A switched mode power supply operating at $$20$$ $$kHz$$ to $$100$$ $$kHz$$ range uses as the main switching element

A triac can be triggered by a gate pulse of __________ polarity

The output voltage of a six - pulse double star rectifier is the same as that of a three - phase half wave rectifier

Match the following

List $$-$$ $${\rm I}$$
$$A.$$ Commutation
$$B.$$ $$V$$ $$-$$ Curves
$$C.$$ Free wheeling diode
$$D.$$ Overlap

List $$-$$ $${\rm II}$$
$$P.$$ Resistive load
$$Q.$$ Inductive load
$$R.$$ Capacitive load
$$S.$$ Inter pole
$$T.$$ Source Inductance
$$U.$$ Synchronous motor