Answer / guna

Commutator function is to deliver the dc supply at the
output terminals, it only happens when there is a
rotating part on the equipment cause it reverses the emf
when there is an alternate south and north pole crosses
at the mid point of plane. The collection of current only
possible when there is a carbon or copper brushes
attached on the surface. So We cant see the whole setup
in power electronic devices, And more over that, the main
objective of power electronic devices is to operate at
higher current and voltage levels within compact sizes
(tiny size), for reliability. Due to rotational parts
losses also increases & wiring cost & insulation
required. Commutator can't terminate the ripples or
disturbances in the output supply but power electronic
equipment's can do. So power electronic devices more
sophisticated than commutator.

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