Kirchhoff’s Current Law (KCL): Visual Guide
Level 1: Understanding the flow of charge at circuit junctions.
🌊 What is KCL?
Kirchhoff’s Current Law (KCL) states that the total current entering a junction (or node) must exactly equal the total current leaving that junction. Charge cannot be created or destroyed—it just splits and merges.
📐 The Formula: ΣI_in = ΣI_out
In any node: Current In = Current Out
Entering (+)
Current flowing toward the junction.
Leaving (-)
Current flowing away from the junction.
🚀 Real-World Example
The Setup: A main wire carrying 10A splits into three parallel branches.
- Branch A takes 3A.
- Branch B takes 5A.
- How much current flows through Branch C?
- Calculation: 10A (Total In) – 3A (Branch A) – 5A (Branch B) = 2A
- Branch C must carry 2A to satisfy the law.
The River Analogy
Think of a circuit junction like a river fork. If 100 gallons of water per minute flow into a fork, and one branch takes 60 gallons, the other branch must take 40 gallons. Water (charge) doesn’t just vanish at the split!