The circuit is connected as shown in the figure. The control DC voltage (Vc) can be varied between 0.1 to 0.9 to change the duty ratio. The Inductance value can be changed to see what is the minimum value of L for which continuous conduction is maintained especially in a buck converter.
For all the above three DC-DC converters, the circuit can be analysed by changing (a) duty ratio (b) frequency of operating the switch (c) by varying the load connected (d) by varying the filter capacitance and (e) inductance values.
The frequency is varied by varying the saw tooth waveform frequency (Vsaw). The load resistance, inductance and capacitance can also be varied according to the requirement.