SOLUTION

• The DC choppers convert the input DC voltage into fixed or variable DC output.
• Chopper is essentially a power semiconductor switch, that is functionally represented by a switch SW inside a dotted box which also includes arrangements for closing and opening. The chopper periodically switches ON and OFF the supply voltage V_s to and from the load at any desired frequency.

• During the ON period, the chopper switch is dosed and the load voltage is equal to source voltage V_s assuming negligible voltage drop across the conducting device.
• During the off period, the chopper switch is open. But the load current flows through the freewheeling diode P_D. As a result, the load voltage reduces to zero assuming negligible voltage drop in the conducting diode.
• Alternate turn-on and turn-off of the chopper in a periodic manner produces a chopped dc voltage which appears like a pulse train across the load i.e (discontinuous Voltage).
• The current due to this voltage is shown flowing continuously in the load.