learn.howToCalculate
learn.whatIsHeading
The Wheatstone bridge is a circuit used to measure unknown electrical resistance by balancing two legs of a bridge circuit. R_unknown = R3 × (R2/R1).
Công thức
At balance: R1/R2 = R3/Rx — solve for unknown Rx
- At
- R3/Rx — solve for unknown Rx — R3/Rx — solve for unknown Rx
- R1
- R3/Rx — solve for unknown Rx — R3/Rx — solve for unknown Rx
- R2
- R3/Rx — solve for unknown Rx — R3/Rx — solve for unknown Rx
- R3
- R3 value — Variable used in the calculation
- Rx
- Rx value — Variable used in the calculation
Hướng dẫn từng bước
- 1Four resistors arranged in a diamond (bridge) configuration
- 2A galvanometer in the centre detects current imbalance
- 3At balance: R1/R2 = R3/Rx — solve for unknown Rx
Ví dụ có lời giải
đầu vào
R1=100Ω, R2=200Ω, R3=150Ω
Kết quả
Rx = 300Ω
Bridge balanced when R1/R2 = R3/Rx
Lỗi thường gặp cần tránh
- ✕Assuming the bridge must be exact — modern circuits use operational amplifiers for nulling
- ✕Ignoring lead resistance in precision measurements
Câu hỏi thường gặp
What is a Wheatstone bridge used for?
Precision measurement of resistance, strain gauges, temperature sensors (RTDs), and load cells.
What happens when the bridge is balanced?
No current flows through the galvanometer. The voltage across it is zero.
Sẵn sàng để tính toán? Dùng thử Máy tính Wheatstone miễn phí
Hãy tự mình thử →