What is guarding? How can I use guarding for my measurements? How does current leakage affect low current / high resistance measurements?
This video answers these questions by demonstrating how guarding with a picoammeter works and how it can improve measurement quality.
Measuring a high value resistor in a test fixture using a Keithley 6487 Picoammeter/Voltage Source, we can see how guarding impacts the measured resistance of a device under test. Guarding can be useful for anyone measuring high value resistances of components, insulators, PCBs, multi-pin connectors, and more.
For more information on improving your low level measurements, check out the Keithley Low Level Measurements Handbook.