Before we can answer this question in more detail, we need to understand exactly what a resistor is? The resistance of a resistor is a property that opposes or resists the movement of electrons through it, which makes it necessary to use an external voltage for current flow. Electrons that circulate through a resistor or metallic conductor have a certain difficulty in free circulation, because the material resists their movement. The magnitude of the resistance to this flow depends on the length, cross-sectional area and material of which it is made.
Electrons in the form of electric current will better pass through the conductor, if its area is larger and its length is shorter. Then there is a connection between the shape of the conductor and its ability to pass electrons. This attitude is called "resistance." Resistance should not be confused with resistance.
The component that must have a resistance is called a resistor. Resistors are passive elements in an electrical circuit that absorb energy and convert this energy into heat. In addition, resistors are two-sided devices that can transfer current in both directions. To best describe the resistance of a resistor and, therefore, its characteristics, it is important to determine it using Ohm’s law.
In metal conductors and resistors, the current through it is proportional to the applied voltage on it, and for a resistor that is kept constant, doubling the voltage doubles the current and so on. Then the voltage on the conductive material is directly proportional to the flow of current through the material and the relationship between the voltage ( AT ) and current, ( I ), in which resistance, ( R ) is constant, called the proportionality constant.
This important connection between the three electrical units (volts, amps, and ohms) was first experimentally determined by Dr. Georg Simon Om in 1826 and is called the “Law”. The unit that measures resistance is called ohms (Greek Omega & # 39;). Ohm's law is the most fundamental law used in circuit analysis.
Using Ohm's law, it is easy to find the value of each electrical block V, I and R, knowing the values of the other two components. It is a simple formula that describes the voltage-current relationship for a resistor or any conductive material, and this definition is mathematically expressed as:
V = I * R , I = V / R , and R = V / I
There were: I - current, V - voltage, and R - resistance.
In its simplest form, Ohm’s law states that the current flowing through a resistor between two points is directly proportional to the voltage at two points and inversely proportional to the resistance between them. Therefore, if the electrical resistance of the conductor is one ohm, the applied voltage of one volt will lead to the flow of current of one amplifier. It is also obvious that according to this law of proportionality, the greater the resistance, the less current will flow for a given amount of applied voltage, since the ratio is always constant.
However, Ohm’s law applies only to “ohmic materials,” which are materials that obey Ohm’s law of proportionality, since not all materials follow this relationship V - I.
So now we understand what Ohm's Law is, we can say that the ratio between voltage and current in a resistor can be defined as: "voltage across resistance = resistance value multiplied by the current flowing through the resistance."
I hope that this short tutorial was useful for anyone who is new to the electronics world, either as an amateur or as a student who is trying to learn electronics.
