Analog Inputs reading voltage with nothing plugged in...

Not sure if I have a bad board.. First time using the board. tried connecting a few different sensors to the analog inputs. Was not getting the desired result. Opened the serial monitor and saw that the inputs always read about 5 volts, so I unplugged the jumpers from the board and even with nothing plugged into the analog inputs I'm reading between 1 and 2 volts.

Anybody have an idea if this may indicate a bad board? Using the Uno board.

Thanks, Scott

What you have is called a floating input: http://labjack.com/support/u3/users-guide/2.6.3.8

Generally you want to make sure that any analog pin you read from has connection to ground. Otherwise you can get random results (and in fact floating analog inputs are used to feed the random number generator).

Or you can use pull-up resistors if it is possible the pin won't be connected: http://wiki.openpicus.com/index.php?title=Read_from_Analog_Sensors

Thanks for the info.... Turns out the ground and voltage on my breadboard must be shorted together, a few of the senors I was trying to use did not work which led me to look at the raw readings of the input and was afraid the board was bad.

Scott