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A G R E AT E R M E A S U R E O F C O N F I D E N C E
Problem: Reading Drift
in Low Resistance
Measurements
Probable Cause: ity. Apply the test current and measure the circuit temperature during the meas-
Thermoelectric Voltages the voltage. Then reverse the polarity of urement cycle will cause changes in the
Thermoelectric voltages are the most the test current and measure the voltage thermal EMFs that will not be completely
common cause of reading drift in low re- again. Add the two voltage measure- cancelled, and some error will result.
sistance measurements. They are caused by ments and divide the result by two. This
differences in temperature between different completely cancels the thermal EMF in B. Offset Compensation Technique--Make
parts of the measurement circuit. the measurement. two voltage measurements, one with the
test current enabled, the other with the
Remedies This method requires a low noise voltme- test current disabled. Subtract the results
A. Current