circuit with a lossless impedance Z, three
resistors, and an ideal current source, is shown. We assume
that the resistor Rh has temperature Th, the resistor Rm
has temperature Tm, and the resistor Ra has no temperature.
The Johnson-Nyquist noise [15], [16] in the resistors Rh and
Rm will “heat up” the impedance Z. The resistance Rm is
the resistance of a passive (voltage) measurement device.
Its noise will add heat to the circuit and give measurement