X-ray circuits

Question 1

electrostatics

Answer 1

study of stationary electric charges

Question 2

how are electrical charges measured

Answer 2

in SI unit coulombs

Question 3

which is free to move and which is fixed
protons and electrons

Answer 3

free to move - electrons
fixed - protons

Question 4

what do good conductors have

Answer 4

a larger number of free electrons

Question 5

what do good insulators have

Answer 5

few free electrons

Question 6

like charges

Answer 6

repel

Question 7

opposite charges

Answer 7

attract

Question 8

electrodynamics

Answer 8

movement of electrons

Question 9

what is electric potential

Answer 9

the ability to do work because of separation of charges

Question 10

what is needed to move electrons

Answer 10

electrical potential

Question 11

what are charges like in x-ray tube

Answer 11

separated
anode - positive
cathode - negative

Question 12

what does electricity result from

Answer 12

movement of electrons

Question 13

electric potential unit

Answer 13

volt

Question 14

current unit

Answer 14

ampere

Question 15

what is current

Answer 15

flow of electrons

Question 16

what is 1 coulomb

Answer 16

amount of charge that flows in 1 second if there is a current of 1 ampere

Question 17

what is a volt

Answer 17

ratio of joules to coulombs
(volt = joules/coulombs)

Question 18

what is resistance

Answer 18

impedes the flow of electricity

Question 19

resistance unit

Answer 19

ohm

Question 20

what do the lines in the electric field show

Answer 20

the direction in which an isolated positive charge would move if placed at any point in the field

Question 21

how is the strength of electric field shown

Answer 21

by how close the lines are together

Question 22

where does the electric field extend

Answer 22

in 3 dimensions

Question 23

what is the electric field associated with

Answer 23

two parallel charged plates called electrodes

Question 24

negative electrode

Answer 24

cathode

Question 25

positive electrode

Answer 25

anode

Question 26

what is the direction of the electric field

Answer 26

from positive to negative

Question 27

what happens as potential difference increases

Answer 27

electron moves towards the anode gaining more KE

Question 28

kV

Answer 28

the voltage across the x-ray tube the potential difference that drives electrons across the x-ray tube

Question 29

mA

Answer 29

the values of the electric current formed by the flow of electrons across the x-ray tube

Question 30

s

Answer 30

the x-ray exposure duration the total time for which the electrons flow through the x-ray tube

Question 31

mAs

Answer 31

the product of mA and s

Question 32

why do electrons travel between cathode and anode

Answer 32

due to potential difference

Question 33

what does current control

Answer 33

number of electrons and hence number of x-rays emitted

Question 34

what does voltage control

Answer 34

the KE gained by electrons before it strikes the anode

Question 35

what is KE used to do

Answer 35

produce x-rays

Question 36

functions of x-ray circuit

Answer 36

maintains a steady voltage across the tube convert mains supply from AC to DC provide current to heat the filament accurately control exposure duration provide power to drive the induction motor

Question 37

what does primary circuit consist of

Answer 37

main power switch circuit breakers autotransformer timer circuit primary side of step-up transformer

Question 38

what does secondary circuit consist of

Answer 38

secondary side of step-up transformer mA meter rectifier bank x-ray tube (except for filaments)

Question 39

what does filament circuit consist of

Answer 39

consists of: a rheostat step down transformer the filaments

Question 40

what does it look like when exposure switch is open and closed

Answer 40

open - line not connecting to circuit closed - line connecting circuit

Question 41

what controls the transformers

Answer 41

selecting kVp at the console

Question 42

what is transformer dividing line between

Answer 42

primary and secondary circuits - primary coil is in primary circuit - secondary coil is in secondary circuit

Question 43

why is exposure timer needed

Answer 43

to deliver exposure for correct time

Question 44

what is exposure timer based on

Answer 44

charge of capacitor

Question 45

what current is needed for transformers to operate correctly

Answer 45

AC

Question 46

within x-ray tube where must current always flow

Answer 46

current = from anode to cathode electrons = from cathode to anode x-ray tube exposed to AC would be disastrous

Question 47

rectifiers

Answer 47

in secondary circuit one way valves for electricity

Question 48

why are rectifiers needed

Answer 48

to convert AC to DC

Question 49

purpose of filament circuit

Answer 49

control degree and duration that the filament is heated in turn this controls the number of electrons boiled off that will ultimately become the tube current

Question 50

rheostat

Answer 50

in filament circuit variable resistor controlled by the mA selector on the console

Question 51

what does exposure timer in secondary circuit work in concert with

Answer 51

the rheostat in filament circuit

Question 52

what do rheostat and exposure timer determine

Answer 52

quantity of electrons boiled off of the filament and available for x-ray production

Question 53

the kVp selected adjusts the.. and determines...

Answer 53

autotransformer determines number of turns on secondary side necessary to produce a voltage that will be sent to the step-up transformer

Question 54

what happens after electricity passes through the rectifiers

Answer 54

electricity creates a large positive charge on the anode and a large negative charge on cathode focusing cup

Question 55

autotransformer

Answer 55

in primary circuit adjustable transformer

Question 56

what does autotransformer determine

Answer 56

number of turns on the secondary slide

Question 57

main power switch

Answer 57

in primary circuit on/off switch for unit, connected to facility's power supply

Question 58

circuit breaker

Answer 58

in primary circuit protect against short circuit and electric shocks

Question 59

timer circuit

Answer 59

in primary circuit ensures exposure doesn't exceed predetermined time

Question 60

primary side of step up transformer

Answer 60

in primary circuit increases voltage from autotransformer to kV needed for x-ray production

Question 61

mA meter

Answer 61

placed in secondary circuit monitors x-ray tube current

Question 62

secondary side of step up transformer

Answer 62

in secondary circuit increases voltage from autotransformer to kV needed for x-ray production