What does SCR stand for?
A
Silicon Current Regulator
B
Solid Controlled Rectifier
C
Silicon Controlled Rectifier
D
Semiconductor Current Rectifier
Analysis & Theory
SCR stands for Silicon Controlled Rectifier, a widely used thyristor.
What is the control terminal of an SCR?
Analysis & Theory
The Gate terminal is used to trigger the SCR into conduction mode.
What is the main application of SCRs?
B
Controlled rectification and motor speed control
Analysis & Theory
SCRs are mainly used in controlled rectifiers and AC/DC motor control.
Which device can conduct in both directions and is used in AC applications?
Analysis & Theory
TRIACs are bidirectional devices commonly used for AC loads like lamps and motors.
What is the function of a Diac in a TRIAC circuit?
Analysis & Theory
Diacs are used to trigger the TRIAC by delivering a sudden voltage breakover.
What type of control signal does an IGBT require?
Analysis & Theory
IGBTs are voltage-controlled devices; gate voltage turns them on/off.
Which device is known for combining MOSFET input and BJT output characteristics?
Analysis & Theory
IGBT combines the easy drive of a MOSFET with the output efficiency of a BJT.
Which device cannot be turned off by the gate signal once turned on?
Analysis & Theory
An SCR requires the anode current to fall below holding current to turn off.
What is the application of TRIAC in households?
B
Heater and fan speed controllers
Analysis & Theory
TRIACs are used in household appliances for dimming and speed control.
What is the typical use of Power BJTs?
C
High current amplification and switching
Analysis & Theory
Power BJTs are used in high current switching circuits like inverters and SMPS.
What is the on-state condition for an SCR?
A
Positive gate signal and anode-to-cathode voltage
D
High resistance at cathode
Analysis & Theory
SCR conducts when forward biased and triggered with a gate pulse.
In which device does latching current matter?
Analysis & Theory
SCR must reach latching current level after gate triggering to remain conducting.
Which of the following devices is *not* bidirectional?
Analysis & Theory
SCR is a unidirectional device, unlike TRIAC and Diac which are bidirectional.
What happens when IGBT gate voltage is removed?
A
It turns off immediately
B
It continues to conduct
C
It triggers other devices
Analysis & Theory
IGBT turns off when the gate voltage is removed, unlike SCR which needs current interruption.
Which device is best for high-speed switching?
Analysis & Theory
IGBT is ideal for high-speed switching due to its fast response and low losses.
Which of the following devices is used in light dimmers?
Analysis & Theory
TRIACs are used in light dimmers due to their ability to control AC power.
What is a typical application of IGBT?
A
Audio signal amplification
C
Electric vehicle motor control and inverters
D
Switching in analog radios
Analysis & Theory
IGBTs are widely used in EV motor drives, UPS systems, and industrial inverters.
Which is a disadvantage of Power BJTs?
C
Requires high base current
Analysis & Theory
BJTs require significant base current to stay in conduction mode.
Which component is most suitable for controlled rectification?
Analysis & Theory
SCRs are preferred in controlled rectifier circuits due to their ability to delay conduction.
What determines the turn-off of a TRIAC?
B
Zero crossing of current
Analysis & Theory
A TRIAC turns off automatically at the natural zero crossing of AC current.