Series v Parallel

Series Circuits

Definition: In a series circuit, components are connected end-to-end so that there is only one path for current to flow.

Characteristics:

  • Total Resistance (Rtotal) increases: Rtotal = R1 + R2 + R3 + …

  • Current (I) is the same through all components: Itotal = I1 = I2 = I3 = …

  • Voltage (V) is divided among components: Vtotal = V1 + V2 + V3 + …

  • Implications: If one component fails (e.g., a bulb burns out), the entire circuit stops working.

Parallel Circuits

  • Definition: In a parallel circuit, components are connected across common points or junctions, creating multiple paths for current to flow.

  • Characteristics:

    • Total Resistance (Rtotal) decreases: 1/Rtotal = 1/R1 + 1/R2 + 1/R3 + …

    • Voltage (V) is the same across all components: Vtotal = V1 = V2 = V3 = …

    • Current (I) is divided among components: Itotal = I1 + I2 + I3 + …

  • Implications: If one component fails, the other components continue to operate, providing an easier and safer alternative for many electrical devices.

Key Differences

Feature

Series Circuits

Parallel Circuits

Path for Current

Single path

Multiple paths

Total Resistance

Increases with each additional load

Decreases with each additional load

Current

Same throughout

Divided among branches

Voltage

Split across components

Same across each branch

Effect of Component Failure

Entire circuit stops working

Other components continue operating

Applications

  • Series circuits: Often used in string lights or for simple devices.

  • Parallel circuits: Common in household wiring where devices require the same voltage and must operate independently.