This refers to long lines. Is it inherent to electronics only or can be
demonstrated by gas pressure in a preumatic system, for example? I want to
know more about the problem. I'm asking for any good
demonstrations/materials describing the topic.
In a physics class one time, the teacher took long springs (like 'slinkys')
that had different stiffness rates. We spread them out over a table top and
hooked them up two at a time end to end (i.e. link one end of spring A to one
end of spring B making one continuous spring) using different combinations.
Then pull the combined springs until slightly taut and plucked one end. If
done right, you can see the differences in how much of the pulse is transferred
to the other spring. If I remember right, when the springs are the same almost
all of the pulse is transferred to the second spring. Other combinations
caused the pulse to reflect back with little of the pulse transferred to the
second spring.
Here, the spring rate or stiffness is analogous to impedance.
Right or wrong, I've always used this analogy when thinking about impedance
matching with regard to RF. When matched, more energy is transferred and less
is 'reflected' back to the source.
