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Bushong - Chapter 6: Rectifiers, Transformers, Generators
Study Guide for Quiz
53
Medical
Not Applicable
10/23/2011

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Cards

Term
What is the purpose of the operating console?
Definition
To allow the tech to control the x-ray tube current (mA) and voltage (kVp)
Term
What are the 3 principle components of every x-ray imaging system?
Definition

1. x-ray tube

2. operating console

3. high voltage generator

Term
________ refers to the # of x-rays (intensity) expressed in milliroentgens (mR) or milliroentgens/milliampere - seconds (mR/mAs)
Definition
Quantity
Term
_______ refers to penetrability expressed as kilovoltage (kVp) or half value layer (HVL)
Definition
Quality
Term
Pick One: all the circuits connecting the meters and controls are at (low/high) voltages to minimize electrical shock hazard.
Definition
low
Term

Most x-ray machines operate at _____ V of power, however, some are at _____ V and

_____ V.

Definition
220, 110, 440
Term
______ ______: incorporates a meter to measure the voltage and a control to adjust the voltage to precisely 220 V.
Definition
Line Compensation
Term
________ is defined as an electrical device operating on the principle of mutual induction to change the magnitude of current and voltage.
Definition
a transformer
Term
A ______ (aka dynamo) converts mechanical energy to electrical energy by electromagnetic induction.
Definition
generator
Term
_______ _______: an electric current is induced in a circuit if some part of that circuit is in a changing magnetic field.
Definition
Electromagnetic Induction
Term
Faraday's Law: the magnitude of the induced current depends on four factors, they are:
Definition

1. The strength of the magnetic field

2. Velocity of the magnetic field as it moves past the conductor

3. Angle of the conductor to the magnetic field

4. Number of turns in the conductor

Term
_______: is a device that converts electrical energy to mechanical energy.
Definition
Motor
Term
A ______ uses mechanical energy like a hand crank, water, etc., to produce an electrical current. A ______ uses the electrical current to provide a mechanical motion.
Definition
Generator, Motor
Term
What type of current must a transformer have to operate?
Definition
AC (Alternating Current)
Term
True or False: a transformer establishes and provides the collapsing fields that induce the voltage changes in the secondary coil.
Definition
True
Term
True or False: transformers convert one form of energy to another.
Definition
False: it doesn't, it transforms electric potential and current into higher and lower intensity.
Term
The transformer is used to change the magnitude of voltage and current in an AC circuit. This change is ______ proportional to the ratio of the number of turns of the secondary coil to the number of turns of the primary coil.
Definition
directly
Term
Name the five types of transformers:
Definition

1. Air-core

2. Open Core

3. Closed Core

4. Shell-type

5. Autotransformer

Term
A transformer with a turns ratio greater than one is a step-____ transformer.
Definition
up
Term
A transformer with a turns ratio less than one is a step-____ transformer.
Definition
down
Term
What are the 3 main causes of transformer inefficiency?
Definition

1. Resistance: caused by copper wire

2. Hyperesis: additional resistance causing the alternating reversal of the magnetic field

3. Eddy Current

Term
________ is the process of changing AC current into DC current.
Definition
Rectification
Term
The tube requires current flow in how many directions?
Definition
One
Term
The _______ is the electronic device that keeps the current in the tube flowing in one direction only.
Definition
rectifier
Term
Rectification is accomplished by the _____.
Definition
diode
Term
_____: is an electronic device containing two electrodes.
Definition
the Diode
Term
What are the two types of diodes?
Definition

1. N-type

2. P-type

Term
What type of diode has loosely bound electrons that flow between conduction bands?
Definition
the N-type
Term
What type of diode has electron traps of + charged holes that attract and hold electrons?
Definition
the P-type
Term
______ ______ ______: the negative half of the current is supressed (below the line) emits x-rays only half the time.
Definition
Half Wave Rectification
Term
______ ______ ______: the negative half of the current is changed to positive and now lies above the line. Cuts exposure time in half.
Definition
Full Wave Rectification
Term
What are the types of generators? (name 6)
Definition

1. single phase

2. three phase (both 6  and 12 pulse)

3. capacitor discharge

4. battery operated

5. high frequency

6. falling-load

Term

What type of generator?

  • self-rectification, 1-2 diodes
  • suppresses inverse voltage
  • 120 pulses per second
  • improves heat loading of the x-ray tube
  • only uses half the power 
Definition
single phase
Term

What type of generator?

  • 3 pulse (waves)
  • potential difference never drops to zero
  • produces voltage ripple
  • 360 pulses/second (6 and 12 pulse also)
  • has three single phase currents out of step 120 degrees
Definition
three phase
Term
Name 3 advantages of a 3 phase generator:
Definition

1. high mA w/ short exposure

2. nearly constant potential

3. high effective kV

Term

What type of generator?

  • uses a capacitor (stores the charge)
  • works on DC current (stored charge)
  • Disadvantages: may continue to discharge after the usable exposure
Definition
capacitor discharge - used by mobile units
Term

What type of generator?

  • battery supplies DC to a rotary converter which changes to 3-phase 6 pulse AC
Definition
battery-operated
Term

What type of generator?

  • starts at a high mAs and then automatically adjusts down
  • have to be used with AEC or mAs control
  • disadvantage: wears out the filaments quicker
Definition
falling-load
Term

What type of generator:

  • starts with 3-phase power
  • charges a capacitor bank to DC
  • high frequency converter changes back to AC
  • the swissray room uses this type of generator
Definition
high-frequency
Term
Single phase power has a ___% voltage ripple in either half or full wave rectification.
Definition
100
Term
A three phase, six pulse has a voltage ripple of __%, meaning the voltage only "ripples" off maximum by __%
Definition
14
Term
A three phase, twelve pulse generator has a voltage ripple of __%
Definition
4
Term
A high frequency generator has a voltage ripple of less than __%.
Definition
1 - making it nearly constant
Term
Transformers and Generators usually are identified by their power rating in _______.
Definition
Kilowatts
Term

Current x Potential = Power

or

_______ x _______ = _______

Definition
Amperage, Voltage, Watts (or kW in most cases)
Term
For single phase generators you need a conversion factor of ___ due to its inefficiency.
Definition
0.7
Term
The operating console consists of what 5 things?
Definition

1. On/Off controls

2. kVp controls

3. mA controls

4. Time selector

5. AEC

Term
There are two ciruits in the x-ray machine, the _______ circuit and the _______ circuit aka as the _______ circuit.
Definition
Main, Secondary (Filament)
Term
The Main Circuit has a primary side (____ voltage) and a secondary side (____ voltage). 
Definition
low, high
Term
There are four major components of the timer circuit, they are:
Definition

1. exposure switch

2. mAs timer

3. electronic timers

4. AEC

Term
What is the turns ratio formula for voltage (also known as the "Autotransformer Law")?
Definition
Vs/Vp = Ns/Np
Term
What is the turns ratio formula for current?
Definition
Ip/Is = Ns/Np (current is inversely proportional)
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