Online — In an online article at Test & Measurement World entitled “Test Ideas: Bias current modulation eliminates wiring errors”, author W. Stephen Woodward, Consultant, Chapel Hill NC, USA says:
Diodes make good temperature sensors because they are inexpensive, robust, stable, and sensitive, and they don???t need reference junctions. Diodes require an excitation current to produce a PN-junction voltage, which varies with temperature by ???2 mV/??C. The excitation current causes voltage drops in measurement wires because of a wire???s resistance. You need to compensate for those voltage drops so that the measurement will accurately represent the diode voltage.
The article then goes on to explain the solution and provide an op amp circuit that can solve the problem.
You can download a PDF version of the article by CLICKING HERE or visit the article online here: “Test Ideas: Bias current modulation eliminates wiring errors”,