Electronics · DC circuits / Principles and inquiry
Wheatstone bridge experiment guide
Adjust the variable resistor to find the balanced condition where galvanometer current is zero.
How does it work?
At balance R₁/R₂ = R₃/Rx and the middle nodes have equal potential.
Key relationship
R₁/R₂ = R₃/Rx · Ig = (Vl−Vr)/Rg
Try this investigation
- Adjust the variable resistor to find the balanced condition where galvanometer current is zero.
- Run and record each of the three baseline presets.
- Compare the changed variable and its result with the baseline records.
Interpreting your results
With 4 V at the left node and 4.5 V at the right, what is the sign of left-to-right galvanometer current?
Ig < 0
Assumptions and limitations
The source and resistors are ideal, with no contact resistance or galvanometer zero error. Experiment on screen; do not reproduce this with real power supplies, outlets or high voltage.