DC Chopper : A DC chopper is a static device that converts fixed DC input voltage to a variable DC output voltage. The chopper is simply DC to DC converter. A Chopper is simply an 'on-off switch that either connects load to the supply or disconnects load from the supply and produces a chopped load voltage from a constant input supply.

AC Chopper: The AC voltage magnitude can be changed by two methods.The well-known first method is by means of step-up and The step-down transformers. In this method, change in voltage depends on the value of transformation ratio of the transformer. The second method of changing magnitude of an AC voltage is by means of a solid-state switch. In this method, the AC input voltage is switched on and off periodically by means of suitable switch. Voltage changing circuits employing semiconductor devices as a static switch are known as AC Choppers.

Step Down Chopper : A Chopper is simply an 'on-off' switch that either connects load to the supply or disconnects load from the supply at a fast speed and produces a chopped load voltage from a constant input supply.. In Step Down chopper the average output voltage VO is less than the input voltage VS. Thus load voltage can be controlled by varying duty cycle.

Step Up Chopper: A Chopper is simply an 'on-off' switch that either connects load to the supply or disconnects load from the supply at a fast speed and produces a chopped load voltage from a constant input supply. In Step Up chopper the average output voltage VO is greater than the input voltage VS. Thus load voltage can be controlled by varying duty cycle.