Strain Gauge Calculator
A gauge factor 2 gauge at 1000 microstrain in a 5 V quarter bridge gives 2.4975 mV, from a 0.7 Ω change in its 350 Ω.
2.4975024975025 mV
Full answer, then cut to fewer decimals (not rounded):
- 2.4975024975025 mV
- 2.497502497502 mV
- 2.49750249750 mV
- 2.4975024975 mV
- 2.497502497 mV
- 2.49750249 mV
- 2.4975024 mV
- 2.497502 mV
- 2.49750 mV
- 2.4975 mV
- 2.497 mV
- 2.49 mV
- 2.4 mV
- Resistance change ΔR = GF ε R
- 0.7 Ω
- Relative change ΔR/R
- 0.2 %
- Output per volt of excitation
- 0.4995004995 mV/V
- Linear approximation V_ex GF ε / 4
- 2.5 mV
Step-by-step solution
- ΔR/R = GF × ε = 2 × 0.001 = 0.002
- Vₒᵤₜ = V_ex (GFε/4) ÷ (1 + GFε/2) = 2.497502498 mV
Strain Gauge Formula
ΔR/R = GF × ε
quarter bridge Vₒ ≈ V_ex GF ε / 4; half (bending) V_ex GF ε/2; full V_ex GF ε
Worked Example
A 350 Ω gauge, GF = 2, at 1000 µε in a quarter bridge with 5 V excitation:
- ΔR/R = GF × ε = 2 × 0.001 = 0.002
- Vₒᵤₜ = V_ex (GFε/4) ÷ (1 + GFε/2) = 2.497502498 mV
Relative change ΔR/R: 0.2 % · Output per volt of excitation: 0.4995004995 mV/V · Linear approximation V_ex GF ε / 4: 2.5 mV
GATE tip
Stress from a gauge reading is σ = Eε. With E = 200 GPa, 1000 µε is 200 MPa. Combine with Young’s modulus questions from strength of materials.
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Frequently asked questions
What is microstrain?
Strain × 10⁶. Steel at its yield point is around 1000–2000 µε, so bridge outputs are only a few millivolts.
Why use half or full bridges?
More active gauges multiply the output and cancel temperature effects and unwanted strains, such as axial load in a bending measurement.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Strain Gauge Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/strain-gauge-calculator/
IEEE
Scientific Converters, "Strain Gauge Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/strain-gauge-calculator/