What is Direct Current ?

Telephone exchange communication equipment

The negative polarity is achieved by grounding the positive terminal of power supply system and the battery bank.

High-voltage direct current

Telecommunication

DC is defined as the “unidirectional” flow of current

current only flows in one direction.

Voltage and current can vary over time so long as the direction of flow does not change.

To simplify things, we will assume that voltage is a constant.

we assume that a AA battery provides 1.5V, which can be described in mathematical terms as

What does this mean? It means that we can count on most DC sources to provide a constant voltage over time.

Almost all electronics projects and parts for sale on SparkFun run on DC

Everything that runs off of a battery

Direct current can be defined as whose average value when reckoned over single time period is not equal to Zero

It can be positive or negative value but basically

It's differentiated from Ac signal as average value when computed over single time period of this signal is zero

Pure DC value is constant value whose frequency is 0 which can be apprehended as frequency means repititi -on of value for specific time interval but iteration is not taking place for DC signal..

Direct current is defined as the current which have no frequency.

Direct current is the current where in frequency is "O"

A direct current is that current which does not changes its polarity with time. But it can be a fluctuating direct current means it can have different value of current over a period of time but never changes its polarity.