino and components plugged into the arduino will only draw as much amps as they need.

Your understanding is correct. You can go ahead with your plan.

I'm not sure what you mean when you say that connecting the Arduino to the power supply with an USB cable and connecting it with wires are two different options. Either way you're connecting the Arduino to the power supply.

You can read more details in this reference question here on Stack Exchange: Choosing power supply, how to get the voltage and current ratings?

  • \$\begingroup\$ they are two totally different things, whether the result is the same or not. One goes through the USB port of the arduino and the other uses the 5v/ground pins and doesn't get regulated. \$\endgroup\$ – Frobot Dec 26 '18 at 1:24
  • \$\begingroup\$ @Frobot Which Arduino do you use? The +5V from USB is not regulated on the UNO, it goes straight to the microcontroller. \$\endgroup\$ – pipe Dec 26 '18 at 1:27
  • \$\begingroup\$ I use the uno but have found several different places that stress there is a difference between powering with the USB/DC jack and directly with the 5v pin \$\endgroup\$ – Frobot Dec 26 '18 at 1:47
  • \$\begingroup\$ @Frobot There is a difference, but neither is regulated. \$\endgroup\$ – pipe Dec 26 '18 at 2:17

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