Negative Temperature Coefficient resistors or NTC are devices having a characteristic as shown in the figure. The resistance decreases when the temperature rises.
Formula 1
Resistance of a NTC:
R = A x eB/T
Where:
R is the resistance in a given temperature in oK in ohm (Ω)
A is a constant given by the manufacturer of the NTC.
B is a constant given by the characteristic (range from 1,000 to 8,000 oK)
T is the ambient temperature in degrees Kelvin (oK)
Formula 2
Resistance of a NTC II:
Where:
R is the resistance in a given temperature in ohm (Ω)
Rto is the resistance at To in ohm (Ω)
e = 2.71828
T is the final temperature in degrees Kelvin (oK)
To is the reference temperature in degrees Kelvin (oK)
B is a constant given by the component characteristic
