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In a GTO the n+ layer forms the
Answer: c Explanation: The bottom n+ layer forms the cathode
Answer: c Explanation: The bottom n+ layer forms the cathode
See lessThe equivalent circuit of SUS (Silicon Unilateral Switch) consists of
Answer: c Explanation: It is a diode connected in anti-parallel with a PUT
Answer: c
Explanation: It is a diode connected in anti-parallel with a PUT
See lessThe Programmable Unijunction Transistor (PUT) turns on & starts conducting when the
Answer: b Explanation: The device only starts to conduct when the forward anode to cathode voltage exceeds the applied gate to cathode voltage.
Answer: b
Explanation: The device only starts to conduct when the forward anode to cathode voltage exceeds the applied gate to cathode voltage.
See less_________ device from the thyristor family has its gate terminal connected to the n-type material near the anode.
Answer: c Explanation: PUT is Programmable Unijunction Transistor which is a p-n-p-n device just like the SCR with its gate connected to the n-type material.
Answer: c
Explanation: PUT is Programmable Unijunction Transistor which is a p-n-p-n device just like the SCR with its gate connected to the n-type material.
See lessSCRs with a rating of 1000 V & 200 A are available to be used in a string to handle 6 KV & 1 KV. Calculate the number of series & parallel units required in case the de-rating factor is 0.1. (Round off the fraction to the greatest & nearest integer)
Answer: a Explanation: DRF = 1-S.E Therefore 0.1 = (1-6000/1000Ns) = (1-1000/200Np) Ns = 6.6 = 7(say) Np = 5.5 = 6(say)
Answer: a Explanation: DRF = 1-S.E Therefore 0.1 = (1-6000/1000Ns) = (1-1000/200Np) Ns = 6.6 = 7(say) Np = 5.5 = 6(say)
See lessTwo parallel connect SCRs have same voltage drop (Vt) having rated current = 2I1. SCR-1 carries a current of I1=2.6 A whereas SCR-2 carries a current of I2=1.4 A. Find the string efficiency.
Answer: b Explanation: The total current would be I1+I2 & rated current is 2I1 String efficiency = (I1+I2)/2I1.
Answer: b
Explanation: The total current would be I1+I2 & rated current is 2I1 String efficiency = (I1+I2)/2I1.
See lessSCRs are connected in series. The string efficiency is 91%. SCRs 1, 2 & 3 have leakage currents 4 mA, 8 mA & 12 mA. Which SCR will block more voltage?
Answer: a Explanation: The SCR with lower leakage current block more voltage
Answer: a
Explanation: The SCR with lower leakage current block more voltage
See lessThe most practical way of obtaining a uniform distribution of series connected SCRs is to
Answer: b Explanation: For uniform distribution of voltage across series connected SCRs, a resistor of value R in parallel with each series connected SCR.
Answer: b
Explanation: For uniform distribution of voltage across series connected SCRs, a resistor of value R in parallel with each series connected SCR.
See lessWhen an extra SCR is connected in series with a string
Answer: b Explanation: DRF = 1 – String efficiency String Efficiency = Rating of the whole string/(rating of one SCR x number of SCRs) Extra SCR will reduce the string efficiency which in turn increase the DRF.
Answer: b
Explanation: DRF = 1 – String efficiency String Efficiency = Rating of the whole string/(rating of one SCR x number of SCRs) Extra SCR will reduce the string efficiency which in turn increase the DRF.
See lessThe measure of reliability of string is given by the factor
Answer: a Explanation: DRF is de-rating factor given by the above expression.
Answer: a
Explanation: DRF is de-rating factor given by the above expression.
See less