Hi List, this is my fist approach to the electronic word I would like to connect the arduino with a Level Sensor here the data: Rated Power (max.) 100 W Switching Voltage 400 V Switching Current (max.) 1.0 A Carry Current (max.) 2.5 A Contact Resistance (max.) 150 mOhm @ 0.5V & 10mA

I now that i should calculate the Ohm Law but im completly lost:

1) mOhm means micro ohms or mega ohms? 2) Arduino shoud have 5V and this is the only part of equation clear

but to calculate the resistor where i find the amount of ampere used by the device ?