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Topic: Issue with readAnalogVoltage() (Read 294 times) previous topic - next topic

viswapraveen

Hi,

Is it necessary to use the pins 5V or 3.3V or Vin of Arduino Uno in the external circuit in order to read analog voltage output from the external circuit using Arduino Uno ?

Pls advice.

Thanks

OldSteve

Hi,

Is it necessary to use the pins 5V or 3.3V or Vin of Arduino Uno in the external circuit in order to read analog voltage output from the external circuit using Arduino Uno ?

Pls advice.
Thanks
No. You only need to connect the UNO's ground to that of the external circuit, and ensure that the input voltage from the external circuit is not higher than the UNO's Vcc, (5V).
Please do not PM me for help. I am not a personal consultant.
And others will benefit as well if you post your question publicly on the forums.

viswapraveen


MarkT

And that its not lower than 0V...

The hard case is if the external circuit is powered up when the Arduino isn't, which
would cause the external signal to phantom-power the whole Arduino - a simple
if crude solution to this is add a 10k resistor in series with the signal source to
limit the current to safe levels.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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