Q: What are four quadrant operations?
A: Four quadrant operation of DC motor means operating a DC motor in Forward, Reverse, Forward brake and Reverse brake.
Q: Which microcontroller is used in this project?
A: This project does not use any microcontroller.
Q: What is the rating of the DC motor used?
A: High speed DC motor- 5 volt is used.
Q: In which mode 555 timers is used?
A: 555 timers is used in Monostable Mode
Q: What is the use of relay in this project?
A: The relay is used to change the supply polarity for braking operation in both directions
Q: What is the formula for calculating smoothing capacitor value?
A: There is some approximated formula .Peak to peak ripple voltage = Load current in amps / (2*line frequency in hertz *capacitance in farads). But as rule of thumb for 1 A current 1000uF is best. Thus it is load dependent.