The formula DF = PW x PRF is used to compute what property of pulsed emitters?

• A. Duty Factor
• B. Peak Power
• C. Average Power
• D. Exposure Duration

Answer: (A)

Duty factor is the fraction of time a pulsed emitter is on. The formula DF = PW x PRF captures that because PW is how long each pulse lasts and PRF is how many pulses occur each second. In one second, the device is emitting for PW seconds for every pulse, repeated PRF times, so the total on-time is PW x PRF seconds. Dividing by the one-second interval gives the fraction of time the device is active, i.e., the duty factor. If you want a percentage, multiply by 100. This ties directly to how much of the time the emitter is producing energy. Peak Power is the power during a pulse, not the time fraction; Average Power depends on the duty factor as Peak Power multiplied by DF; Exposure duration refers to how long exposure lasts, which isn’t determined by this formula alone.