Speed of Light?

You can actually calculate the speed from just the physical parameters of the cable; spacing of conductors, materials, etc.

It is very common to measure the delay of a signal through some circuit. If you know the length of the circuit and the time of the delay it is easy to figure the speed.

example: Get a length of the cable with the output hooked to an oscilloscope. Inject a pulse into one end of the cable that also triggers the scope with a very short lead. Measure the time it takes for the pulse to get to the output of the cable relative to the trigger. Do the math.

My area of expertise is not in measuring such delays but I suppose there is test equipment specifically designed to do it. Google "transmission lines" for more info.

I just heard a story on the radio about scientists 'freezing light'. OK, does not help you here but this was so cool. They shot a light pulse into a "frozen atom cloud" and even moved the cloud and heated it, and the light actually continued from its new location. They considered the light to be 'stopped' and said it was actually slowed to about 15mph. This will someday be of use, but for now it's just one of the most facinating things I have ever heard. Sorry if I waisted your time not giving you an answer, but your question reminded me of this report and it kinda blows my mind.

In my electrical transient analysis class, we did it the way Herman describes.

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