DC Power - definition

There are two types of current in electronic and electrical technology which are DC (Direct Current) and AC(Alternating Current).
In DC power, the current polarity remains constant means whether it'll stay on positive or negative related to time. The voltage value or amplitude can change with respect to time. Also, there is no frequency in the DC signal.
Application: most electronic devices use DC power as the main source such as computers, TV, mobile, sound system, etc. Primarily it is connected to an AC source and inside the device, it is converted to DC.