7. Generators & Charts

Question 1

With this type of unrectified power, multiple voltage wave forms are superimposed on one another, maintaining a nearly constant potential, and results in a waveform that exhibits 6 pulses per 1/60 second.

three-phase
DC
single-phase

Answer 1

three-phase

Question 2

Single-phase, full-wave rectification generators produce two pulses (2 half-cycles) of voltage per Hz. Knowing this, in one second with 60 Hz current there would be

120 pulses
150 pulses
160 pulses
130 pulses

Answer 2

120 pulses

Question 3

The voltage waveform that most closely resembles DC is created by which generator type?

Three-phase, twelve pulse
High-frequency
Single-phase, half-wave rectification
Three-phase, six-pulse

Answer 3

High-frequency

Question 4

According to Bushong, the voltage ripple associated with a three-phase, twelve-pulse generator is:

<1%
4%
100%
14%

Answer 4

4%

Question 5

A radiographic technique is being considered for a serial exposure examination (angiography). The parameters that will be used are: 400 mA @ 1/20 Sec., 85 kVp (HF, 180 Hz, 1.4 mm focus). The exposure rate will be 11 exposures a second for 4 seconds. The intended exposures for this study will:

1. produce 2,380 HU per exposure
2. produce 26,180 HU per second
3. result in a total of 225,000 HU

2 and 3 only
2 only
1 and 2 only
1 only

Answer 5

1 and 2 only

Question 6

What is the power rating for a 1Φ generator capable of delivering 150 kVp at 1,200 mA to the tube.

150 kW
252 kW
180 kW
126 kW

Answer 6

126 kW

Question 7

What makes singe-phase AC so inefficient when compared to DC is Single-phase AC voltage:

drops from peak to 0 twice per cycle
does not drop from peak to 0 twice per cycle
does not fluctuate
displays 0% voltage ripple

Answer 7

drops from peak to 0 twice per cycle

Question 8

The greatest radiation quantity and quality per exposure can be achieved with which generator type?

high-frequency (HF)
3Φ 12P
1Φ 2P
3Φ 6P

Answer 8

high-frequency (HF)

Question 9

Of the x-ray generators listed below, select the one that would generate the highest average photon energy per exposure if the kVp/mAs were kept exactly the same for each generator exposure.

Single-phase, half-wave rectified
Three-phase, twelve-pulse
High-frequency
Single-phase, full-wave rectified

Answer 9

High-frequency

Question 10

Recommendations for extending the x-ray tube life include all of the following except for:

do not make repeated exposures near tube loading limits
use higher mA stations when possible
warm up the anode to manufacturer’s recommendations
do not hold the rotor switch unnecessarily

Answer 10

use higher mA stations when possible

Question 11

Of the x-ray generators listed below, select the one that would generate the lowest exposure to the IR if the kVp/mAs was kept exactly the same for each generator exposure.

Three-phase, twelve-pulse
High-frequency
Single-phase, half-wave rectified
Single-phase, full-wave rectified

Answer 11

Single-phase, half-wave rectified

Question 12

This generator type produces a nearly constant potential voltage waveform, offering the best image quality at the lowest patient dose with the least amount of voltage ripple.

high-frequency (HF)
1Φ 1P
3Φ 6P
3Φ 12P

Answer 12

high-frequency (HF)

Question 13

Most commonly used with portable equipement, this x-ray generator type may exhibit leakage radiation after the desired exposure time has been reached.

single-phase, half-wave
capacitor discharge
high frequency
three-phase, six-pulse

Answer 13

capacitor discharge