18 Questions
What is the main component of an RTD?
A rod-shaped tube, often a length of fine coiled wire wrapped around a ceramic or glass core.
What is the typical material used to make an RTD element?
A pure material, often platinum, whose resistance at various temperatures has been documented.
Why is platinum well suited for industrial temperature measurement?
It is relatively immune to electrical noise.
What is the significance of the '100' in Pt100?
It represents the resistance of 100Ω at 0°C.
What is the purpose of the thermowell in an RTD?
To house the RTD element and protect it from damage.
What is the predictable change in an RTD element that is used to determine temperature?
A change in resistance as the temperature changes.
What type of material is a thermistor, and how does its resistance change with an increase in temperature?
A thermistor is a type of semiconductor, and its resistance decreases as temperature increases.
What is the difference between NTC and PTC thermistors?
NTC (negative temperature coefficient) thermistors have a decreasing resistance with increasing temperature, while PTC (positive temperature coefficient) thermistors have an increasing resistance with increasing temperature.
How does the resistance of an NTC thermistor change with temperature?
The resistance of an NTC thermistor increases in a non-linear fashion with decreasing temperature.
What type of applications typically use lower resistance thermistors (2252 to 10,000Ω)?
Low-temperature applications (-55 to approx. 70°C) typically use lower resistance thermistors.
What is the primary use of PTC thermistors?
PTC thermistors are often used for circuit protection.
What is the term used to describe a thermistor, based on its characteristics?
A thermistor is often referred to as a 'thermally sensitive resistor'.
What is a major difference between thin-film RTD elements and wire-wound RTD elements?
Thin-film elements are more resistant to damage from shock or vibration.
What is the benefit of using wire-wound RTDs with ceramic cores?
They can accurately measure extremely high temperatures.
What are the RTD accuracy classes, and what is the temperature range they can measure?
The accuracy classes are B, A, AA, and they can measure temperatures from -196 to 600 °C.
Why are wire-wound RTDs more expensive to manufacture than thin-film RTDs?
They require skilled labor and advanced assembly facilities.
What happens when an RTD operates outside its range?
Possible damage may occur, which affects the accuracy of the reading.
Why is an output amplifier necessary for RTDs?
To amplify the output for proper reading.
Learn about thermistors, their properties, and their applications in temperature measurements. Understand how thermistors work and their relationship with temperature.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
