Question

A device 'X' is connected to an ac source V = $V_{0} sin \omega t$. The variation of voltage, current and power in one cycle is shown in the following graph.
(a) Identify the device 'X'.
(b) Which of the curves A, B and C represent the voltage, current and the power consumed in the circuit?

Answer 1

To keep the torque on DC  motor  from reversing  every time the coil moves through the plane perpendicular to the magnetic field a split ring device called a  commutator is used to reverse the current at that point the purpose of the split ring commutator in a DC  Motor is A)to prevent the battery or power sup