Stimulus frequency (rate) is defined as:

• A. The frequency in cycles per second or Hz
• B. The momentary intensity of the pulse
• C. The total on-time per treatment
• D. The time between on and off states

Answer: (A)

Stimulus frequency describes how often the electrical pulses are delivered per second. It’s the rate at which pulses occur, measured in cycles per second, or Hz. If five pulses happen each second, the frequency is 5 Hz. One cycle includes the pulse being on (on-time) and the interval with no current (off-time); the frequency is the inverse of the total time for one cycle (period). The other terms describe different aspects: the momentary intensity is the amplitude of each pulse, the total on-time per treatment is how long current is delivered overall, and the time between on and off states is the off-time within a cycle.