18 Questions
What is the primary purpose of a diac in a triac-based circuit?
To trigger the triac into conduction
Which of the following is NOT a common application of a diac?
Voltage regulation
In a diac-triac based lamp dimmer circuit, what is the purpose of the series $R_4$-$C_1$ circuit across the triac?
To limit the rate of voltage rise across the triac during switch off
What is the purpose of using a diac to trigger a triac in a circuit?
To provide a more reliable and faster turn-on of the triac
What is the relationship between the breakover voltage and holding current of a diac?
The breakover voltage and holding current values are identical for the forward and reverse regions of operation
Which of the following is a key advantage of using a diac to trigger a triac in a circuit?
More reliable and faster turn-on of the triac
What is the key characteristic of an SCR that allows it to control the flow of AC power?
It can only conduct current in one direction
How can the phase angle of the gate voltage in an SCR circuit be adjusted?
By adjusting the variable resistance R1
What is the primary advantage of using a triac to control AC power, compared to an SCR?
Triacs can control both positive and negative half-cycles of AC
Which of the following is NOT a common application of a triac?
DC motor speed control
In the triac circuit shown in Fig. 21.11, what happens when the switch S is thrown to position 1?
The triac is cut off and the lamp is off
What is the primary reason triacs are often used as electronic on/off switches controlled by mechanical switches?
Triacs require low gate currents and voltages
What is the primary advantage of using semiconductor switching devices over electrical methods for controlling power flow?
They provide finer control over power flow.
Which of the following semiconductor switching devices can control alternating current in a load?
Triac
What is the primary limitation of a silicon controlled rectifier (SCR) that necessitates the use of a triac?
Both A and B
Which of the following semiconductor switching devices is used for controlled rectification, inversion, and regulation of power in a load?
All of the above
What is the primary purpose of using semiconductor switching devices in power control applications?
All of the above
Which of the following statements is true about triacs?
Triacs are three-terminal semiconductor switching devices.
Explore the principles behind controlling power to a load using semiconductor devices for more efficient and fine control. Learn about the advantages of semiconductor devices over traditional electrical methods in power regulation.
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