Arduino nano analog pin sink current

Hello everybody.

I'm wanting to detect a voltage level (up to approx 5V) on the arduino nano, so shall be connecting to an arduino analog pin configured as an input. Do I need to put a resistor before the analog pin to limit the current that the arduino will sink to something like 20mA (considering each arduino pin can sink/source 40mA)?

Thanks.

When configured as inputs the input impedance is around 100 Meg. Essentially, no current flows into an input (under normal operating conditions).

If you exceed Vcc (or if the input signal goes negative) the internal protection diodes start conducting and you should add a resistor to limit the current.

Where are you getting your voltage reference from? The default is Vcc.

Mark

Only outputs sink current, inputs do not.
See this:-
http://www.thebox.myzen.co.uk/Tutorial/Inputs.html

Grumpy_Mike:
Only outputs sink current, inputs do not.

I know that is correct - but it does sound perverse.

...R

Thank you everybody. :slight_smile: