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IEC 60283: DC Resistive Volt Ratio Boxes — The Reference Standard for Precision Voltage Ratio Measurement
From Standard Cells to Quantum Voltage: How Volt Ratio Boxes Achieve 0.0001% Ratio Accuracy
IEC 60283 specifies DC resistive volt ratio box requirements. Precision ratio boxes are calibration laboratory core equipment — dividing a known standard voltage by precise ratios (10:1, 100:1, 1,000:1) for calibrating voltmeters and potentiometers.
| Ratio | Accuracy Class | Typical Resistance (Input Z) | Application |
|---|---|---|---|
| 10:1 | 0.001–0.01% | 100kΩ/10kΩ | General voltmeter calibration |
| 100:1 | 0.001–0.005% | 1MΩ/10kΩ | Precision DVM calibration |
| 1,000:1 | 0.0005–0.002% | 10MΩ/10kΩ | Standard cell comparison, quantum voltage |
Ratio accuracy:
Ratio = (R1+R2)/R2 (valid only when Z_load >> R2)
Error = TCR_mismatch × ΔT + self-heating + loading
Self-heating: P=I²R raises resistor temp → TCR drift
→ Applied voltage must be limited so P < 0.01 × P_ratedTN Lab — Precision voltage measurement begins with the accuracy of the voltage ratio.
