How to Wire Resistors in a Series & in Parallel
By Spanner Spencer
Resistors are an essential component in electronic circuits that provide controlled impedance to the voltage and current running through the circuit. Resistors can be wired in two different ways within a circuit: series or parallel. Both options have their own specific benefits and uses, and it is essential that the correct wiring option is selected for your circuit as the resistors behave differently in each configuration.
Trim one leg of your first resistor to approximately a quarter of an inch in length. Gauge the length required by the amount of space you have within the circuit, bearing in mind that enough of the leg must remain available for soldering to the next resistor.
Trim one leg of your second resistor to match that of the trimmed leg on your first resistor.
Align the two trimmed legs alongside each other in-between the bodies of the two resistors. Solder them together making a chain of two resistors in a straight line. The two resistors are now connected in series. If required, more resistors can be connected inline before applying the chain of series-connected resistors to your circuit.
Position the resistors to be connected in parallel alongside each other so all the legs are aligned and pointing in the same direction, resembling a rib cage or a picket fence.
Solder the bottom legs of each resistor together, and then trim them to an appropriate length for your circuit's requirement using the wire cutters. The legs can be twisted together before soldering if required.
Solder the top legs of each resistor together, and then trim them. The resistors are now wired in parallel and ready to be applied to your circuit.
- When connected in series, resistors provide an electrical impedance that is equal to the sum of all resistors connected one after the other. For example, two 100 Ohm resistors connected in series produce and impedance of 200 Ohms. This is a useful method for achieving a specific impedance from resistors that do not match your required value. However, the maximum current capability for each individual resistor must not be exceeded in a series circuit.
- A common colloquialism for a series configuration is "daisy chain," which helps to visualize how series-connected resistors are aligned with each other.
- When connected in a parallel configuration, the sum of the resistors' combined values is halved. For example, two 100 Ohm resistors connected in parallel produce an impedance of 50 Ohms. However, the parallel configuration is capable of carrying a greater current through low-wattage resistors, as the load is spread evenly between each component in the parallel configuration.
- Other electronic components, such as inductors, can also be connected in series or parallel, and their operational properties exhibit the same differences as described for resistors.
- Ensure there any circuits you are working on are disconnected from their power source before beginning.
Spanner Spencer has been writing since 2005 for a variety of print and online publications. Focusing on entertainment, gaming and technology, his work has been published by Eurogamer.net, "The Escapist," "GamesTM," "Retro Gamer," "Empire," "Total PC Gaming" "The Guardian," among others. Spencer is a qualified medical electronics engineer with a Business and Technology Education Council certificate in technical writing from Huddersfield Technical College.