Wheatstone Bridge & Strain Gauge Calculator
Calculate quarter-bridge differential output voltage, structural microstrain (με), gauge resistance change (ΔR), and mechanical stress in PSI and MPa.
Calculated Results
Frequently Asked Questions
What is a Wheatstone bridge and why is it used with strain gauges?
Invented by Samuel Christie and popularized by Sir Charles Wheatstone, the bridge network detects microscopic fractional resistance changes (ΔR < 0.1%) that would be unreadable with standard ohmmeters by converting ΔR into a proportional differential voltage.
What is the formula for a Quarter-Bridge strain gauge circuit?
For a balanced quarter bridge: Vout / Vin = (GF × epsilon) / 4. Therefore, strain epsilon = (4 × Vout) / (Vin × GF).
What is a Gauge Factor (GF)?
Gauge Factor is the ratio of relative electrical resistance change to mechanical strain: GF = (ΔR / R) / epsilon. Metallic foil strain gauges typically have a GF around 2.0 to 2.1.
How does Hooke's Law convert microstrain into stress?
Stress (force per unit area) is directly proportional to strain via Young's Modulus: Stress (PSI) = Strain (epsilon) × E. For structural steel, E = 30,000,000 PSI (30 Mpsi).