Positive Temperature Coefficient resistors are components having a characteristic as shown in figure. Their resistance increases as the temperature rises.
Formula 1
Resistance:
Where:
α is the coefficient temperature above the reference temperature in degrees Celsius.
R1 and R2 are resistances in two different points of the characteristic
curve above the reference temperature in ohm (Ω)
Δt is the temperature difference between the considered points where
R1 and R2 are measured.
Note: characteristic curve are given by the PTC manufacturer and depends on each device.
