Model 6487 Reference Manual
Applications Guide
G-17
Zero check on / off response
shows the transient that can be expected from input HI to LO during a change
in the zero check mode with no input current. The transition is similar for entering and
leaving zero check. For current ranges 2
μ
A and below, the magnitude of the response is
not as large, but similar in duration. As with range change transients, the zero check tran-
sient is presented through an internal impedance which will limit the resulting current
through the DUT (
). If there is an input current while in zero check, the input
voltage will depend on the current and the zero check input impedance for the specific
range.
Figure G-13
Zero check transient
Table G-2
Internal impedance for zero check transient
Range Zcheck
Transient
impedance
2mA,20mA
500
Ω
20
μ
A,200
μ
A
50k
Ω
200nA,2
μ
A
3.5M
Ω
2nA,20nA
11M
Ω
