To build an electronic circuit different components are required, and resistor is one of them. In all electronic circuits they can be found very easily. That means it is one the most important components in electronics.

And if electrons are less there will be less amount of flow of electrons, that means less current will flow through the resistor. Electrons collide with ions which slow down the flow of electricity and lowers the current and produces heat. That heat is absorbed by the ceramic core because the ceramic works as a heat conductor and can handle thermal stress very well so that the desired resistance levels can be obtained and maintained across the resistor.

Formula of is Resistance: R =V/I

Where I= current,

V= voltage,

R=resistance

Above formula states that resistance is directly proportional to voltage, and resistance is inversely proportional to current. Which means if the current is held constant, an increase in voltage will result in an increase in resistance. Alternately, an increase in current while holding the voltage constant will result in a decrease in resistance.

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When resistors are connected in series the equivalent resistance (Req) is the sum of individual resistance of each resistor.

Req = R1 + R2 + R3 + ... + Rn

In a series circuit, the current across all resistors remains the same. But the voltage across each resistor in series is different. And the total voltage across the circuit is the sum of the voltages across all the resistors.

The equivalent resistance of resistors connected in parallel is always less than the smallest individual resistance present in the circuit.

1/Req = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn

In parallel circuit, resistors do not have the same current across each of them. The sum of current across each resistor adds up to the total current across circuit. But resistors in a parallel configuration have the same potential difference (voltage) across each of them.

Specific resistance or resistivity is a measure of how strongly a material can resist the electric current flow. In other words, it is defined as the resistance given by a material with a unit length and unit area of cross section to the electric current flow.

We know that-- Resistance of any conductor is directly proportional to its length
*i.e.*R ∝*l*. - Resistance of any conductor is inversely proportional to the area of cross section.

a = Area in meter square

Where ρ is known as

then SI unit of specific resistance is

If you want to calculate the value of a resistor it could be tricky but not that hard. The resistor color code is read from left to right as shown in the below image.

To calculate the value of a resistor it requires a resistor color code table as well.

The resistor shown below contains 4 color bands.

1st and 2nd band indicates digits ---- 2, 2

To know the digits, see the resistor color code table above. In which red color indicates 2 and again red indicates 2.

3rd band indicates multiplier which is brown. Look at the table brown color band has a multiplier of 10.

Now multiply the digits with the multiplier.

2, 2x10 = 22x10 = 220Ω

4th band represents tolerance of the resistor ---- ±5%.

Look at the table to know the tolerance, see gold color tolerance section which shows ±5%.

The resistor shown below contains 5 color bands.

1st, 2nd and 3rd band indicates digits ---- 1, 0, 2

4th band indicates the multiplier ---- 0.01

1, 0, 2x0.01 = 102x0.01 = 1.02Ω

5th band indicates the tolerance which is ± 5%.

The resistor shown below contains 6 color bands.

1st, 2nd and 3rd bands in the above resistors indicates digits ---- 1, 9, 6

4th band indicates multiplier ---- 10

1, 9, 6x 10 = 196x10Ω = 1960Ω or 1.9

5th band indicates tolerance ---- ± 1%

6th band indicates temperature coefficient ---- which is 50ppm (parts per million) for red color band.