Tagged measurement
2 pieces
- · 10 min read
Measure Precision Before You Set a Threshold
Photograph the same sample five times without touching anything and the derived value will differ across the five images. If your decision threshold is narrower than that spread, the decision is a coin toss with a number attached. Precision has to be measured before any cut-off is designed, using the repeatability and reproducibility vocabulary the clinical precision standards already provide, and where precision will not support a decision the honest output is a flag rather than a call.
- · 10 min read
Your Multimeter Cannot See Your Sleep Current
Current consumption in a well-designed low-power device spans several orders of magnitude across a duty cycle, from microamps asleep to tens of milliamps transmitting. A bench multimeter integrates over its own measurement window and is effectively blind across most of that range. The useful quantity is charge per event, not current, and the rule that saves the most time is this: if the meter says zero and the battery disagrees, the battery is right.