64351. A thyristor has a turn on time of 6 μs. If the anode circuit is inductive, the turn on time will be
64352. The total number of leads in reverse conducting thyristor is
64353. Assertion (A): A TRIAC is a bidirectional SCR.Reason (R): A TRIAC is a four layers 3 terminal device and can conduct in both directions.
64354. If Vdc1 is the dc output voltage in half wave controlled rectifier circuit feeding resistive load and Vdc2 is the dc output voltage in full wave controlled rectifier circuit (M - 2 connection) feeding resistive load, then
64355. A semi converter operates in two quadrants.
64356. Figure shows a chopper feeding RLE load, The free wheeling diode conducts when
64357. Assertion (A): An ideal rectifier should have unity harmonic factorReason (R): An ideal rectifier should have unity displacement factor.
64358. A single phase half wave rectifier is feeding a resistive load. When a = 0, dc output voltage is 127 V. When a = 30°, the dc output voltage will be about
64359. A dc circuit breaker must use
64360. In a single phase full wave regulator feeding R-L load, the minimum firing angle can be zero.
64361. An RC snubber circuit is used to protect a thyristor against :
64362. A DIAC has two terminals, anode and cathode.
64363. A single phase semiconverter has a freewheeling diode. If the firing angle is a and the load is purely resistive, the periods of conduction and freewheeling respectively are
64364. A dc separately excited motor has a constant field current. The armature is fed from a single phase supply through a semi-converter. When a = 0, speed is 600 rpm. If a = 90°, the speed is likely to be
64365. A static induction thyristor
64366. A single phase step up cycloconverter changes 50 Hz to 100 Hz. Then one half wave of input will give rise to
64367. Which of these triggering methods for series connected SCRs use LASCR in the gate circuit?
64368. A 3 phase ac regulator uses
64369. The average load current supplied by a thyristor depends on
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64371. In a 3 phase full wave regulator feeding a star connected resistance load the input voltage is 400 V line to line. The firing angle is 160°. The line to line output voltage would be
64372. A thyristor is reverse biased. A positive gate pulse is applied. The thyristor
64373. A single phase series converter is used for
64374. A single phase half wave controlled rectifier circuit has an R-L load. A freewheeling diode is also in the circuit. When freewheeling diode is conducting the SCR
64375. An SBS can conduct is one direction only.
64376. A 750 A circuit uses thyristor of current rating 175 A. If derating is 25%, the number of thyristors in parallel is
64377. Assertion (A): An inverter does not require forced commutation Reason (R): A series inverter is a forced commutation inverter.
64378. In a single phase full wave converter (M - 2 connection), the rms transformer voltage is 300 V across each half of secondary. The PIV for each thyristor is
64379. The number of doped regions in a SCR is
64380. All inverters use forced commutation.
64381. In 180° mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time.
64382. In a single phase full wave ac regulator the rms value of load current is 20 A load is purely resistive. Then
64383. A reactor is used in a dual converter operating in non-circulating current mode.
64384. Which of these commutation methods uses an auxiliary SCR?
64385. A thyristor needs protection against
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64387. In integral cycle control the period of on-off control should be more than mechanical time constant of load.
64388. A single phase half wave converter is feeding a resistive load. Just before triggering, the voltage across thyristor is
64389. In a 3 phase full wave regulator feeding resistance load connected in star, the possible range of firing angle a is
64390. Assertion (A): A dual converter may be circulating current type or non circulating current type.Reason (R): In circulating current dual converter only one converter can be operated at one time.
64391. Current chopping leads to
64392. A 3 phase bridge inverter is fed by 400 V battery. The load is star connected and has a resistance of 10 Ω per phase. The peak value of load current is
64393. In an SCR, the anode current is controlled by
64394. The rated current of a thyristor is 40 A. The holding current will be about :
64395. A cycloconverter is
64396. The number of leads in a power semiconductor diode are
64397. If ton and toff are the turn on and turn off times of a thyristor, then
64398. Assertion (A): The gate current of an SCR is always in the form of pulses. Reason (R): The gate losses, in pulse triggering, are low.
64399. UJT can be used for
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