Table 1-6 Current Measurement Accuracy Limits - Keithley 2425 Service Manual

Model 2425 Service Manual
4.
NOTE
5.
6.
Table 1-6
Current measurement accuracy limits
Model 2425 source
and measure range
10μA
100μA
1mA
10mA
100mA
1A
3A
1
Measure range coupled to source range when simultaneously sourcing and measuring current.
2
As measured by precision digital multimeter. Use closest possible value, and modify reading limits
accordingly if necessary.
3
Current calculated as follows: I = V/R, where V is the DMM voltage reading, and R is the
characterized value of the 1Ω resistor.
Verify measurement current accuracy for the 3A range as follows:
• Select the 3A source range.
• Set the Model 2425 source output to the correct 3A value as measured by the digital
multimeter.
• Note the DMM voltage reading, and then calculate the current from the voltage read-
ing and characterized 1Ω resistance value as I = V/R, where V is the DMM voltage
reading and R is the characterized resistance value.
• Verify that the Model 2425 current reading is within the 3A limits given in Table 1-
6.
It may not be possible to set the current source to the specified 3A value. Use the
closest possible setting, and modify reading limits accordingly.
Repeat the procedure for a negative 3A current.
Repeat the procedure using the rear panel INPUT/OUTPUT jacks. Be sure to select
the rear panel jacks with the front panel TERMINALS key.
Source current
1
10.00000μA
100.000μA
1.00000mA
10.0000mA
100.000mA
1.00000A
3.00000A
Performance Verification
Model 2425 current reading lim-
its (1 year, 18°C to 28°C)
2
9.9966 to 10.0034μA
99.969 to 100.031μA
0.99967 to 1.00033mA
9.9959 to 10.0041mA
99.939 to 100.061mA
0.99928 to 1.00072A
2.99673 to 3.00327A
1-17
3