Lesson 8: Changes in electrical current

Engage

While you have completed your practical circuits you will have been using DC power.

Look at the symbols next to both DC and AC, start to make predictions about what DC and AC could mean.

_Current

Defintions.

Voltage

What makes this current?

Storage

Motors

Voltage drop

What can it be used for?

Converting to the other current

Direct Current

Direct Current (DC) refers to a unidirectional current (all electrons moving in one direction).

This means voltage will be constant over time (it does not increase or decrease).

DC power can be directly produced by batteries, fuel cells and solar panels.

DC power can be easily stored into batteries by converting in chemical energy.

A DC motor is a lot more complicated to make compared to an AC motor.

DC current has high amounts of voltage drop over distances.

DC current can usually only be used for small appliances.

Converting DC into AC is very difficult it requires fast and complicated circuits.

Alternative Current

Alternative Current (AC) refers to a multidirectional current (all electrons moving in one direction then shift and can go in another direction).

This means voltage will change from positive to neagtive.

AC power can be directly produced by generators, dyanmos and turbines.

AC power cannot be stored, it must be converted to DC to be stored.

An AC motor is easy to make and has a higher power output.

AC current has can travel well over long distances with limited voltage drop.

AC current can be used for most high powered deviced locations, such as homes and industry applications.

Converting from AC to DC is a lot more easy, we can prevent currents that move in one direction.