[From Dag Forssell (930619 1230) Hans Blom 930619
I have been a control engineer for so long (25 years)...
...Now imagine an almost identical situation, where it is
the electrical power engineer's task to track the current and
voltage of those energy-rich 380.000 Volt overhead power lines on
his oscilloscope. What he needs is a tremendous power LOSS. The
components of his measurement system are non-ideal as well, and
therefore he too needs feedback. Where is the power gain now?
As a mere mechanical engineer, with limited understanding of
electronics and control, I am astounded that you offer this as a
serious proposition. Perhaps your oscilloscope is *powered* by the
380,000 volt line. I have never heard of one.
Any oscilloscope I have ever encountered works exactly like the HI
FI amplifier you describe and *requires* power. The oscilloscope is
plugged into the wall, or has a battery to draw on. Typically, The
signal from the 380,000 line is reduced by resistors (without
distortion) to a suitably low voltage and almost no amperage signal
to the oscilloscope input. From there it is AMPLIFIED to drive the
cathode ray tube that the human looks at.
Looking at the Niagara Falls is to me quite analogous. There is
(paraphrasing you) tremendous power LOSS between the energies in
the falling water and the vision in my brain. But there is
AMPLIFICATION between the small amont of light that falls on my
retina and the image I experience (internal to my nervous system),
powered by blood sugar and whatever else from food.
Fortunately for me, I don't have to deal with the full brunt of
Niagara, any more than the oscilloscope deals with 380,000 volts
and thousands of amperes.
Best, Dag