Pulse techniques can be used to
prevent internal heating. In this case the current is turned on for a few milliseconds,
the voltage measured and then turned off for, say, a second. Figure 12.13a
shows the simplest connection to the RTD with just two leads, the meter being
connected to the current supply leads. The resistance of long leads between the
detector and the resistor contribute to measurement error, as the meter is measuring
the voltage drop across the current lead resistance and junctions as well
as the RTD.