test 5

Question 1

Sensors which use an NPN transistor to switch the output circuit are _____

Answer 1

current sinking

Question 2

which sensor uses a resistance reading in ohms to get a temperature measurement

Answer 2

thermistor

Question 3

in most instances _______ systems are considered to be automatic control while ______ systems provide manual control

Answer 3

closed loop / open loop

Question 4

a device constructed of 2 dissimilar metals that generate a small current when one end is heated

Answer 4

thermocouple

Question 5

A _______ photoelectric control is a photoelectric control the energizes the output switch when the target is missing.

Answer 5

light operated

Question 6

not a type of proximity sensor

Answer 6

photoelectric

Question 7

______ scan is a scanning technique which uses a special lens to filter the emitter’s beam of light so that it is projected in one plane only.

Answer 7

polarized

Question 8

_______ scan is a scanning technique which places the transmitter and receiver at equal angles from a highly reflective surface.

Answer 8

specular

Question 9

flow detection sensor operates on the principle of ______

Answer 9

thermal conductivity

Question 10

with a ____ thermistor an increase in temperature will cause the resistance of the thermistor to increase

Answer 10

PTC

Question 11

ac photoelectric sensors are connected in _____ with the load to be controlled

Answer 11

series

Question 12

which lead controls or triggers an SCR to conduct

Answer 12

gate

Question 13

2 reasons for photocell failure

Answer 13

humidity / contamination

Question 14

7 factors that determine the best scanning technique

Answer 14

1. scanning distance
2. size of target
3. reflectance level
4. target positioning
5. differences in color and reflective properties between background and target
6. changes in ambient light intensity
7. condition of the surrounding air

Question 15

sensor that is a proximity switch the detects conductive substance

Answer 15

inductive

Question 16

sensor is a proximity switch that detects a magnetic field

Answer 16

hall effect

Question 17

3 advantages of an operational amplifier

Answer 17

high gain
low gain
low output impedance

Question 18

4 types of hall effect sensor activation

Answer 18

head on 
slide by
vane
pendulum
rotary
electromagnetic
prox shunt