If the MOSFET is off (ie. the Arduino pin is LOW) then what current would you expect to flow between Drain and Source? I know "not much" but are we talking maybe 10 nA?
10uA is far less than the self-discharge rate of most batteries - you can ignore FET leakageat room temperature.
10uA is far less than the self-discharge rate of most batteries - you can ignore FET leakageat room temperature.In the diagram the gate current limiting resistor is shown as 10 ohms - no use for the Arduino,150 ohms would be a more suitable value (keeps Arduino pin current within spec - less than40mA)
Just out of curiosity, what is the basis for suggesting 150R?
So the MOSFET would temporarily act as a complete short on the output pin?
So the MOSFET would temporarily act as a complete short on the output pin? And thus we need to limit the current, is that it? So that would limit the current to 33.3 mA?
Yes, but the total *area* of all those MOSFETs are probably less then the area of the power device, which is what counts - to a first order - in leakage.
Drain leakage of a MOSFET with a low threshold :1 uA at 25 degrees C20 uA at 150 degrees Chttp://www.nxp.com/documents/data_sheet/PMV20XN.pdf