Series and Parallel Circuits

Understanding Series Circuits

A series circuit is a circuit in which all components are connected end-to-end, forming a single path for electricity.
The current is the same through each component in the series circuit because there’s only one pathway for all the charges to flow through.
The sum of the voltages across each component in the series circuit is equal to the total voltage supplied by the power source. This is known as Kirchoff’s Voltage Law.
If one component in a series circuit fails or is disconnected, then the entire circuit becomes open and no devices receive current.

Understanding Parallel Circuits

A parallel circuit is a circuit in which the components are arranged with their heads connected together, and their tails connected together.
Unlike a series circuit, a parallel circuit has multiple pathways for electricity to flow through. Each electrical device is hooked up to the power source individually.
In a parallel circuit, the voltage is the same across each component, but the current is divided among each pathway.
If one component in a parallel circuit fails or is disconnected, it does not affect the other components in the circuit. The remainder of the circuit continues to have the same voltage and can continue to operate normally.

Calculating Resistance in Series and Parallel Circuits

For a series circuit, the total resistance (R_total) is simply the sum of the resistances of each component: R_total = R1 + R2 +…+ Rn.
However, in a parallel circuit, the formula for total resistance is different. The reciprocals of the resistance of each component add up to the reciprocal of the total resistance: 1/R_total = 1/R1 + 1/R2 +…+ 1/Rn. Thus, the total resistance in a parallel circuit is always less than the resistance of any one branch.

Practical Applications and Considerations

Most home wiring is parallel to allow individual control of each electrical device, while many flashlights or simple electronics use series wiring.
The choice of series or parallel circuits depends on the desired effect. Series circuits are beneficial for devices like Christmas lights where if one bulb goes out, it’s clear that a replacement is needed. Parallel circuits are convenient in homes because they allow all devices to run independently of each other.
You should always consider the power requirements and the role of each component in your circuit design before deciding on the arrangement of the circuit components.