Electrical Resistance. Concept, formula and types

Factors of electrical resistance

Electrical resistance depends on several factors, such as the type of material, its length, its cross-sectional area and its temperature. Materials that exhibit high resistivity, such as tungsten or nichrome (nickel-chromium alloy), are commonly used in the manufacture of resistors.

Formula of electrical resistance. Ohm’s law

The formula for electrical resistance is obtained from Ohm’s law, which states that the current (I) flowing through a conductor is directly proportional to the voltage (V) applied and inversely proportional to the resistance (R) of the conductor. The relationship is expressed by the formula:

I = V / R

Where

I is the current in amperes (A)

V is the voltage in volts (V)

R is the resistance in ohms (Ω)

Applications of electrical resistance

Resistors are used in a wide variety of electrical and electronic applications to limit current, control power and divide voltage. They are also used in circuits to protect sensitive components by limiting the amount of current flowing through them.

It is important to note that resistors have a limited capacity to dissipate energy in the form of heat. If their capacity is exceeded, they can be damaged or even burned out. Therefore, it is essential to select a suitable resistor for the specific application and to consider the maximum power it can dissipate without overheating.

Types of electrical resistance

There are different types of resistors, such as fixed resistors and variable resistors (potentiometers and rheostats), which allow their resistance value to be adjusted. There are also special resistors, such as temperature-sensitive resistors (thermistors) and light-dependent resistors (photocells or LDRs).