Wheatstone Bridge Calculator Formula
Understand the math behind the wheatstone bridge calculator. Each variable explained with a worked example.
Formulas Used
Bridge Voltage
bridge_voltage = v_supply * (r3/(r1+r3) - r4/(r2+r4))Ratio R1/R3
ratio_left = r1/r3Ratio R2/R4
ratio_right = r2/r4Variables
| Variable | Description | Default |
|---|---|---|
v_supply | Supply Voltage(V) | 10 |
r1 | R1 (top-left)(Ω) | 1000 |
r2 | R2 (top-right)(Ω) | 2000 |
r3 | R3 (bottom-left)(Ω) | 1000 |
r4 | R4 (bottom-right)(Ω) | 2000 |
How It Works
Wheatstone Bridge Analysis
A Wheatstone bridge measures unknown resistance by balancing two divider legs.
Formula
V_bridge = V_s x [R3/(R1+R3) - R4/(R2+R4)]
Balanced when R1/R3 = R2/R4 (bridge voltage = 0).
Worked Example
10 V supply, R1=R3=1k, R2=R4=2k.
v_supply = 10r1 = 1000r2 = 2000r3 = 1000r4 = 2000
- 01Left: R3/(R1+R3) = 1000/2000 = 0.5
- 02Right: R4/(R2+R4) = 2000/4000 = 0.5
- 03V_bridge = 10 x (0.5 - 0.5) = 0 V (balanced)
Frequently Asked Questions
What does balanced mean?
Bridge voltage is zero and no current flows through the galvanometer.
What is it used for?
Precision resistance measurement, strain gauges, load cells, and temperature sensors.
Can bridge voltage be negative?
Yes, indicating reversed polarity compared to the assumed direction.
Ready to run the numbers?
Open Wheatstone Bridge Calculator