Do you need to learn how to calculate series, parallel, and network resistor associations that combine the two types? If you don't want to burn your circuit board, you need to know how! This article will show you how to do this in just a few steps. Before starting, it is worth remembering that the use of "input" and "output" in the manuals on the subject is just a picture of speech to help novices understand the concepts of connection between resistors. But actually they don't really have an "in" and an "out".
Steps
Method 1 of 3: Series Resistor Associations
Step 1. Understand what this means
The association of resistors in series consists of connecting the "output" of one resistor to the "input" of another in a circuit. Each additional resistor placed in a circuit adds up to the total resistance of that circuit.

The formula for calculating a total of n resistors connected in series is:
R_{eq} = R_{1} + R_{2} + …. R
That is, the resistance values of the resistors connected in series are simply added together. For example, if we were to find the equivalent resistance in the image below

In this example, R_{1} = 100 Ω and R_{2} = 300Ω are connected in series. R_{eq} = 100 Ω + 300 Ω = 400 Ω
Method 2 of 3: Associating Resistors in Parallel
Step 1. What is it
Parallel resistor association is when the "inputs" of 2 or more resistors are linked together, and the "outputs" of the resistors are linked together.

The equation for a total of n resistors in parallel is:
R_{eq} = 1/{(1/R_{1})+(1/R_{2})+(1/R_{3}..+(1/R)}

Let's look at the following example. Data R_{1} = 20 Ω, R_{2} = 30 Ω and R_{3} = 30 Ω.

The total equivalent resistance for the 3 resistors in parallel is:
R_{eq} = 1/{(1/20)+(1/30)+(1/30)}
= 1/{(3/60)+(2/60)+(2/60)}
= 1/(7/60)=60/7 Ω = approximately 8.57 Ω.
Method 3 of 3: Circuits Combining Series and Parallel Resistor Associations
Step 1. What is it
A combined network is any combination of series and parallel circuits connected to form socalled "parallel equivalent resistors". Check out the example below.

We can see that resistors R_{1} and R_{2} are connected in series. So their equivalent resistance (let's highlight it using R_{s}) is as follows:
R_{s} = R_{1} + R_{2} = 100 Ω + 300 Ω = 400 Ω.

Next, we can see that resistors R_{3} and R_{4} are connected in parallel. So their equivalent resistance (let's highlight it using R_{p1}) is as follows:
R_{p1} = 1/{(1/20)+(1/20)} = 1/(2/20) = 20/2 = 10 Ω

So, we can conclude that resistors R_{5} and R_{6} are also connected in parallel. So their equivalent resistance (let's highlight it using R_{p2}) is as follows:
R_{p2} = 1/{(1/40)+(1/10)} = 1/(5/40) = 40/5 = 8 Ω

Now we have a circuit with resistors R_{s}, R_{p1}, R_{p2} and R_{7} connected in series. Henceforth, they can be added together to obtain the equivalent resistance R_{7} of the network we had at the beginning of the process.
R_{eq} = 400 Ω + 20Ω + 8 Ω = 428 Ω.
Interesting facts
 Understand the resistance. Any material that conducts electrical current has resistivity, which is the resistance of a material to electrical current.
 Resistance is measured in ohms. The symbol used for this measurement is Ω.
 Strength properties vary by material.
 Copper, for example, has a resistivity of 0.0000017 (Ωcm).
 Ceramics, on the other hand, have a resistivity of around 10 ^{14} (Ωcm).
 The higher the number, the greater the resistance to electrical current. You can see that copper, which is commonly used in electrical wiring, has a very low resistivity. Ceramic, on the other hand, is so resistive that it serves as an excellent insulator.
 How you join wires of varying resistances makes a big difference to the overall performance of a resistive network.
 V=IR. This is Ohm's law, defined by Georg Ohm in the early 1800s. If you know the value of at least two of the variables in this equation, you can easily calculate the value of the third.
 V=IR: Voltage (V) is the product of current (I) x resistance (R).
 I=V/R: Current is the quotient of voltage (V) ÷ resistance (R).
 R=V/I: Resistance is the quotient of voltage (V) current (I).
Tips
 Remember: when resistors are in parallel, there are many different paths to an end, so the total resistance will be less than each path. When the resistors are in series, current will have to travel through each resistor, so the individual resistors will be added together to give the total resistance for the series.
 The equivalent resistance (Req) is always less than the smallest contributor to a parallel circuit, and it is always greater than the largest contributor to a series circuit.