#### Electrical engineering

• ( 2 ) Present day HVDC converters are all

• 1) 3 pulse converters
• 2) 6 pulse converters
• 3) 12 pulse converters
• 4) either 6 pulse or 12 converters
• Discussion in forum
Answer : 3) 12 pulse converters
Solution : Present day HVDC converters are all 12 pulse converters

discussion

Answer : 3) 12 pulse converters

• ( 3 ) In dielectric heating, the thyristor circuits consist of

• 1) rectifier-chopper combination
• 2) controlled rectifier
• 3) ac regulator
• 4) rectifier-inverter combination
• Discussion in forum
Solution : In dielectric heating, the thyristor circuits consist of rectifier-inverter combination

discussion

• ( 4 ) In a semi converter feeding a resistive load, the firing angle is a. Each thyristor conducts for

• 2) (p - a) radians
• 3) (p + a) radians
• 4) (p - 0.5 a) radians
• Discussion in forum
Solution : In a semi converter feeding a resistive load, the firing angle is a. Each thyristor conducts for (p - a) radians

discussion

• ( 5 ) In controlled heating circuits, thyristors act as

• 1) rectifier
• 2) inverter
• 3) ac regulato
• 4) chopper
• Discussion in forum
Solution : In controlled heating circuits, thyristors act as ac regulato

discussion

• ( 6 ) A relaxation oscillator uses

• 1) tunnel diode
• 2) UJT
• 3) both tunnel diode and UJT
• 4) PIN diode
• Discussion in forum
Solution : A relaxation oscillator uses UJT

discussion

• ( 7 ) A single phase full converter can operate in

• Discussion in forum
Solution : A single phase full converter can operate in 2 quadrants

discussion

• ( 8 ) The gate lead, in a thyristor is welded to :

• 1) p layer to which anode is connected
• 2) n layer nearest to the anode terminal
• 3) p layer nearest to the cathode terminal
• 4) outside n layer
• Discussion in forum
Answer : 2) n layer nearest to the anode terminal
Solution : The gate lead, in a thyristor is welded to n layer nearest to the anode terminal

discussion

Answer : 2) n layer nearest to the anode terminal

• ( 9 ) The characteristics of which device has peak point and valley point

• 1) SCR
• 2) PUT
• 3) SCS
• 4) Shockley diode
• Discussion in forum
Solution : PUT

discussion

• ( 10 ) Thyristors connected in series need :

• 1) static equalizing circuit
• 2) dynamic equalizing circuit
• 3) both static and dynamic equalizing circuits
• 4) None of these
• Discussion in forum
Answer : 3) both static and dynamic equalizing circuits
Solution : Thyristors connected in series need static and dynamic equalizing circuits

discussion

Answer : 3) both static and dynamic equalizing circuits