Duty cycle is defined as which of the following?

• A. The total time the device is delivering output
• B. The percentage of time the device is delivering output
• C. The maximum energy delivered per second
• D. The rate at which pulses are delivered

Answer: (B)

Duty cycle describes how much of a stimulation cycle the device is actively delivering current. It is the ratio of the on-time to the total cycle time, expressed as a percentage. For example, if the device is on for 2 seconds and off for 8 seconds, the cycle is 10 seconds long and the duty cycle is 20%. This matters because a higher duty cycle means more energy is delivered per cycle and more potential heating, while a lower duty cycle reduces energy and can feel more comfortable. The other descriptions refer to different aspects: the total time the device is on equals on-time (not a percentage), maximum energy per second involves both current and time and is not the duty cycle, and the rate of pulses describes pulse frequency, not the duty cycle.