Electrical Properties of Engineering Materials

Why Study the Electrical Properties of Materials?
Consideration of the electrical properties of materials is often important when materials selection and processing decisions are being made during the design of a component or structure. The electrical behaviors of the various materials are diverse. Some need to be highly electrically conductive (e.g., connecting wires), whereas electrical insulativity is required of others (e.g., the protective package encapsulation).

Electrical Conduction
OHM’S LAW
One of the most important electrical characteristics of a solid material is the ease with which it transmits an electric current. Ohm’s law relates the current I—or time rate of charge passage—to the applied voltage V as follows:

where R is the resistance of the material through which the current is passing. The units for V, I, and R are, respectively, volts (J/C), amperes (C/s), and ohms V/A.
The value of R is influenced by specimen configuration, and for many materials is independent of current. The resistivity is independent of specimen geometry but related to R through the expression: