DC Voltage Control

We can do this with the help of a suitable chopper. Both types are available either step up or step down.

By usage of buck (step down) or boost converter(step up)...

this can be done with capacitors

There is no direct method for boosting dc voltage. Bucking is very easy. Using a voltage regulator circuit which includes an active pass element voltage can be brought down. However, there is substantial power loss. You can even use chopper circuit to buck dc, which has very low loss. To boost dc, you need to invert it to ac at suitable frequency and use suitable transformer to step up and rectify back to dc.

this can be done by using chopper.chopper is a dc equivalent of a.c transformer to which d.c input which is to be stepped up is applied at input terminals and output is taken from output terminals which is stepped up or stepped down as desired.for stepping up step up chopper is used and for stepping down step down or buck chopper is used.

A chopper is nothing but a thyristor/SCR/transistor circuit which operates with the principle of PWM (Pulse Width Modulation). If you need to boost DC voltage with chopper, additional circuits including a ferrite core transformer, rectifier may also be required. Can you please explain how only a chopper can be used to boost DC voltage?