query regarding analog pin voltage???

Other Hardware General Electronics
1

Hi

I d like to know the maximum dc voltage that i can apply to a analog pin of an Arduino UNO , A0 to A5? is it 0-5V max?

when applying a voltage, is it right to connect the +ve from a regulated power supply to the analog pin and -ve from the power supply to the GND pin??

Emmanuel

2

Look at the 328 datasheet. ALWAYS do so. It specifies that voltage applied to any pin (except RESET) must be between -0.5V and Vcc+0.5V. Vcc is typically around 4.8-4.9V when powered over USB so yes, 5V is the maximum you should apply to analog pins (that gives a security margin).

If your board is powered correctly, yes, you can do what you describe, given that +Ve is not more than 5V from -Ve.

3

Connect a 10k resistor in series with the pin and you have some protection against mistakes. This limits the maximum current to a level the protection diodes can handle.

4

ok...thank you very much..will try your suggestions

5

But why would you connect the power supply to an analog input pin...... unless it's the voltage of the supply that's the subject of your measuring? Normally it's a signal from eg a temperature sensor like an LM35 that goes to the analog input, with 5V from (say) the Arduino output to the sensor's power in.