Chapter 2, Problem 11PP

The pipe clip temperature sensors shown here are robust sensors that can be clipped directly onto copper pipes to measure the temperature of the liquids in the pipes.

Each sensor contains a device called a thermistor. Thermistors are semiconductor devices that exhibit a temperature-dependent resistance described by:

$R=R_0{e}^{\beta \left(\frac{1}{T}-\frac{1}{T_0}\right)}$

where R is the resistance (in Ω) at the temperature T (in °K), and R₀ is the resistance (in Ω) at the temperature T₀ (in °K). β is a constant that depends on the material used to make the thermistor. Thermistors are specified by providing values for R₀, T₀, and β.

The thermistors used to make the pipe clip temperature sensors have R₀ = 1075 Ω at T₀ = 85 °C, and β = 3969 °K. (Notice that β has units of °K. Recall that the temperature in °K is obtained by adding 273 to the temperature in °C.) The liquid temperature, in °C, is determined from the resistance R, in Ω, using

$T=\frac{\beta T_0}{T_0\ln \left(\frac{R}{R_0}\right)+\beta }-273$

Write a Java program that prompts the user for the thermistor resistance R and prints a message giving the liquid temperature in °C.