# 5V to 3V Resistor Change.

Hi, To All That Read This.

What I would like some help on is. I came across this (Arduino EMF Detector).

It works great, but I would like to use A Moteino. Moteino is Arduino clone.
But the Moteino is running at 3.3 volts.

The Arduino is running at 5 volts. The resistor used on the project is (3.3M).
What I need to know is if, I am doing the Ohm’s Law Calculator, right?

Arduino EMF Detector

`````` Voltage (E) = Current (I) * Resistance (R)
Power (watts) = Voltage (E) * Current (I)

Voltage (E): 5
Current (I): 0
Resistance (R): 3.3m      Megaohms
Power (P): .000001
``````

Moteino

`````` Voltage (E) = Current (I) * Resistance (R)
Power (watts) = Voltage (E) * Current (I)

Voltage (E): 5
Current (I): 0
Resistance (R): .9m	 Megaohms
Power (P): .000001
``````

So at 3 volts, the resistor I need to use is (White Black Yellow Gold) = .9 Megaohm or 900K

Your over thinking this circuit. The 3.3m is high imedance and not really critical. Anyhthing above 1M should be fine, but 2-3M would be okay as well.