Basic Electrical & Electronics · Final Focused Module

KCL–KVL Laboratory
from theory to virtual wiring.

This final version contains only four required parts: resistor colour coding, animated KCL/KVL theory, equipment fundamentals, and a Tinkercad-style practical workspace.

Part 1

Resistor Colour Coding

Interactive 4-band and 5-band resistor calculator.

Mode

Band 1

Band 2

Multiplier

Tolerance

How to read the bands

Calculated resistance
1.0 kΩ ±5%

4-band: first two bands are digits, third is multiplier, fourth is tolerance.
5-band: first three bands are digits, fourth is multiplier, fifth is tolerance.

Part 2

KCL & KVL Theory with Animation

Charge conservation at a node and energy conservation around a closed loop.

KCL — Kirchhoff’s Current Law

The algebraic sum of all branch currents meeting at a junction is zero.

ΣI = 0 → I₁ − I₂ + I₃ − I₄ = 0

Example: 3 − 4 + 3 − 2 = 0. Current entering the node equals current leaving the node.

KVL — Kirchhoff’s Voltage Law

Around a closed loop, add all voltage rises and drops algebraically. Their sum is zero.

ΣV = 0 → +V_S − V_R1 − V_R2 − V_R3 = 0

Physical meaning: energy gained from the source is accounted for by voltage drops in the circuit elements.

Part 3

Equipment Fundamentals

Only the three laboratory instruments needed here: RPS, voltmeter and ammeter.

Regulated Power Supply RPS

Voltage knobsets required output voltage

Current knobsets a safe current limit

Actual load current ≈ V / R_eq

The current control is a current-limit setting; it does not force the selected current into the load.

Voltmeter V

Connect the voltmeter in parallel across the two nodes whose voltage is required.

V = potential at node 1 − potential at node 2

High internal resistance → draws very little current and minimally disturbs the circuit.

Ammeter A

Open the branch and insert the ammeter in series so the branch current passes through it.

I_branch = I_ammeter

Never connect an ammeter directly across the supply. Its very low internal resistance can behave like a short circuit.

Part 4

Tinkercad-Style Practical Workspace

Drag parts into one workbench, wire terminals and breadboard holes, then power and measure.