When voltage feedback (negative) is applied to an amplifier, its input impedance ___________
A). Is decreased
B). Is increased
C). Remains the same
D). None of the above
Negative feedback is employed in ___________
A). Oscillators
B). Rectifiers
C). Amplifiers
D). None of the above
A synchronous motor can be made self starting by providing
A). Damper winding on rotor poles
B). Damper winding on stator
C). Damper winding on stator as well as rotor poles
D). None of the above
When load on an over-excited or under excited synchronous motor is increased, rate of change of its armature current as compared with that of power factor is
A). more
B). less
C). equal
D). twice
The ratio of starting torque to running torque in a synchronous motor is
A). zero
B). one
C). two
D). infinity