Chapter 21 Semi conductor Input devices

Question 1

thermistor

Answer 1

temperature-sensitive resistor whose
resistance changes with a change in temperature.

Question 2

______ ______thermistors are used in voltage regulators,
vacuum gauges, and electronic time-delay circuits.

Answer 2

Directly heated

Question 3

________ ______ thermistors are used for precision temperature
measurement and temperature compensation.

Answer 3

Indirectly heated

Question 4

device that condcuts current when enrgized by light

Answer 4

Photo condcutive cell (photo cell)

Question 5

photo condcutive diode

Answer 5

switched on and off by light

Question 6

pressure sensor

Answer 6

transducer that outpouts a voltage or current with corresponding change in pressure

Question 7

flow detection sensor

Answer 7

detects the movement of liquid (flow) or gas using solid state device

Question 8

Hall effect sensor

Answer 8

detects the prox of magnetic field

Question 9

hall generator

Answer 9

thin strip of semicondcutor material which a constant control current is passed

Question 10

Proximity sensor (prox switch)

Answer 10

solid state sensor that detects the presence of an object by means of an electric sensing field

Question 11

Indcutive proximity sensor

Answer 11

detects only conductive substances ( only detect metals)

Question 12

capacitive proximity sensors

Answer 12

detects either condcutive or nonconductive substances

Question 13

________ _______ _______operate on eddy current killed (ECKO) principle

Answer 13

Indcutive proximity sensor

Question 14

________ _______ have a relatively high dialectric constant of 1.2 or greater

Answer 14

Dialectric Constant

Question 15

ultrasonic sensor

Answer 15

detects the presence of an object from high frequency sound waves (200kHz)

Question 16

ultra sonic operator modes

Answer 16

Direct mode
Diffused mode

Question 17

Direct mode for ultrasonic sensor

Answer 17

emitter and reciever placed opposite of each other so that the sound waves from the emitter are recived from reciever

Question 18

Diffused mode for ultra sonic sensor

Answer 18

sends out sound wave and reciver listens for sound wave echo biouncing back off an object