Common Sources of Electricity

Magnetism:

• This process used in electric generator and is the most common method used today (hydro dam)
  
  

Chemical Reactions:

• This process is used in batteries, electricity is produced by chemical reaction between electrodes and electrolyte
  

Light:

• This process used light as a source of energy.  Electricity is produced when light strikes a certain materials they release electrons.  This process is called photoelectric effect.  Used in solar panels.
  
  

Heat:

• The process use a flame, when two dissimilar metals are joined at one end and the junction is heated a small voltage will result.  This small voltage may used to operate safety devices or some temperature controls.  This device is called a thermocouple (controls gas valves)
  
  

Pressure:

• This process uses crystalline materials that produce electricity when exposed to pressure.  This is called Piezoelectricity
  
  

Friction:

• This process used two dissimilar materials which when rubbed together transfer electrons and produces a potential difference.  This is called Static Electricity
  
  

Resistance:

• Is the opposition to electron movement
• Little resistance……higher current
• More resistance……lower current