The Keysight / Agilent / HP 432A power meter is an automatic, self-balancing power meter for use with temperature compensated thermistor sensors. High efficiency and good radio frequency (RF) match are characteristics of the 478A and 8478B coaxial and 486 series (now discontinued) waveguide thermistor mounts that cover the frequency range 10 MHz to 40 GHz. Each thermistor mount contains data showing the calibration factor and effective efficiency at six frequencies, directly traceable to the U.S. National Institute of Standards and Technology (NIST) at those frequencies where NIST provides calibration service.Agilent 432A provides high accuracy over a wide temperature range. By measuring the output voltage of the Thermistor bridges and computing the corresponding power, even higher accuracy of ±0.2 percent ±0.5 micro W can be obtained. Accuracy can be maintained on even the most sensitive range because the error due to thermoelectric effect is reduced to a negligible level.