If you are to get the results that you desire – and require – from your circuit design projects, you will need to have a solid grasp of such concepts as series and parallel resistance calculations.
You will need to be able to carry out these calculations in order to determine total resistance, current flow, and voltage distribution in electrical circuits. This capability, in turn, will help you achieve the optimal efficiency and reliability in the systems that you create.
Couldn’t You Simply Use a Series and Parallel Resistance Calculator?
From time to time, you could, of course, use a reputable series and parallel resistance calculator – such as the one on the RS website – to speed up these calculations.
However, an ability to undertake manual calculations will be crucial too, not least for verifying the accuracy of whatever calculation tools you may use.
Below, then, we have set out some of the key things you need to know about series and parallel resistance calculations.
Let’s Introduce A Few Essential Concepts
Whether you are a “mere” hobbyist needing to grapple with series and parallel resistance calculations for your next project, or a serious aspiring engineer, you might find it useful for us to “set the ground”:
- Resistance (R) is, in the words of BBC Bitesize, “a measure of how difficult it is for current to flow”. Measured in ohms, it is an indicator of the degree to which a given component opposes the flow of electric current (and it is important to note that every component in a circuit has a resistance).
In their creation of a range of useful circuits, engineers connect components in electrical circuits either in series or in parallel:
- When resistors are in series, this means the resistors are placed along a single path, one after the other. So, the current through each resistor will be the same. To put it another way: the current will stay the same across all points in the series circuit.
- When resistors are in parallel, this means they are arranged with both ends of each resistor being connected to the same two points in a circuit. With this arrangement, the supply current is equal to the sum of the currents through each resistor.
So, What Are the Formulas for Calculating Series and Parallel Resistance?
- The parallel resistor formula is as follows: 1/R=1/R1 +1/R2 +…+1/Rn, where R is the equivalent parallel resistance, and R1 and R2 are the resistances of individual resistors numbered to n.
- The series resistor formula, meanwhile, is: **Formula: **R=R1 +R2 +…+Rn, where R is the equivalent series resistance, and R1 and R2 are the resistances of individual resistors numbered to n.
What Else Do You Need to Bear in Mind About Series and Parallel Resistance Calculations?
The foundational importance of series and parallel resistance calculations in circuit design – including for enabling accurate predictions of current and voltage – means it is well worth becoming well-versed in how to carry them out manually, instead of depending purely on calculators.
By beginning with simple circuits, and practising regularly to develop your capabilities and confidence, you, too, can become a master of this critical aspect of circuit design.
