231. For power output higher than 15 kW, the suitable rectifier is________________?
A. Single phase
B. 3 phase
C. Poly phase
D. Only (b) and (c)
232. In current commutated DC-DC choppers, the voltage spike appears across the load when_____________?
A. Voltage across the commutating inductances collapses
B. The capacitance voltage adds to the supply voltage
C. Both A. and B.
D. None of these
233. The sum of all phase current in a star connected primary winding with no neutral connection is equal to___________?
A. Phase current
B. Three times the phase current
C. Three times the line current
D. Zero at all times
234. In a load commutated DC – DC chopper, the capacitor has a_____________?
A. Symmetric triangular voltage across itself
B. Symmetric rectangular voltage across itself
C. Symmetric trapezoidal voltage across itself
D. Symmetric sinusoidal voltage across itself
235. In a 3 phase bridge rectifier the ripple frequency is _____________?
A. Equal to the input frequency
B. Twice the input frequency
C. Three times the input frequency
D. Six times the input frequency
236. Voltage commutation circuit can be converted into a current commutation by interchanging the positions of____________?
A. Diode and capacitor
B. Capacitor and SCR
C. Inductor and capacitor
D. Capacitor and load
237. DIAC are specifically designed to trigger______________?
A. TRIAC
B. SCR
C. GTO
D. Only (a) and (b)
238. For swept frequency measurements, the input impedance of the mismatched transmission line would vary with frequency as the electrical length of the transmission line would
A. Decrease with frequency
B. Remains same with change in frequency
C. Increase with frequency
D. Either A. or B.
239. As the breakdown voltage reached, the DIAC exhibits?
A. Negative resistance characteristics
B. Goes into avalanche condition
C. Voltage drop snaps back
D. All of these
240. In EMC signal, the source delivers maximum power to the input of transmission line when the transmission line input impedance
A. Is equal to the source resistance
B. Greater than the source resistance
C. Smaller than the source resistance
D. None of these
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