Power measurement is a fundamental requirement for evaluating electrical systems. While oscilloscopes are widely used for waveform observation, debugging, and noise analysis, they are not designed to deliver the precision necessary for reliable power analysis. Accurate measurement is essential when evaluating efficiency, verifying compliance, or ensuring product quality.
For Power Analysis Measurements using an oscilloscope, the setup usually involves:
- 8-channel oscilloscope
- 4 × high-voltage differential probes
- 4 × AC/DC current probes with dedicated power supplies
- PC and waveform analysis software
On the contrary, a HIOKI Power Analyzer, like the PW4001, simplifies the measurement setup:
- Measuring 4 systems of voltage + current = 4 power channels
- Direct high-voltage input without differential probes
- Safe and accurate current measurement via clamp-on sensors
- Real-time efficiency, power factor, harmonics, and energy display
- No post-processing required - just connect and measure
In the below table, you may find a short comparison for power measurement between a high end scope and a power analyzer:
| Features: | Resolution | Basic Power Accuracy | Basic Voltage Accuracy | Basic Accuracy of current probes | Phase accuracy |
| Oscilloscope | 12 to 14 bits | Not specified (approx. 5% of reading) | Approx ± 2% of reading | Approx. ±1% of reading | Often Unspecifed |
| Hioki PW4001 | 16 bits | ± 0.1% of reading*1 (basic ±0.03% of reading & sensor accuracy) | ± 0.03% of reading | ± 0.07% of reading *1 (depends on sensor model) | Auto Compensated |
With oscilloscope-level accuracy, differences below 5% might go undetected.
For applications like inverter efficiency, where 0.1% matters, the PW4001 is clearly superior.
When accuracy, compliance, and reproducibility are essential, so is the tool you use. Oscilloscopes are fantastic for waveform observation, noise tracing, and debugging. Advanced scopes in the market, like the Keysight HD3 series, have 14 bits of ADC and very low noise levels, improving power analysis measurements accuracy. But if you want reliable values of power, efficiency, harmonics, and energy, then the power analyzer is the necessary measurement instrument for this task
Please find below more information on HIOKI’s PW4001 and Keysight HD3.