jeffpkamp:
I'm wondering if there will be any negative effects to my arduino if temporarily read a negative voltage using the analog pins? I am getting a current transformer that will put out -1 to 1 V based on current. I feel fine reading only half of the data and getting 0 for the negative values.
No input pin can tolerate out-of-range voltages, unless the current is limited to a small value. The input
protection diodes are tiny and can handle perhaps a mA or two at most for any length of time. Their job
is static discharge protection. If you add a 10k series resistor to the analog pin that will protect against a few
volts fine.
I'm not looking for how I could read it by floating the voltage up. I'm aware of how to do this, and probably will do this. I am just wondering if I will damage my micro controller by reading up to -1 V through the analog pin. I'm mostly looking for anyone who's ever tried this to save me the 3 bucks and tell me if I'll cook my chip :).
You pay 3 bucks for 2 resistors? Really?