Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
A step-down chopper is also called as a_____.
First-quadrant chopper
Second-quadrant chopper
Third-quadrant chopper
Fourth-quadrant chopper
First-quadrant chopper
A step-down chopper, or buck converter, is classified as a first-quadrant chopper because it allows power flow only from the source to the load while maintaining positive output voltage and positive output current. In this configuration, both the voltage V0тАЛ and the current I0тАЛ remain positive, operating strictly in the first quadrant of the VтИТI plane.
A step-down chopper, or buck converter, is classified as a first-quadrant chopper because it allows power flow only from the source to the load while maintaining positive output voltage and positive output current. In this configuration, both the voltage V0тАЛ and the current I0тАЛ remain positive, operating strictly in the first quadrant of the VтИТI plane.
V0тАЛ=╬▒VsтАЛ тАФ Output voltage of a step-down chopper, where ╬▒ is the duty cycle
╬▒=TTonтАЛтАЛ тАФ Definition of duty cycle ratio
In a first-quadrant chopper, the switch (typically a MOSFET or IGBT) is turned ON and OFF periodically. When the switch is ON, the source voltage is applied to the load; when the switch is OFF, the load current freewheels through a diode. Because the load voltage and current always maintain the same polarity as the source, the chopper acts as a single-quadrant device.
Operates only in the first quadrant of the V-I coordinate system.
The output voltage V0тАЛ is always less than the source voltage VsтАЛ.
Suitable for driving passive DC loads or motor loads requiring unidirectional current.
Utilizes a freewheeling diode to maintain load current during the switch-off period.
High efficiency due to switching operation
Smooth control of output voltage
Output is strictly unidirectional
Requires high-frequency switching
DC traction motor control
Battery charging circuits
Variable speed DC drives
A step-down chopper is also known as a Class-A chopper.
Option B (Second-quadrant) refers to a step-up chopper (regenerative), while options C and D represent multi-quadrant converters for reversing power flow or current direction.
A is correct тАФ A step-down chopper operates solely in the first quadrant, providing positive output voltage and current.
Always remember that in chopper classification, the quadrant defines the polarity of voltage and current; Class A is 1st quadrant, Class B is 2nd, Class C is 1st and 2nd, and Class D is 1st and 4th.