In short
In a series circuit components are joined end-to-end so the same current flows through all of them; in a parallel circuit components are joined across common points so the same voltage appears across each branch.
Series Circuit vs Parallel Circuit - Comparison Table
| Basis | Series Circuit | Parallel Circuit |
|---|---|---|
| Arrangement | Single path (end to end) | Multiple branches |
| Current | Same through all | Divides among branches |
| Voltage | Divides across components | Same across each branch |
| Total resistance | R = R₁ + R₂ + … | 1/R = 1/R₁ + 1/R₂ + … |
| If one fails | Whole circuit breaks | Others keep working |
Want to understand this fully? Read the Physics notes on this chapter.