Hello, I'm trying to build a temp sensor with a thermistor available in the workshop kit (a 4k7 thermistor), and I'm getting a strange behavior: the resistance seems to decrease with temperature!
my circuit is very simple:
I'm measuring Vx at the "x" with analog pin 0, between the thermistor and the 10k resistor. What I get is: if I increase the temperature, the adc (and Vx) is increasing. => Rx (the resistence of the thermistor) is decreasing, according to: Rx = R*(V - Vx)/Vx (where V=5v and R=10kohm)
I've tested the circuit replacing the thermistor with resistors of known values plugged into 5v, and the behaviour is correct: the bigger the resistor, the lower is the voltage measured at "x".
Any suggestions? What am I getting wrong???