Powering arduino sensors - what resistor should I use? Recently I have asked a question, why my sensors do not work on external power supply (link). I have found out, that I was limiting the current too much with the resistors. I have tried using two sensors:


DHT22, rated at 1.5mA max (picture of my module) 
BH1750, rated at 190uA max (picture of my module)


My logic is, if they are rated at that current, I should put a resistor in the Vin, to restrict the current to given value. But it turned out that I was wrong, because they started working only after I removed my resistors.

My questions is - should I put a resistor in there? If yes, then how do I know what resistance should I have, if the data sheet values are misleading?
You should have NO resistor.

The datasheet states the current values the device will pull from the supply. Supplies DO NOT PUSH CURRENT.

Remove all resistors. 

As long as the voltage is correct and the supply can provide at least as much current as all devices combined want to use then it will work.