A DC to DC converter is a type of switching regulated powersupply whose input is a DC voltage, it then switches that rapidly to make AC, which is applied to the primary of a transformer, the transformer then either steps up or down the voltage as desired, the AC from the secondary is then rectified and filtered to provide the output DC voltage. Regulation circuitry measures the output DC voltage, continuously adjusting the switching circuits on the input to keep the output constant.
Most switching regulated powersupplies are DC to DC converters with a simple unregulated rectifier and filter to convert the input AC to DC. Usually it is called a powersupply when it provides more than one output DC voltage or if its input is AC; whereas it is called a converter only if it provides just one output DC voltage and its input is DC. But most of the circuitry is the same in both cases.
To change the voltage.
Yes
It is the process of conversion of generated ac voltage into the armature of a dc generator to dc voltage at the terminal of the dc generator by use of pair of brushes and commutator. OR It is the process of conversion of given dc voltage at the terminal of the dc motor to ac voltage in the armature windings in a dc motor by use of pair of brushes and commutator.
Conversion of electrical energy into mechanical energy
The voltage in your house is AC. It is in the form of a sine wave that goes positive and negative 60 times a second. To charge a battery you need DC so you do an AC to DC conversion and then apply the DC to the battery charging circuit that applies the correct charging current to the battery and checks on the state of the charge.
DC-DC conversion offers the advantage of a bifurcated power source. AC can be rectified and filtered to supply power under normal conditions at say, 17VDC fed to a 9VDC regulator to power the circuit. A 12VDC battery can serve as an alternate feed to the circuit for times when the AC source fails -- and it is connected to the same 9VDC regulator. Another benefit of DC-DC conversion is isolation to the circuit from noisy events.
ac
The conversion from one DC voltage to another requires electronic circuitry.
a form of low voltage DC to high voltage AC power conversion circuit.
In the near Future we will have photo-voltaic {Solar Panel} roofing shingles! Wow! Every home will need a DC storage component and a DC to AC conversion system.
George Westinghouse promoted AC over long distances. George Westinghouse did not promote a conversion to DC for household appliances like the system we have today.
Yes - or at least, there was one, a DC-3 conversion: http://www.douglasdc3.com/polair/polair.htm