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Heat dissipation from heat sink mainly takes place by
Answer: b Explanation: Heat DISSIPATION (rejection of heat to the atmosphere) takes place through convention only.
Answer: b
See lessExplanation: Heat DISSIPATION (rejection of heat to the atmosphere) takes place
through convention only.
Pav x (θjc + θcs + θsA) =
Answer: c Explanation: Pav = (Tj – Ta)/θjA θjA = (θjc + θcs + θsA).
Answer: c
See lessExplanation: Pav = (Tj – Ta)/θjA
θjA = (θjc + θcs + θsA).
The sink to ambient thermal resistance of SCR θsA
Answer: d Explanation: It does not depend on any of the device configurations.
Answer: d
See lessExplanation: It does not depend on any of the device configurations.
Which of the following thermal resistance parameters depends on the size of the device and the clamping pressure?
Answer: b Explanation: The case-to-sink thermal resistance depends on the size of the device, pressure, grease between the interface, etc.
Answer: b
See lessExplanation: The case-to-sink thermal resistance depends on the size of the device,
pressure, grease between the interface, etc.
The total thermal resistance between junction and ambient θjA is 10°C/W. θjc is 2°C/W. θcs is 4°C/W. θsA = ?
Answer: a Explanation: θjA = θjc+ θcs+ θsA.
Answer: a
See lessExplanation: θjA = θjc+ θcs+ θsA.
Inter-digitating of gate-cathode regions in SCR devices improves the
Answer: b Explanation: Inter-digitating is the inter-mixing of the gate-cathode area to improve the di/dt ratings. di/dt rating is improved by providing more cathode conduction area during the delay and rise time.
Answer: b
See lessExplanation: Inter-digitating is the inter-mixing of the gate-cathode area to improve the
di/dt ratings. di/dt rating is improved by providing more cathode conduction area during
the delay and rise time.
Thyristors are used in electronic crowbar protection circuits because it possesses
Answer: a Explanation: Crowbar protection circuits have high surge current capabilities.
Answer: a
See lessExplanation: Crowbar protection circuits have high surge current capabilities.
The thyristor has the following specifications Vs = 400 V (di/dt)max = 25 A/μsec Find the value of L
Answer: c Explanation: As soon as the switch is closed, C acts like a S.C & the voltage equation gives, Vs = (Rs + Rl) I + L di/dt Solve the above D.E. di/dt = Vs/L e-t/τ di/dt is maximum at t = 0, substitute the above given values & find L
Answer: c
See lessExplanation: As soon as the switch is closed, C acts like a S.C & the voltage equation
gives,
Vs = (Rs + Rl) I + L di/dt
Solve the above D.E.
di/dt = Vs/L e-t/τ
di/dt is maximum at t = 0, substitute the above given values & find L
False triggering of the SCRs by varying flux & noise is avoided by using
Answer: b Explanation: Shielded cables provide isolation from outside noise.
Answer: b
See lessExplanation: Shielded cables provide isolation from outside noise.
Over-current protection in SCRs is achieved through the use of
Answer: c Explanation: FACLF stands for Fast Acting Current Limiting Fuse.
Answer: c
See lessExplanation: FACLF stands for Fast Acting Current Limiting Fuse.