What is Electricity?

1
What is Electricity?

• How do we produce Electricity?
• What are the different types of current and how
  are they produced?

2
What is Electricity

• Electricity involves the interaction of positive
  and negative charges
• Electricity is essentially the movement of charge
• Electric current is the flow of charge through a
  conductor

3
Key Electricity terms

1. Voltage Force pushing electrons
2. Current number of electrons flowing frequency
   of e- flow
3. Resistance how easy or difficult it is for e- to
   flow
4. Conductors have low resistance
5. Insulators have high resistance

4
How do we produce electricity?

1. Static friction
2. Generators hydroelectric, nuclear, coal, natural
   gas, biomass, tidal, hand crank radio
3. Magnetism
4. Solar cells

5. Chemical reactions batteries 6.
Piezoelectricity using crystalline flux
5
Different types of Electric current

• DC Direct Current
• This is current that flows in one direction from
  positive to negative charged areas

• ACAlternating Current
• This is current that flows back and forth,
  alternating direction of flow

6
What makes DC?

• Static discharges
• Batteries
• DC converters/
• adapters

7
Static Electricity

• Made by the transfer of charge due to friction
• Very dry air promotes static electricity, moist
  or humid air reduces it

• Lightening is the greatest form of static
  electric discharge.

8
DC and Batteries

• Batteries use a chemical reaction to produce a
  flow of charge.
• Batteries can be Wet Cell or Dry Cell in nature

9
More about Batteries

• Wet Cells
• Used in cars, lawn mowers, boats
• Often have lead compound anodes and cathodes and
  use a liquid electrolyte

• Maximum voltage per cell is 2 Volts
• A simple one can be made with a copper strip, a
  zinc strip and an electrolyte such as
  Hydrochloric acid or even Lemon Juice

10
More about Batteries

• Dry Cells
• Used in small appliances, radios, remote controls
• Often made of a zinc case and carbon center rod
  and a dry or paste electrolyte

• Maximum voltage per cell is 1.5 Volts

11
Dry Cell types

• The size AAA, AA, C, and D batteries that we
  use are single dry cells they are not true
  batteries
• A battery is 2 or more cells wired together

• The maximum voltage available from any single dry
  cell is 1.5 volts, so why so many different
  types. AAA1.5V
• D1.5V

12
More about batteries and single cells

• So how is a 9V built?
• How does a car battery have 12V?
• How does a camping lantern battery have 6V while
  the same size hobby battery has 1.5V?

13
More about batteries and single cells

• A 9V battery has 6 smaller dry cells in it
• A car battery has 6 smaller wet cells
• A lantern battery has 4 dry cells wired in series
  and a hobby battery has 4 dry cells wired in
  parallel

14
Good and Bad of Wet and Dry cells

• Wet Cells
• Bad often use acid electrolytes
• Bad tend to be large
• Good can be recharged
• Good produce more Voltage per cell

• Dry Cells
• Bad cannot be recharged
• Bad only produce 1.5 Volts per cell
• Good some can be recharged
• Good smaller and lighter and usually do not
  corrode appliance

15
DC Adapters

• Used to convert AC to DC for appliance use
• Range in sizes from very small Voltages to very
  large voltages
• A telephone may use 9 V while a laptop computer
  often uses 18 V

16
What makes AC?

• Generators change mechanical energy into
  electrical energy with the use of magnets
• It is available through any wall outlet

17
How does a generator work?

• A generator turns a magnet in between coils of
  wire and the magnetic field induces an electric
  charge flow in the coils of wire

• Different directions of current flow are created
  as the magnet turns causing the direction
  changing characteristic of AC

18
More about AC

• AC is produced at certain frequencies of cycles
  due to the spinning of the magnets in the
  generators used
• The frequency of these cycles varies around the
  world

19
AC Stats.

• The U.S. produces AC at 60Hz (cycles per second)
  and household outlets are 120 Volts and large
  appliance outlets are 220 V

• The UK is at 50Hz and 230V
• Japan is at 50/60Hz and 100V
• Australia is at 50Hz and 230V

20
Problems with travel and different AC frequencies

• If you purchase an appliance that is only set to
  US it will not work in most other countries
• The plugs are not the same either
• You would need to purchase a set of adapter plugs
  and purchase appliances that are adaptable

21
Possible Pros and Cons of AC and DC

• Pros AC is easier/cheaper to produce and
  control in large quantities
• Pros DC is needed for many electronic components
  and it is easy to transport

• Cons AC production requires a generator and
  other supplies
• Cons DC batteries are expensive and have a
  limited lifespan