Electronic – arduino – Beyond board power, understanding multiple power supplies and loads in a circuit

arduinopower supply

I have a project I am looking to power where the secondary load is more than my Arduino can provide amp-wise. I need to know the simplest way to power the whole system. I will be powering the Arduino and a 5v 1.2amp load. Diagrams I have seen show a common ground with two power supplies but I don't know the math for anything beyond a simple circuit. Links to other resources are welcome with all answers. I am looking to learn more about power and circuits in general so more info is better.


If I use one supply, how should I design the circuit? e.g. Series or Paralell. Also, how would I go about determining the requirements for that power supply?

Best Answer

Without knowing more specifics about your particular set-up, here are some ideas:

The best and safest option would be to use one strong (1.5A or 2A) regulated power supply that powers both the microcontroller (arduino) and the heavier load.

It would also be possible to use two separate supplies, but then, you would have to make sure that the stuff connected to the microcontroller will not back-supply the I/O pins, possibly causing damage to the microcontroller (see: clamp diodes), i.e. you would have to make sure that both supplies provide almost exactly the same voltage (within +/- 0.3 V).