Keithley 6487 Reference Manual page 319

Model 6487 Reference Manual
klqb
Figure G-10
Range change voltage transients
R
F
+
V Transient
-
Range being
changed to:
2mA, 20mA
20μA, 200μA
200nA, 2μA
2nA, 20nA
The current that can be inadvertently delivered to the DUT is limited by an
internal resistance. This internal resistance varies as the range is changed. For
example, manually up-ranging from 2
more than 10V/50k
by any impedance of the DUT.
HI
LO
R F
500Ω
50kΩ
5MΩ
500MΩ
μ
A to the 20
Ω μ
= 200 A to the DUT. This current will be further limited
Applications Guide
6487
Picoammeter
μ
A range can never deliver
G-13