Q.Explain the working of DC to DC chopper circuit.

A DC chopper converts a fixed DC voltage into a variable DC output by rapidly switching a device (a MOSFET) between the source and the load and controlling the duty ratio. …

[!TLDR]

A MOSFET switch chops the DC supply ON/OFF; the average output $V_{av}=\frac{T_{ON}}{T}V_S$ is set by the duty ratio, varied by changing $T_{ON}$ at constant frequency.

A DC chopper is used to convert a DC voltage of fixed amplitude into a DC voltage of variable value; the output is controlled by controlling the duty cycle of the chopper. It is used for variable-voltage DC power supplies, battery chargers, switched-mode power supplies (SMPS) and DC motor control.

Working: A MOSFET is connected as a switch between the DC source $V_S$ and the load. When the MOSFET is switched ON (closed, by applying a proper gate pulse) the supply voltage is connected to the load; when it is switched OFF (opened, by removing the gate signal) the load is disconnected from the supply. For a resistive load the output voltage $V_o$ and output current $I_o$ follow the shape of the gate pulses, i.e. they equal the supply value during the ON interval and are zero during the OFF interval.

The average voltage impressed on the load is controlled by controlling the ratio of the ON-state interval to the total cycle duration. If $T$ is the period and $T_{ON}$ the ON time, the average output voltage is

$V_{av}=\frac{T_{ON}}{T}\,V_S$ …