Listrik Dinamis • Part 3: Rangkaian Resistor Jembatan Wheatstone

Introduction

This tutorial provides a comprehensive guide on Wheatstone Bridge circuits, a fundamental concept in direct current (DC) electricity. It includes explanations of the circuit's operation, how to calculate equivalent resistance, and practical examples to reinforce learning. This guide is a continuation of a series on electric circuits, so familiarity with previous parts is beneficial.

Step 1: Understanding the Wheatstone Bridge Circuit

• The Wheatstone Bridge is a circuit used to measure unknown electrical resistances.
• It consists of four resistors arranged in a diamond shape with a voltage source connected across two opposite points and a galvanometer (or measuring device) connected across the other two points.
• Key components:
  • R1, R2: Known resistances.
  • R3: An unknown resistance.
  • R4: A variable resistor or the second known resistance.

Step 2: Setting Up the Circuit

• Connect the resistors in the following configuration:
  • Connect R1 and R2 in series.
  • Connect R3 and R4 in series.
  • Connect the series combinations across the voltage source.
  • Attach the galvanometer between the junction of R1 and R2 and the junction of R3 and R4.

Step 3: Applying the Balance Condition

• For the bridge to be in balance (no current flows through the galvanometer):
  • The ratio of the resistances must be equal:
    • ( \frac{R1}{R2} = \frac{R3}{R4} )
• This balance condition allows for the calculation of unknown resistance.

Step 4: Example Problem 1 - Equal Opposite Resistors

• Given:
  • R1 = 100Ω
  • R2 = 100Ω
• To find R3 when R4 is also 100Ω:
  • Using the balance condition:
    • ( R3 = R4 )
    • Therefore, ( R3 = 100Ω )

Step 5: Example Problem 2 - Unequal Opposite Resistors

• Given:
  • R1 = 150Ω
  • R2 = 50Ω
• If R4 is 100Ω, find R3:
  • Using the balance condition:
    • ( \frac{150}{50} = \frac{R3}{100} )
    • Cross-multiply and solve for R3:
      • ( R3 = 300Ω )

Step 6: Example Problem 3 - Finding an Unknown Resistance

• Given:
  • R1 = 200Ω
  • R2 = 100Ω
  • R3 = X (unknown)
  • R4 = 50Ω
• To find X when the bridge is balanced:
  • Set up the equation:
    • ( \frac{200}{100} = \frac{X}{50} )
    • Solve for X:
      • ( X = 100Ω )

Conclusion

The Wheatstone Bridge is a valuable tool for measuring unknown resistances in electrical circuits. Understanding its setup and the balance condition is crucial for solving practical problems. For further study, consider exploring additional topics in direct current circuits and their applications. Remember to review previous parts of the series for a more comprehensive understanding of the fundamentals.