will conduct each switch will conduct 20μs in a 40μs cycle
over 3.334ms. For the next 3.334ms switches S1, S4 and S2,
S5 will conduct each switch will conduct 20μs in 40μs cycle
over 3.334ms. For the next 3.334ms switches S3, S6 and S2,
S5 will conduct each switch will conduct 20μs in 40μs cycle
over 3.334ms.