High Voltage Generator (Part 2) Flashcards Preview

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Flashcards in High Voltage Generator (Part 2) Deck (75):
1

Limits current from power line to generator

Circuit breaker

2

Allows generator to be DISCONNECTED from power line

Circuit Breaker

3

Used to change incoming power to needed levels

High Voltage Section/Generator

4

Responsible for increasing the output voltage

High Voltage Section/Generator

5

Used for ELECTRICAL INSULATION

Oil

6

The secondary voltage is higher than the primary voltage

Step up transformer

7

Generator operates only on ___

Alternating current

8

In HVS the voltage waveform is

Sinusoidal

9

Only difference bet primary and secondary waveforms

Amplitude

10

Primary voltage is measured in

Volts

11

Secondary voltage is measured in

kilovolt peak (kVp)

12

Primary current is measured in

Amperes

13

Secondary current is measured in

milliamperes

14

Derived from a cell or a battery

Direct current

15

The positive and negative terminals are fixed

Direct current

16

No fixed terminal

Alternating current

17

X-ray tube must be provided with

Direct current

18

X-rays are produced by _____ from cathode to anode

Acceleration of electrons

19

X-rays cannot be produced by electrons flowing in the ____

Reverse direction (anode to cathode)

20

Process of AC is converted into DC

Rectification

21

Ensure electron flow in one direction (cathode to anode)

Rectification

22

Electronic device that allows current flow in only one direction

Rectifier

23

A device that performs the opposite function (DC to AC)

Inverter

24

Electronic device that contains two electrodes

Diode

25

Conductor through which electric current is passed

Electrode

26

Electrode may be

Wires
Plates
Rods

27

Made of silicon

Solid state rectifiers

28

Have the ability to conduct electricity

Semiconductors

29

Have loosely bound electrons

n-type

30

Spaces (holes), no electrons

p-type

31

If higher potential is placed in the p-side of the junction,

Electrons and holes will migrate towards the junction

32

Flow of electrons and holes constitutes an _____

Electric current

33

If positive potential is placed on the n-side,

Electrons and holes will be swept away from the junction

34

No flow of electrons

No electric current

35

Unrectified voltage

Alternating current

36

In unrectified voltage, the current that passes through the X-ray tube during

Positive half cycle

37

During the negative half of the cycle

Current can flow only from anode to cathode

38

Not constructed I emit electrons

Anode

39

Simplest type of rectifier

Half wave rectifier

40

Uses one diode

Half wave rectifier

41

During the positive portion (half wave)

Allows electric current to pass through the X-ray tube

42

Negative portion (half wave)

No electric current

43

Problems of half wave rectification

Wastes half of the electric power supply
Twice the exposure time

44

Consists of atleast four diodes

Full wave rectification

45

Four rectifiers are arranged in

Bridge rectifier

46

The negative half-cycle (full wave) corresponds to

Inverse voltage is reverse

47

In full wave rectification

Anode is always positive

48

No gaps in the output waveform

Full wave rectification

49

All of the input waveform is converted to

Usable output

50

Pulsed X-ray output of a full wave rectified machine occurs

120 times each second

51

Another way to characterized the voltage waveform

Voltage ripple

52

Percentage of maximum kV

Voltage ripple

53

Less voltage ripple =

Greater radiation quantity and quality

54

Length of time in seconds that the waveform takes to repeat itself

Period

55

Waveform for sine waves

Periodic time

56

Waveform for square waves

Pulse width

57

Number of times that the waveform repeats itself

Frequency

58

Reciprocal of the time period

f = 1/T

59

Unit of frequency

Hertz

60

Magnitude or intensity of the signal waveform

Amplitude

61

Amplitude is measured in

Volts or amps

62

Voltage waveforms are produced by

single-phase electric power

63

SPP results in a

Pulsating X-ray beam

64

Single phase input power results in

Pulsed radiation

65

X-rays produced with SPP has a value near zero

Little value because of lower energy

66

Disadvantages of pulsed radiation

Only significant when voltage is near peak
Produce low-energy photons (contribute to dose)

67

Multiple voltage waveforms are superimposed on one another

Three-Phase Power

68

All three wires :

Carry the same current
Constantly balanced power load

69

Usually operates at 500 to 25,000 Hz

High frequency generator

70

Uses inverter circuits

High frequency voltage generator

71

Inverter circuits which are high speed switches converts

DC into a series of square pulse

72

Much smaller than 60Hz high voltage generator

High frequency generator

73

Produces a near constant potential voltage waveform

High frequency generator

74

Measured in kilowatts (kW)

Power

75

Generator connected to power line through a _____

Circuit breaker