Need to know how to calculate series, parallel and combined series and parallel circuit resistance? If you don't want to burn your circuit board, you should know! This article will show you how in just a few easy steps. Before reading it, understand that resistance doesn't really have an input and an output. The use of the words input and output is only a figure of speech to help beginners understand the concept of circuits.
Step
Method 1 of 3: Series Resistance
Step 1. What is it?
Series resistance is simply connecting the output of one resistor to the input of another resistor in a circuit. Each additional resistor added in the circuit is added to the total resistance of the circuit.
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The formula for calculating the total resistance n resistors in a series circuit is:
Rtot = R1 + R2 + …. R
So, all the series resistors just add up. For example, find the total resistance of the figure below
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In this example,
R1 = 100 and R2 = 300Ω in series. Rtot = 100 + 300 = 400
Method 2 of 3: Parallel Barriers
Step 1. What is it?
Parallel resistance is when the inputs of two or more resistors are connected, and the outputs of those resistors are connected.
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The formula for stringing n resistors in parallel is:
Rtot = 1/{(1/R1)+(1/R2)+(1/R3)..+(1/R )}
- Here is an example. Known R1 = 20, R2 = 30, and R3 = 30.
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The total resistance for 3 resistors in parallel is:
Req = 1/{(1/20)+(1/30)+(1/30)}
= 1/{(3/60)+(2/60)+(2/60)}
= 1/(7/60)=60/7 = approximately 8.57.
Method 3 of 3: Series and Parallel Combination Circuits
Step 1. What is it
A combination circuit is a combination of any series and parallel circuits that are connected in a single circuit. Try to find the total resistance of the following circuit.
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We look at the resistor R1 and R2 connected in series. So, the total resistance (we call it Rs) is:
Rs = R1 + R2 = 100 + 300 = 400.
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Next, we look at the resistor R3 and R4 connected in parallel. So, the total resistance (we call it Rp1) is:
Rp1 = 1/{(1/20)+(1/20)} = 1/(2/20)= 20/2 = 10
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Then, we see that the resistor R5 and R6 also connected in parallel. So, the total resistance (we call it Rp2) is:
Rp2 = 1/{(1/40)+(1/10)} = 1/(5/40) = 40/5 = 8
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So now we have a circuit with resistor Rs, Rp1, Rp2 and R7 connected in series. These resistances can be summed to get the total resistance Rtot from the initial sequence given to us.
Rtot = 400 + 20 + 8 = 428.
Some Facts
- Understand the obstacles. Any material that can produce an electric current has a resistivity, which is the resistance of a material to an electric current.
- Resistance is measured in units ohm. The symbol used for ohms is.
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Different materials have different resistance properties.
- For example, copper, has a resistivity of 0.0000017(Ω/cm3)
- Ceramic has a resistivity of about 1014(Ω/cm3)
- The larger the number, the greater the resistance to electric current. As you can see, copper which is usually used in electrical circuits, has a low resistivity. Ceramics, on the other hand, are highly resistive, making them good insulators.
- The way you assemble the resistors will make a huge difference to the overall performance of the electrical circuit.
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V=IR. This is Ohm's law, defined by Georg Ohm in the early 1800s. If you know the two variables of this equation, you can easily calculate the third variable.
- V=IR: Voltage (V) is the product of current (I) * resistance (R).
- I=V/R: Current is the product of the division of voltage (V) resistance (R).
- R=V/I: Resistance is the product of the division of voltage (V) current (I).
Tips
- Keep in mind that when resistors are arranged in parallel, there are many paths leading to the end of the circuit, so the total resistance will be less than each path. When resistors are connected in series, current flows through each resistor, so each resistor is added up to find the total resistance in series.
- The total resistance (Rtot) is always less than the smallest resistance of a parallel circuit; the total resistance is always greater than the greatest resistance of a series circuit.
