Fluke 5790A, Operator'S Manual

Page: 55 / 220

Front Panel Operation
Connecting Sources to the 5790A
4
4-7
Table 4-3. Input Test Lead Summary
Input
Connector
Input Frequency
dc to 100 kHz 100 to 300 kHz
300 kHz to 1 MHz 1 to 30 MHz
INPUT 1 TYPE
"N"
Coax any Length Coax Up to 3 ft
Coax Up to 1 f.
N/A
INPUT 2
BINDING POSTS.
Twisted-pair or coax
any length Twisted-pair or coax
up to 3 Ft.
Twisted-pair or coax
up to 1 Ft
N/A
WIDEBAND
TYPE "N
RG-58/U, 3 Ft.
Table 4-4. Input Impedance Summary
Input Range Inputs 1 and 2 Wideband Input
1000V 500 k
Ω
N/A
700V 500 k
Ω
N/A
220V 50 k
Ω
N/A
70V 50 k
Ω
N/A
22V 50 k
Ω
N/A
7V 50 k
Ω
50
Ω
2.2V >10 M
Ω
50
Ω
700 mV >10 M
Ω
50
Ω
220 mV >10 M
Ω
50
Ω
70 mV >10 M
Ω
50
Ω
22 mV >10 M
Ω
50
Ω
7 mV >10 M
Ω
50
Ω
2.2 mV >10 M
Ω
50
Ω
4-10. Connecting the Guard and Ground Binding Posts
Note
The following information applies to INPUT 1, INPUT 2, and the SHUNT
input only. It does not apply to the WIDEBAND input. The Wideband
option is designed so that once you connect a coaxial cable, no other
connections are required.
Ground currents can occur if instruments are not connected properly, resulting in
annoying and often subtle measurement errors. In any system of measurement
instruments, the basic rule is that all instruments should be grounded at only one point. If
an instrument in the system has a grounded input or output, select it as the common earth
ground point for all the grounds in the system.
Otherwise, use the ac voltage source used in the system (if there is one) as the common
ground point for all the instruments.
For more information about grounding and guarding, refer to Grounding and Shielding
Techniques in Instrumentation, by Ralph Morrison, \C1977, John Wiley & Sons.