Precision measurement

Keithley Instruments  has published an informative e‑handbook titled “Making Precision Low Current and High Resistance Measurements.” This is available to download free on their website!

Topics covered

The e-handbook covers several topics crucial to ensuring low current measurement accuracy: • Measurement circuit • Leakage currents and guarding • Noise and source resistance • Zero drift • Generated currents • Overload protection • AC interference and damping • Using a coulombmeter to measure low current

Topics addressed in the e-handbook related to high resistance measurements include: • Constant-voltage method • Constant-current method • Guarding • Settling time

In addition to these topics, the e-handbook provides two measurement applications examples: avalanche photodiode reverse bias current measurements and voltage coefficient testing of high ohmic value resistors. A useful glossary of low-level measurement terminology and a guide to selecting instruments suitable for low current and high resistance measurements, such as ammeters , electrometers , and ohmmeters , are included. In addition, links are provided to a variety of webinars, white papers, and application notes relevant to each topic area.