Errors in Low Current Measurements (2)

One of the most common causes of error when measuring low currents (<1nA) is offset current, which can come from the test setup or the measuring instrument.

Potential Cause:Meter Bias Current

Ammeters have some small current that flows when the input is open.

Remedies

Choose an electrometer or picoammeter to minimize meter bias current. Meter bias currents can be greatly reduced by enabling the instrument’s Current Suppress feature with the input terminals disconnected and the Zero Check switch open.