Electricity/Electricity generator
Electricity generators
Source of DC Electricity Electricity types Mathematical formula Electrolysis 
DC Electrovoltaic DC Photonvoltaic 
DC Electromagnetic inducton 
AC
Electricity types
Electricity falls into the 2 types AC (Alternating Current) and DC (Direct Current)
AC (Alternating Current)
Electricity provides a sinusoidal time varying voltage over time
When connect AC source to ground, current starts to flow from the source to ground
From above,
DC (Direct Current)
Electricity provides constant voltage over time
When connect AC source to ground, current starts to flow from the source to ground