MULTIPLE CHOICE QUESTIONS WITH ANSWERS ON WIRELESS SENSOR NETWORKS
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MULTIPLE CHOICE QUESTIONS WITH ANSWERS ON POWER ELECTRONICS AND DRIVES
[Q-1] Silicon based rectifiers are preferred than germanium based rectifiers because (a) Si is available easily compared to Ge (b) Only Si has a stable off state (c) Ge is very temperature sensitive (d) Si only has the characteristics 1 ! " # 1 at lo$ collector currents and reaches 1 at high currents %hich of the above above statements statements are true& Options' 1 * +* , " +* , + Only . , Only / 0one of the above options Answer: 2
[Q-"] n a triac* (a) 2he triggering pulse to main terminal 1 should be of the same polarity as the anode potential bet$een 321 and 32" (b) 2he triggering pulse should be of opposite polarity to that of anode potential (c) %hen the triggering pulse is positive and anode is positive* it is operating in the first 4uadrant (d) %hen the triggering pulse is negative and anode is negative its sensitivity is highest %hich of the above above statements statements are true& Options' 1 * , " * 5 5* , . * 5* , / 0one of the above options Answer: 4
[Q-] n a single phase full $ave S56 circuit $ith 6* 7 load
(a) 8o$er is delivered to the source for firing angle of less than 9:; (b) 2he scr changes from inverter to converter at < 9:; (c) 2he negative dc voltage is ma=imum at < 1>:; (d) 2o turn off the scr* the ma=imum delay angle must be less than 1>:; %hich of the above statements are true& Options' 1 5* , " 5 Only , Only . * + / 0one of the above options Answer: 1
[Q-.] %hile comparing triac and scr* (a) +oth are unidirectional devices (b) 2riac re4uires more current for turn on than scr at a particular voltages (c) triac has less time for turn off than S56 (d) +oth are available $ith comparable voltage and current ratings %hich of the above statements are true& Options' 1 * 5 " +* 5 * + . , Only / 0one of the above options Answer: 2
[Q-/] %hich of the follo$ing statements are true (a) f the S56* even $ith proper gate e=citation and anode-cathode voltage does not conduct for a particular load resistance* then it $ould be necessary to decrease the load resistance to turn O0 the S56 (b) 2he S56 $ould be turned O?? by voltage reversal of the applied anode-cathode ac supply of fre4uencies up to :@AB (c) f the gate current of the S56 is increased* then the for$ard brea@do$n voltage $ill decrease Options
[Q-C] %hich of the follo$ing statements are true %hen gate triggering is employed* a S56 can $ithstand higher values of diDdt* if the 1 Gate current is increased " 6ate of rise of gate current is increased Gate current is increased . 6ate of rise of gate current is decreased O82O0S' (a) * . (b) 1* . (c) "* (d) 1* " (e) 0one of the above options Answer: A
[Q-E] n a S56 based converter* the free $heeling diode is used to (a) dd to the conduction current of thyristors (b) Oppose the S56 conduction (c) 5onduct current during the O?? period of the S56 (d) 8rotect the S56 by providing a shunt path Answer: C
