# What is Resistance? How to use it

In this series we write about resistance and resistance color codes; Resistance in electrical circuits is the strain faced by the electric current passing through a conductor. It shows features similar to friction in mechanical systems. The unit of resistance is Ohm (Ω). In equations, the letter R is indicated. In electronic circuits, the symbol of resistance can be shown in 2 different ways:

## What Does Resistance Do? What is his mission?

Resistors use to keep the current at a certain value by limiting the current in electrical circuits. In addition, they prevent high current from passing over sensitive circuit elements and are also used to divide the supply voltage and current. Some different types of resistors (such as LDR, NTC, PTC) can act as passive sensors to control physical changes in the external environment. In addition, the resistances are used to heat up as the current value falls on them.

## Where is resistance used?

Resistances have different uses according to their variety. Resistance is present in almost all electronic circuits due to the tasks I mentioned above. However, other types of resistances are also used in different tasks according to their use. Adjusted resistors such as ponciometers are often used in circuits where we want to control the output signal, such as the dimmer circuit. LDR-type resistors act as sensors that act according to the light intensity falling on them; they are used in light-sensitive circuits. NTC-PTC thermists, on the other hand, act according to the heat applied to them, so they also act as a sensor and are used in heat sensitive circuits.

## Electrical Resistance and Self-Esteem

An extract is the unit length of an item and the amount of resistance shown by the section area. The extract varies according to the type of substance, it does not change according to the amount of the substance. Its unit is Ohm-meter (Ω.m) and is represented in equations by the letter ε (rho).

## What Does Resistance Do? What is his mission?

There are different uses according to their variety, they are present in almost all electronic circuits due to their duties, which I mentioned above. However, other types of resistances are also used in different tasks according to their use. Adjusted resistors such as ponciometers are often used in circuits where we want to control the output signal, such as the dimmer circuit. LDR-type resistors act as sensors that act according to the light intensity falling on them; they are used in light-sensitive circuits. NTC-PTC thermists, on the other hand, act according to the heat applied to them, so they also act as a sensor and are used in heat sensitive circuits.

## Ohm What is It?

The unit of resistance is Ohm. The relationship between current, voltage and resistance in electronic circuits is calculated by Ohm law. The Ohm law was found by the German physicist George Simon Ohm in 1827. This law is one of the basic laws of electricity. The current passing through the conductor between the two points in an electronic circuit is directly proportional to the potential difference on it and inversely proportional to the resistance it has.

## Resistance Calculation with Color Codes

There are usually 4 or 5 colored strips on the resistors. These strips indicate the value of resistance. 4 color strips refer to the following values from left to right:

Lane 1: First step

Lane 2: Step two

Lane 3: Multiplier coefficient

Lane 4: Tolerance

### Let's Try and Learn!

The first strip is brown. That means our first step is step 1. The second strip is black. According to the table, that means 0. The number we got is 10. When we look at step three, we see a red stripe. That's 10^2, that's 100. So we have resistance of 10 x 10^2 = 1000 Ohm. The last strip is gold. This color tells us that the resistance we have is produced with a margin of error of 5%. Our resistance can be 5% of the 1000 Ohm value, that is, 50 Ohm higher or lower resistance. If the resistance we had had five lanes, we'd have one more digit before the coefficient. Again, if we go from our 1 kOhm ± 5% sample, the colors of a 5-strip resistance with this value will be coffee-black-black-coffee-gold. Before I forget, the final color coefficients of 6-strip resistors indicate the temperature coefficient of resistance.

## Types of Resistance

There are types of resistance according to different parameters such as material type, sheath types, variable/constant.

### Carbon Resistors

Carbon mixture or carbon resistance is obtained by heating and melting carbon and resin in powder form. The carbon ratio in the mixture determines the value of resistance. They are produced in values from 1/4, 1/2, 1, 2, 3 watts / 1Ω to 22 MΩ according to their size. Specifies values from the lines on it. It is the most widely used type of resistance in hobby electronics.

### Smd (Surface Mounting) Resistance

It is used when designing circuits as it requires very little space and does not require holes in the circuit. There are types of cases such as 0201, 0402, 0604, 0805, 1206 and 2010. The numbers above indicate the resistance value. It usually carries a 3- or 4-digit number. The first digits indicate the number, the last digit multiplier, and the letter R indicates comma. For example 3300 = 330 × 10^0 = 330Ω, 201 = 20 × 10^1 = 200Ω, 3R3 = 3.3Ω)