Deck 17: Temperature Sensing Devices

Question 1

When two dissimilar metals are joined at one end, and that junction is heated, a voltage is produced. This is known as the ____________________ .

Answer 1

Seebeck effect

Question 2

A very common device that uses the principle of expanding metal to operate a set of contacts is the ____________________ relay found in the refrigeration industry.

Answer 2

hot-wire starting

Question 3

A thermistor that has a positive temperature coefficient will decrease its resistance as the temperature increases.

Answer 3

False

Question 4

The amount of voltage produced by a thermocouple is determined by what two things?

Question 5

Describe a bimetal strip.

Question 6

Figure 17-11


The accompanying figure is showing a(n) ____________________.

Question 7

Because of their nonlinear characteristics, thermistors are often used as set point detectors as opposed to actual temperature measurement.

Question 8

When a metal bar is mechanically held at one end, it permits the amount of expansion to be in one direction.

Question 9

Thermocouples produce high voltages.

Question 10

Metal expands when heated. The amount of expansion is proportional to what two factors?

Question 11

Why must electrical contacts never be permitted to open or close too slowly?

Question 12

A common method of sensing a change of temperature is by the increase of pressure of some chemicals.

Question 13

Name the two different types of thermistors.

Question 14

The ____________________ is the most common heat sensing device used in the production of room thermostats and thermometers.

Question 15

The resistance temperature detector (RTD) is made of ____________________ wire.