ABSTRACT
At the end of this chapter you should be able to: • appreciate that electrical resistance depends on four
factors • appreciate that resistance R= ρl
a , where ρ is the
resistivity • recognize typical values of resistivity and its unit
• perform calculations using R= ρl a• define the temperature coefficient of resistance, α
• recognize typical values for α • perform calculations using Rθ =R0(1+αθ)
3.1 Resistance and resistivity
The resistance of an electrical conductor depends on 4 factors, these being: (a) the length of the conductor, (b) the cross-sectional area of the conductor, (c) the type of material and (d) the temperature of the material.
