5:Electric Charges and Fields
9:Current and Resistance
11:Magnetic Forces and Fields
12:Sources of Magnetic Fields
Current and Resistance
Current (1A=1C/s) where (density, charge, drift velocity) of the carriers.
▭ , is the perpendicular area, and is current density. is electric field, where is resistivity.
▭ Resistivity varies with temperature as . Similarily, where is resistance (Ω)
▭ Ohm's law ▭ Power
Electric current: 1 Amp (A) = 1 Coulomb (C) per second (s)
= (density, charge, speed, Area)
where =current density.
= electric field where = resistivity
, and ,
where is resistance