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12-4
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Section Topics
2308-900-01 Rev. A / July 2008
Section 12: Performance Verification
Model 2308 Portable Device Battery/Charger Simulator User’s Manual
Resistor considerations
The test resistors should be characterized using the lowest possible range and the 4-wire ohms
function of the DMM recommended in
Table 12-1
to measure the resistance values. Use the
measured resistance values to calculate the actual currents during the test procedures.
Verification limits
The verification limits stated in this section have been calculated using only the Model 2308
accuracy specifications, and they do not include test equipment uncertainty. If a particular
measurement falls outside the allowable range, recalculate new limits based both on Model 2308
specifications and corresponding test equipment specifications.
Example limits calculation
As an example of how verification limits are calculated, assume you are testing the unit using a
10 V output value. Using the voltage output accuracy specification of ±(0.05% of 3 mV
offset), the calculated output limits are:
Output limits = 10 V ± [(10 V X 0.05%) + 3 mV]
Output limits = 10 V ± (0.005 + 0.003)
Output limits = 10 V ± 0.008 V
Output limits = 9.992 V to 10.008 V
Performing the verification test procedures
Test summary
• DC voltage output accuracy
NOTE
The temperature coefficient and temperature change of the 1
Ω
resistor when
passing current at full load must be low enough so that the change in resistance
does not cause incorrect readings. This is summarized in the following equation:
Where: VOUT is the output voltage
R is the characterized value of the resistor
DR is the change in resistance caused by heating
NOTE
Check the complete product Specifications at
www.keithley.com
for updated
output limits.
V
OUT
R
R
Δ
+
(
)
-----------------------
25% of Model 2308 amps specification
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