Lei de Ohm

Resistors, often made from metallic alloys or carbon compounds, model a material's current-resisting behavior.

Ohm's law states that the voltage across a resistor is directly proportional to the current flowing through it, with the constant of proportionality known as resistance.

Resistance, measured in ohms, indicates the ability of a material to resist the flow of electric current.

It is directly proportional to the length and inversely proportional to the cross-sectional area of the material. The proportionality constant, resistivity, varies among materials.

Conductors have low resistivities, while insulators have high resistivities.

Linear resistors obey Ohm's law, with a linear relationship between their current and voltage, while non-linear resistors do not obey this.

A short circuit has zero resistance and voltage and can carry any current. In contrast, an open circuit has infinite resistance, zero current, and unrestricted voltage.

The reciprocal of resistance, known as conductance, measures how well an element conducts electric current.

It is measured in Siemens, with one Siemens equal to one ampere per volt.