MOD 4 LECTURE  5                                      AC AND DC

In this lecture you will learn about:

DC - direct current
DC is direct current, the electrons actually move through material. However, ELECTRONS MOVE LIKE MOLASSES IN JANUARY.

However, when you get into your car and turn on the headlights, they come on "instantly". What happens when you hit the switch is that you connect the circuit and the ELECTRICAL FIELD is established. There are electrons all along the wire.

D.C. AND THE EMS!  CLICK HERE 

The ELECTRICAL FIELD moves at the speed of light. Once the FIELD is on, the electrons at the other end begin to flow. It is like the conduit from the top of Hoover Dam is always full of water, just the gate needs to be opened for water to flow immediately.

DC is not just for batteries, all electronic devices use DC, like your computer, TV, stereo, etc. There is a converter inside that converts AC to DC.

FLASHLIGHT

POWER ADAPTER FOR COMPUTER

 


 
AC - alternating current
A.C.  CLICK HERE 

- AC is alternating current.

that is, instead of electrons flowing in one direction down the wire like in DC, the electrons just move back and forth with NO NET FORWARD MOVEMENT DOWN THE WIRE.

well.. that is nice, but how doesnt explain how current is going to flow

in the case of alternating current, the movement of the electrons carries the ENERGY OF THE ELECTRICAL FIELD which moves down the wire at the speed of light

alternating current is created in a wire by rapidly changing the direction of a magnetic field

-- items that use alternating current draw A LOT of amperage

A CONVERTER FROM DC to AC (heating)


AC CURRENT ITEMS

REVIEW QUESTIONS:
Compare ac and dc in terms of what the electrons are doing  and what the waves look like.
speed
What is ac?  what actually uses ac current?
What is dc?  what kind of devices use dc current?
How is electrical current and magnetism related?
Why when you turn on your d.c. lights in the car do they come on instantly instead of slowly since electrons move so slowly?
How fast does an electrical field move?
How is alternating current created?