Answer :
Final answer:
The correct answer is the Buck-boost chopper, as it can output a current that is always positive with a voltage that can either be positive or negative, providing flexibility in voltage regulation.
Explanation:
The type of chopper whose output current is always positive but output voltage can be positive or negative is called a Buck-boost chopper. Unlike step-up and step-down transformers which either increase or decrease voltage, the buck-boost chopper is capable of doing both. Keeping the output current in one direction while modulating the output voltage polarity and magnitude allows for extensive control in power supply and conversion systems.
Transformers, based on their construction, can either increase voltage (step-up transformer), decrease voltage (step-down transformer), or provide a variable output. The efficiency of transformers is generally high, often exceeding 99%, making power input approximately equal to power output, given by the relationship Pp = IpVp = IsVs = Ps.
