1.    Given the following information about temperature sensors, answer the questions listed below.

 

1. Negative Temperature Coefficient (NTC) thermistor

An NTC thermistor experiences such a large change in resistance per °C, small changes in temperature are reflected very fast and with high accuracy (0.05 to 1.5 °C). Because of its exponential nature, the output of an NTC thermistor requires linearization. The effective operating range is -50 to 250 °C for glass encapsulated thermistors or 150°C for standard.

2. Resistance Temperature Detector (RTD)

An RTD, consists of a film or, for greater accuracy, a wire wrapped around a ceramic or glass core. The most accurate RTDs are made using platinum but lower-cost RTDs can be made from nickel or copper. However, nickle and copper are not as stable or repeatable. Platinum RTDs offer a fairly linear output that is highly accurate (0.1 to 1 °C) across -200 to 600 °C. While providing the greatest accuracy, RTDs also tend to be the most expensive of temperature sensors.

3. Thermocouple

This temperature sensor type consists of two wires of different metals connected at two points. The varying voltage between these two points reflects proportional changes in temperature. Thermocouples are nonlinear, requiring conversion when used for temperature control and compensation, typically accomplished using a lookup table. Accuracy is low, from 0.5 °C to 5 °C. However, they operate from -200 °C to 1750 °C.

4. Semiconductor-based sensors

A semiconductor-based temperature sensor is placed on integrated circuits (ICs). These sensors are effectively two identical diodes with temperature-sensitive voltage vs current characteristics that can be used to monitor changes in temperature. They offer a linear response but have the lowest accuracy of the basic sensor types at 1 °C to 5 °C. They also have the slowest responsiveness (5 s to 60 s) across the narrowest temperature range (-70 °C to 150 °C).

Information from Ametherm Thermistors

You are designing a new pottery kiln for tribal pottery. The maximum temperature in the kiln will be 1500F degrees.

Which of the temperature sensors listed above should you use in the kiln?

 

 

  • Thermocouple 
  • RTD
  • Semiconductor-based
  • NTC

 

2.  You are designing an appliance that counts the number of animals that use a tunnel to cross under a highway. The highway is in the desert and when the temperature inside the appliance goes over 100F you want a fan to turn on and cool the device.

Using the same information on sensors listed above, which sensor would be a good choice for this design?

  • RTD
  • Semiconductor-based 
  • NTC
  • Thermocouple

 

3.  You are designing an industrial oven for a production line. The oven must heat parts to a very precise temperature range. This means the oven temperature must remain between 500F and 510F.

Using the same information on sensors listed above, which sensor would be a good choice for this design?

  • RTD 
  • NTC
  • Semiconductor-based
  • Thermocouple

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This is JAMD Bokhtier's website.He is a passionate Marketer who dreams,talks,learns and teaches all about Marketing,the owner & the founder of "Life Style Consultant", a specialist in "Digital Marketing" and a Sophophilic.

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