# GATE Questions & Answers of Characteristics of Semiconductor Power Devices: Diodes, Thyristor, Triac, GTO, MOSFET, IGBT

## What is the Weightage of Characteristics of Semiconductor Power Devices: Diodes, Thyristor, Triac, GTO, MOSFET, IGBT in GATE Exam?

Total 15 Questions have been asked from Characteristics of Semiconductor Power Devices: Diodes, Thyristor, Triac, GTO, MOSFET, IGBT topic of Power Electronics subject in previous GATE papers. Average marks 1.60.

Four power semiconductor devices are shown in the figure along with their relevant terminals. The device(s) that can carry dc current continuously in the direction shown when gated appropriately is (are)

For the power semiconductor device IGBT, MOSFET, Diode and Thyristor, which one of the following statements is TRUE?

A steady dc current of 100 A is flowing through a power module (S, D) as shown in Figure (a). The V-I characteristics of the IGBT (S) and the diode (D) are shown in Figures (b) and (c), respectively. The conduction power loss in the power module (S, D), in watts, is ________.

The voltage $\left({v}_{s}\right)$ across and the current $\left({i}_{s}\right)$ through a semiconductor switch during a turn-ON transition are shown in figure. The energy dissipated during the turn-ON transition, in mJ, is _______.

Figure shows four electronic switches (i), (ii), (iii) and (iv). Which of the switches can block voltages of either polarity (applied between terminals ‘a’ and ‘b’) when the active device is in the OFF state?

Thyristor T in the figure below is initially off and is triggered with a single pulse of width 10 μs. It is given that $L=\left(\frac{100}{\mathrm{\pi }}\right)\mu \mathrm{H}$ and $C=\left(\frac{100}{\mathrm{\pi }}\right)\mu \mathrm{F}$. Assuming latching and holding currents of the thyristor are both zero and the initial charge on C is zero, T conducts for

The typical ratio of latching current to holding current in a 20 A thyristor is

Circuit turn-off time of an SCR is defined as the time

A voltage commutated chopper circuit, operated at 500Hz, is shown below.

If the maximum value of load current is 10A, then the maximum current through the main (M) and auxiliary (A) thyristors will be

The circuit shows an ideal diode connected to a pure inductor and is connected to a purely sinusoidal 50Hz voltage source. Under ideal conditions the current waveform through the inductor will look like

Match the switch arrangements on the top row to the steady-state V-I characteristics on the lower row. The steady state operating points are shown by large black dots.

In the circuit of adjacent figure the diode connects the ac source to a pure inductance L.

The diode conducts for

The circuit in the figure is a current commutated dc-dc chopper where, ThM is the main SCR and ThAUX is the auxiliary SCR. The load current is constant at 10 A. ThM is ON. ThAUX is trigged at t = 0. ThM is turned OFF between

A 1:1 Pulse Transformer (PT) is used to trigger the SCR in the adjacent figure. The SCR is rated at 1.5 kV, 250 A with IL = 250 mA, IH = 150 mA, and IGmax = 150 mA, IGmin = 100 mA. The SCR is connected to an inductive load, where L = 150 mH in series with a small resistance and the supply voltage is 200 V dc. The forward drops of all transistors/diodes and gate-cathode junction during ON state are 1.0 V.

The resistance R should be