I'm trying to understand how to test if a rotary encoder is operating correctly. I understand that there are 3 pins, A B C, and that as you rotate the encoder A and B will connect to C offset 90º. When nothing is connected, neither A or B read as connected C as I rotate the encoder. Does it only make this connection once voltage is present on A and B?
Also, when I connected 5v to either A or B through a 100k resistor, and connect C to ground, A and B continue to read 5v regardless of the encoder position. Is this a faulty encoder?