![Keithley 2701 Скачать руководство пользователя страница 439](http://html2.mh-extra.com/html/keithley/2701/2701_user-manual_3950600439.webp)
E-10
Measurement Considerations
Model 2701 User’s Manual
Meter loading
Loading of the voltage source by the Model 2701 becomes a consideration for high source
resistance values. As the source resistance increases, the error caused by meter loading
increases.
Figure E-5 shows the method used to determine the percent error due to meter loading.
The voltage source, V
S
, has a source resistance, R
S
, while the input resistance of the
Model 2701 is R
I
and the voltage measured by the nanovoltmeter is V
M
.
Figure E-5
Meter loading
The voltage actually measured by the meter is attenuated by the voltage divider action of
R
S
and R
I
, and it can be calculated as follows:
This relationship can be modified to directly compute for percent error:
From the above equation, it is obvious that the input resistance of the Model 2701 must be
at least 999 times the value of source resistance if loading error is to be kept to within
0.1%.
V
M
Measured
Voltage
R
S
R
I
V
S
Source
Voltage
+
–
V
M
V
S
R
L
R
I
R
S
+
-------------------
=
Percent error
100R
S
R
I
R
S
+
-------------------
=
2701-900-01.book Page 10 Wednesday, August 3, 2011 9:43 AM
Содержание 2701
Страница 344: ...12 CommonCommands 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 352: ...13 SCPISignalOriented MeasurementCommands 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 366: ...15 SCPIReferenceTables 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 393: ...A Specifications 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 399: ...B Model7700ConnectionGuide 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 410: ...C StatusandErrorMessages 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 417: ...D SignalProcessing SequenceandDataFlow 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 430: ...E MeasurementConsiderations 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Страница 450: ...G KE2700InstrumentDriver Examples 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...