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The finger voltage of an SCR is
Answer: a Explanation: Finger voltage is the minimum value of Vak (anode to cathode voltage) to turn on the device with gate triggering, it is to be avoided for accidental turn-on of the device.
See lessAnswer: aExplanation: Finger voltage is the minimum value of Vak (anode to cathode voltage) to
turn on the device with gate triggering, it is to be avoided for accidental turn-on of the
device.
The voltage safety factor (VSF) for an SCR is the ratio of
Answer: c Explanation: It is peak repetitive reverse voltage/ the maximum value of input voltage(Vm).
Answer: c
See lessExplanation: It is peak repetitive reverse voltage/ the maximum value of input
voltage(Vm).
The gate-source voltage is Es = 16 V and the load line has a slope of 128 V/A. Calculate the gate current for an average gate power dissipation of 0.5 W.
Answer: a Explanation: Load line is nothing but Rs Es = 16V Vg.Ig = 0.5 Rs = 128 We have Es = Ig x Rs + Vg.
Answer: a
See lessExplanation: Load line is nothing but Rs
Es = 16V
Vg.Ig = 0.5
Rs = 128
We have Es = Ig x Rs + Vg.
Latching current for an SCR is 100 mA, DC source of 200 V is also connected from the SCR to the L load. Compute the minimum width of the gate pulse required to turn on the device. Take L = 0.2 H.
Answer: b Explanation: For L load, E = L di/dt I = E/L t Therefore, 0.100 = 200t/0.2 T = 100 μsec.
Answer: b
See lessExplanation: For L load, E = L di/dt
I = E/L t
Therefore, 0.100 = 200t/0.2
T = 100 μsec.
The two transistor model of the SCR can obtained by
Answer: d Explanation: The two transistor model consists of p-n-p and n-p-n transistors, of which the middle n-p layer is common in both the transistors.
Answer: d
See lessExplanation: The two transistor model consists of p-n-p and n-p-n transistors, of which
the middle n-p layer is common in both the transistors.
For an SCR, the gate-cathode characteristic has a slop of 130. The gate power dissipation is 0.5 watts. Find Ig
nswer: c Explanation: Vg/Ig = 130 .. (given) Vg.Ig = 0.5 watts .. (given) use both the given data & find the gate current.
nswer: c
See lessExplanation: Vg/Ig = 130 .. (given)
Vg.Ig = 0.5 watts .. (given)
use both the given data & find the gate current.
The average gate power dissipation for an SCR is 0.5 Watts the voltage applied to the gate is Vg = 10 V. What is the maximum value of current Ig for safe operation
Answer: c Explanation: Vg.Ig = 0.5 W, the power dissipation mustn’t exceed the average power dissipation.
Answer: c
See lessExplanation: Vg.Ig = 0.5 W, the power dissipation mustn’t exceed the average power
dissipation.
Higher the magnitude of the gate pulse
Answer: a Explanation: Lesser time is required to inject the charges & turn on the device with higher gate pulse magnitude.
Answer: a
See lessExplanation: Lesser time is required to inject the charges & turn on the device with
higher gate pulse magnitude.
A tangent drawn from the Y-axis to the Pavg on the gate characteristics gives the value of the
Answer: b Explanation: It gives the min gate to source resistance
Answer: b
See lessExplanation: It gives the min gate to source resistance
The area under the curve of the gate characteristics of thyristor gives the
Answer: d Explanation: As the gate characteristics is a plot of Ig vs Vg consisting of two curves one for the maximum values & other for the minimum the area between them gives the total average gate power dissipation. (A very important parameter in designing of the triggering circuits)
Answer: d
See lessExplanation: As the gate characteristics is a plot of Ig vs Vg consisting of two curves one
for the maximum values & other for the minimum the area between them gives the total
average gate power dissipation. (A very important parameter in designing of the
triggering circuits)