Electrical Resistance
Characterizes the resistance of the materials against the flow of electric current
if the resistance of an electric circuit is small the current intensity will be high (water model: large diameter and short length pipes)
if the resistance of an electric circuit is high, the current intensity will be low (water model: small diameter and long pipes)
Electrical resistance (R) of a circuit defined as:
V: voltage at the sides of the circuit; I: electrical current intensity
units for resistance: V/A --> Ohm (?)
electrical resistance of wires: proportional with length and inversely proportional with diameter, depends strongly on material properties and temperature (resistivity: resistance of a wire with unit length and diameter)
materials with high resitivity: resistors
materials with low resistivity: conductors
Ohm’s law can be applied for each tinny portion of an electrical circuit!