# Direct and alternating current

If we consider a graph i x t (intensity of electric current by time), we can classify the current according to the curve found, ie:

## Direct current

A current is considered continuous when it does not change its meaning, ie it is always positive or always negative.

Most electronic circuits work with direct current, although not all of them have the same "yield" as for their ix t curve, direct current can be classified by:

### Constant current

A direct current is said to be constant if its graph is given by a constant line segment, ie not variable. This type of current is commonly found in batteries.

### Pulsing Direct Current

Although it does not change its direction, pulsating direct currents periodically undergo variations and are not necessarily constant between two measurements at different time intervals.

The graph illustration above is an example of constant direct current.

This form of current is generally found in alternating current rectifier circuits.

## Alternating current

Depending on how the current is generated, it is periodically reversed, that is, sometimes positive and sometimes negative, causing the electrons to move back and forth.

This type of current is what we find when we measure the current found in the residential power grid, that is, the current measured in the sockets of our house.