An aircraft electrical system operates at 115 volts at 400 hertz. It is to supply an average d.c. voltage of 28 volts and an average current of 20 A at a ripple factor of 0.005. Determine: The r.m.s. ripple voltage Here is my attempt. Vc= Vs-2Vd =28-2(0.7) = 26.6 Volts Vr= (1/2 x fs x C x Rl )(Vc) R=V/I 28/20= 1.4 (1/2x400x1.4)(26.6) = 0.023 Vrms= Vr/2sqrt3 Vrms = 0.0063 Now theres a good chance I'm way of here.....Thanks for any help!