Terms (2)

Question 1

What are the three Capabilities of a Transducer/Probe?

Answer 1

• Efficiency
• Sensitivity
• Resolution

Question 2

Efficiency

Answer 2

Piezoelectric ability for sending and receiving sound

• Transmission efficiency
• Reception efficiency
• Curie Temperature (°C)

Question 3

Sensitivity

Answer 3

Probes ability to detect a reflector.
- Certain size
- Certain depth
- Certain shape
- Certain material
Slight changes exist in all probes. Variance from manufacturers and construction process.

Question 4

Resolution

Answer 4

The ability to detect separate reflectors close together in space or time.
Three types:
- In-depth
- Near surface
- Far surface

Question 5

Piezoelectricity

Answer 5

When electrical charged the Crystal expands, when reversed it contracts. Used to generate vibrations to inspect the test specimen.

Question 6

Resonace

Answer 6

The natural Frequency that something vibrates at

Question 7

Bandwidth

Answer 7

When a crystal vibrates it produces a range of frequencies, Bandwidth is the range of frequency to which the crystal responds
- The range of frequencies from the lower frequency at 50% maximum (fl) to higher/maximum (fc) and back to 50% peak (fu)

Question 8

Mechanical/Q Factor

Answer 8

The time that the crystal rings following the initial pulse/energized.

Question 9

Dead Zone

Answer 9

The distance in material right below the transducer, reflectors in this zone cannot be seen because the crystal is still vibrating from the electric pulse

Question 10

Narrow and Broad Bandwidth Transducers

Answer 10

small Q factor = large bandwidth (broad) = more resolution = less sensitivity

Question 11

Baseline

Answer 11

Line in which the sound is displayed (horizontally)

Question 12

A-Scan

Answer 12

Displays returned signals (pips) from the specimen and any discontinuities.

Question 13

Initial Pulse (IP)/Main Bang

Answer 13

Large signal on the far left of the Digital display screen representing the electrical pulse sent to the transducer

Question 14

Echos

Answer 14

Secondary lines on a digital display that represent the sound bouncing back and being received by the crystal

Question 15

Horizontal axis on a digital display

Answer 15

represents time or distance

Question 16

Vertical axis on a digital display

Answer 16

represents how much sound is being reflected back to the transducer, more reflection, higher the pip

Question 17

pip

Answer 17

Signal (vertical) shown on an ultrasonic display

Question 18

Ghost Signals

Answer 18

When two sound pulse signals overlap each other instead of waiting for the first pulse to return before sending a second.

Question 19

6dB Drop Method

Answer 19

When an indication is to big and back wall reflection cannot be detected the 6dB Drop method is used.