A transformer is used to step down a.c.voltage. What appliance do you use to step down d.c. voltage ?

A transformer is used to step down a.c. voltage. What appliance will you used to step down a d.c.voltage?

A transformer steps up or steps down

A transformer steps up or asteps down

Name any appliances that can step down d.c. voltage.

Name any appliance that can step down d.c. voltage.

Why cannot a transformer be used to step up d.c. voltage ?

Why transformer cannot be used the step up D.C. voltage?