Electrical Engg (EEE) - MCQ Practice Questions

The power factor of a thyristor-based rectifier with firing angle 60° is approximately:

In a current-source inverter (CSI), the DC link component is typically:

A thyristor has a forward breakover voltage of 800V and a holding current of 200mA. What is the minimum gate current required to trigger the device if the gate sensitivity is 40mA/V?

In a boost converter operating in continuous conduction mode (CCM) with duty cycle D=0.6, input voltage 24V, and output voltage 60V, what is the efficiency if losses are 5%?

A PWM inverter produces an output frequency of 50Hz with a carrier frequency of 10kHz. What is the modulation index if the peak modulating signal is 0.8V and the peak carrier signal is 1V?

In a half-bridge inverter, what is the minimum dead time required to prevent shoot-through if the switching frequency is 20kHz?

Which protection method is MOST suitable for protecting a thyristor against voltage transients in industrial applications?

A current-controlled PWM rectifier maintains unity power factor. If the input current harmonic distortion THD is 3%, what is the approximate displacement power factor?

Which semiconductor device combination is used in a cycloconverter to convert AC-to-AC with frequency reduction?

In a matrix converter (direct AC-to-AC), how many bi-directional switches are required for three-phase input and three-phase output?

A three-phase PWM rectifier with active front-end reduces grid distortion to THD < 5%. This is primarily achieved by:

In a boost converter operating in continuous conduction mode (CCM), if the input voltage is 24V, output voltage is 48V, and switching frequency is 100kHz, what is the duty cycle of the converter?

A moving coil galvanometer has a coil resistance of 10 Ω and gives full-scale deflection for 5 mA current. What shunt resistance is required to convert it into an ammeter of range 0-5 A?

Which bridge circuit is most suitable for measuring an unknown capacitance?

In a Wheat stone bridge, the null deflection is obtained when the ratio of resistances satisfies which condition?

A moving iron instrument reads the same for both AC and DC because it:

A thermocouple is used to measure temperature because it:

The mutual inductance between two coils is independent of:

A platinum resistance thermometer (RTD) follows which relationship between resistance and temperature?

A Hall effect sensor is primarily used to measure: