What is the minimum value of the duty factor?

What is the minimum value of the duty factor?

• A. 10.0
• B. 1%
• C. 1.0
• D. 0.0%

Answer: (D)

The concept tested is how much of the ultrasound transmission time is used in one cycle, expressed as the duty factor. It’s the transmit duration divided by the total pulse repetition period, and it’s a dimensionless quantity that ranges from 0 to 1 (or 0% to 100% when expressed as a percentage). The smallest possible value is zero, which would mean the transducer is never emitting any pulse during a cycle. In theory, that’s the minimum. In practice there’s always some emission, but as a mathematical minimum it’s zero. The other options don’t fit as the minimum: a value of 1.0 would be 100% on-time (never off), and a value like 1% is a small but nonzero duty factor. A value of 10.0 would imply more than the full cycle’s time, which isn’t possible for a duty factor. So the minimum value is 0.0% (or 0 in ratio form).

The concept tested is how much of the ultrasound transmission time is used in one cycle, expressed as the duty factor. It’s the transmit duration divided by the total pulse repetition period, and it’s a dimensionless quantity that ranges from 0 to 1 (or 0% to 100% when expressed as a percentage).

The smallest possible value is zero, which would mean the transducer is never emitting any pulse during a cycle. In theory, that’s the minimum. In practice there’s always some emission, but as a mathematical minimum it’s zero. The other options don’t fit as the minimum: a value of 1.0 would be 100% on-time (never off), and a value like 1% is a small but nonzero duty factor. A value of 10.0 would imply more than the full cycle’s time, which isn’t possible for a duty factor.

So the minimum value is 0.0% (or 0 in ratio form).