Ippo Matsushita - 1(NIT (KOSEN), Nagano College)

Thinking Socializing in the view of Electric Circuit Reflection
Ippo Matsushita (NIT (KOSEN), Nagano College)
Today I’m going to talk about, “reflection”. What do you imagine when you hear“reflection?” When I was around ten or eleven years old, I associated it with a mirror or
barrier which appeared in animations or movies. Now, however, I relate reflection to anelectric circuit.
There are several types of reflection. As far as I'm concerned, it is hard for mostpeople to imagine what kind of reflection is found in society. I would like to give yousome examples.
Today, the Internet has become so widespread that there is no one who is notbenefiting from it. Optical fibers are used for communication by relaying the internet tous. In optical fiber, when light passes through a cord made of plastic or glass, the light
does not leak out because the transparent core and the surrounding material aredifferent. The important thing here is the difference of refractive indices between thetwo materials. If the refractive indices are equal, it is the same as if the light is passing
through the same material like glass to glass or water to water, so the light is notreflected.
The next technology using reflection is TDR. TDR is a word that many of you may
have never heard before. Some of you may also associate it with Tokyo Disney Resort.
However, the TDR I am talking about is “Time Domain Reflectometry”, which is used toidentify where power lines have been cut by falling trees. Without this technique, weneed numerous people to waste a lot of time.
Why is it now possible to identify that place so easily? The reason is that theresistance of the broken part is completely different from the connected part. If you
apply a rapidly changing voltage, pulse waves will travel down the line and reflect atthe broken point, just like ripples on the water. By measuring the time from input until
the pulse returns, we can determine where the wire was cut.
Further development of TDR is used in more micro-sized circuits. This method canidentify what is there. When a tetragon pulse is an input, a resistor will produce thesame tetragon waveform, a capacitor will produce a waveform that falls once and rises
slowly, and a coil will produce a waveform that rises once and falls slowly. This makes it
possible to estimate the contents of a black box by inputting a pulse and analyzing thereflected waveform.
What is important here is that the reflection in electronic circuits is similar to thelight, and the difference in reflected waveform differs depending on what kind of object

Ippo Matsushita - 2(NIT (KOSEN), Nagano College)
it encounters.
In addition to the well-known meaning of reflection, reflection in the dictionary also
has the meaning of "a thought, idea, or opinion formed, or a remark made as a result ofmeditation. When you are interacting with someone, your own actions result in areflection from the other person. Relations between you and I are a repetition ofreflection. In the same manner as an electric circuit, reactions are different for each
person because their characteristics are not the same. So, you should analyze it andthink deeply about what is in their mind. Through this process, you can understandthem more deeply and strongly.
If you are majoring in technology and can understand the feelings of electric circuits
better than the feelings of people, like myself, why don't you try to imagine your social
relationships based on the reflections of electric circuits?