110 – Kirchhoff law

This laboratory activity introduces students to Kirchhoff’s Current Law (KCL) and Kirchhoff’s Voltage Law (KVL) through hands-on experimentation with series and parallel circuits. By constructing circuits, measuring electrical quantities, and analyzing data, students will validate these fundamental principles of circuit theory.

Educational Goals

  • Understanding Kirchhoff’s Laws
    • Students will apply KCL (the sum of currents entering a junction equals the sum leaving) and KVL (the sum of voltage drops in a closed loop equals the supply voltage) to analyze series and parallel circuits.
  • Developing Circuit Analysis Skills
    • Through precise assembly of circuits and use of multimeters, students will measure current intensity and voltage drops across resistors, enhancing their technical proficiency.
  • Connecting Theory to Practice
    • By comparing theoretical predictions (e.g., in series) with experimental results, students will verify the conservation principles underlying Kirchhoff’s Laws.
  • Enhancing Analytical Thinking
    • Students will evaluate discrepancies between calculated and measured values, identifying sources of error such as resistor tolerances or measurement inaccuracies.
  • Promoting Collaboration
    • Working in groups, students will distribute roles in circuit assembly, data collection, and analysis, fostering teamwork and communication.
  • Emphasizing Safety Protocols
    • Students will follow safety guidelines to prevent electrical hazards, including proper power supply settings and insulated tool handling.

Protocol

  1. Set up a series circuit containing the 3 resistors.
  2. Turn on the power supply and set it to 12V.
  3. Measure the current intensity at the output of each resistor.
  4. Measure the intensity of the current at the source.
  5. Measure the voltage across each resistor.
  6. Measure the voltage at the source.
  7. Save the circuit diagram and disassemble it.
  8. Set up a parallel circuit containing the 3 resistors.
  9. Repeat steps 2 to 7.

Anticipated Outcomes

Series Circuit Analysis

  • Current Measurements: Students will observe identical current values at all points in the series circuit, validating KCL.

  • Voltage Measurements: The sum of voltage drops across resistors () will equal the source voltage (12V), confirming KVL.

Parallel Circuit Analysis

  • Current Measurements: The total current from the source will equal the sum of currents through individual resistors, upholding KCL.

  • Voltage Measurements: Identical voltage across all parallel resistors will align with KVL predictions.

Calculations

  • Students will compute total resistance () for both circuits and compare theoretical values (e.g., ) with experimental results derived from .

Summary of Assignment by Grade Range

Grades 9-10
Focus: Foundational understanding of circuit behavior and Kirchhoff’s Laws.

  • Students will assemble circuits, measure current and voltage, and recognize patterns (e.g., equal current in series, equal voltage in parallel).

  • Emphasis on qualitative analysis and basic calculations.

Expected Outcomes:

  • Ability to distinguish between series and parallel configurations.

  • Introductory proficiency in using multimeters and interpreting data.

Grades 11-12
Focus: Advanced quantitative analysis and critical evaluation.

  • Students will calculate total resistance, power dissipation, and percent error between theoretical and experimental results.

  • Detailed lab reports will include error analysis (e.g., impact of non-ideal resistors or instrument precision).

Expected Outcomes:

  • Mastery of Kirchhoff’s Laws in complex scenarios.

  • Competence in troubleshooting circuits and refining experimental methods.

Laboratory essentials

Instruments

Breadboard

3 x resistors

Wires

Multimeter

Power supply

Products

 

 

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