I check that the "CURRENT LOOP" leads go inside the 454a host,Looks like a current transformer principle,And it can only test AC current, DC current does not work.
Of course the ESU current has always been of the high frequency AC type.
I have QA-ES -II and DNI/FLUKE 454a,I found that the display effect of 454a is the best, the actual visual experience of QE-ES II is not very good, because the displayed number is very small.Observe the power value or current value, need to look very carefully。
454a only responds to AC signals, QA-ES II responds to either AC or DC,Of course ESU has always been an AC signal.
So 454a is more like the principle of induction measurement, and QA-ES II is more like the principle of attenuator measurement---This is my actual feeling, may be wrong
