Question: A thyristor is basically________?

• 1. PNPN device
• 2. A combination of diac and triac
• 3. A set of SCRs
• 4. A set if SCR,diac and triac

Question: A PNPN device having two gates is ___________?

• 1. Diac
• 2. Triac
• 3. SUS
• 4. BCS

Question: A silicon controlled racitifier (SCR) is a ____________?

• 1. Unijunction device
• 2. Device with three junction
• 3. Device with four junction
• 4. None of the above

Question: A thyristor equivalent of a thyratron tube is a _________?

• 1. Diac
• 2. Triac
• 3. Silicon controlled-rectifier SCR
• 4. None of above

Question: A Triac is a ______________?

• 1. 2 terminal switch
• 2. 2 terminal bilateral switch
• 3. 3 terminal bilateral switch
• 4. 3 terminal bidirectional switch

Question: Spacers are provided between adjacent coils?

• 1. to provide free passage to the cooling oil
• 2. to insulate the coils from each other
• 3. both A and B
• 4. none of the above

Question: No-load current of a transformer has_____________?

• 1. has high magnitude and low power factor
• 2. has high magnitude and high power factor
• 3. has small magnitude and high power factor
• 4. has small magnitude and low power factor

Question: Transformer breaths in when_______________?

• 1. load on it increases
• 2. load on it decreases
• 3. load remains constant
• 4. none of the above

Question: The maximum efficiency of a distribution transformer is____________?

• 1. at no load
• 2. at 50% full load
• 3. at 80% full load
• 4. at full load

Question: Power transformers are designed to have maximum efficiency at___________?

• 1. nearly full load
• 2. 70% full load
• 3. 50% full load
• 4. no load