Measuring electricity 389 Nonlinear load profile, comprised of A+B+C A. 60 HERTZ FUNDAMENTAL B. 180 HERTZ 3RD HARMONIC C. 300 HERTZ 5TH HARMONIC ONE CYCLE (1/60TH SECOND) FIGURE 14.4 Nonlinear loads produce distortions on the current waveform that are the summation of first-, third-, and fifth-order (and higher) harmonics.