felületellenállást

Felületellenállás, often abbreviated as R_s, is a measure of how strongly a material opposes the flow of electric current across its surface. It is particularly relevant when dealing with thin films, conductive coatings, and materials where current flow is predominantly confined to the surface layer. The unit of surface resistance is ohms per square (Ω/□).

The concept of surface resistance arises from considering a square piece of a conductive material. If the material has a uniform resistivity (ρ) and a thickness (t), its resistance measured across opposite sides of the square would be R = ρ/t. Since the sides of the square have length L, the resistance is R = ρL/t * L/L = ρ/t * (L/L). The term L/L represents the aspect ratio of the square, which is 1. Therefore, R = ρ/t. The term ρ/t is defined as the surface resistance, R_s.

Surface resistance is useful because it is independent of the actual dimensions of the square piece of material, making it a convenient way to characterize the conductivity of thin films or coatings. A lower surface resistance indicates a more conductive material or coating, allowing current to flow more easily. Conversely, a higher surface resistance implies greater opposition to current flow. This parameter is important in applications such as antistatic coatings, electromagnetic shielding, and the fabrication of electronic components.