Question

Which of the following is NOT true about thermistor and resistance temperature detectors?
1. Thermistors are more accurate and cheaper than RTDs.
2. Thermistors have faster response time than RTDs. 
3. Thermistors can measure temperature over a wider range than RTDs 
4. Thermistors are commonly made with ceramic or polymer materials while RTDs are made of pure metals

Answer 1

Correct Answer - Option 3 : Thermistors can measure temperature over a wider range than RTDs 

Comparison between RTD's and thermistor are as follows:

Range:

1) Thermistors can only track a narrow temperature range. They can only measure up to 130°C

2) While some RTDs can exceed 600°C

Sensitivity:

1) Thermistors have a sensitivity of around 10 Ω/°C

2) While RTD sensors change resistance <<0 Ω/°C 

3) Therefore Thermistors are faster than RTD's

Accuracy:

1) Thermistors due to their high sensitivity are more accurate.

2) RTD's are comparatively less accurate than Thermistors.

Material:

1) Thermistors are made of semiconductors, ceramic, polymer material, etc.

2) RTD's are made of platinum, nickel, copper, etc.

Applications:

1) Thermistors are widely used in home appliances.

2) RTD's are used for industrial purposes.

Cost:

1) Are comparatively inexpensive than RTD's.

2) Thermistors with a wider temperature range are often more costly than RTDs.

3) Temperature changes cause predictable resistance changes in both thermistors and RTDs.