Carl Oppedahl's blog
Musings about office technology from an intellectual property lawyer
Route 66 is one of the most famous roads in the US. It originally ran from Chicago, Illinois, through Missouri, Kansas, Oklahoma, Texas, New Mexico, and Arizona before terminating in Santa Monica in Los Angeles County, California, covering a total of 2,448 miles (3,940 km). Established in 1926, by 1938 it became the first highway in the US to be paved along its entire length. Continue reading “Being on Route 66”
As many readers know, nearly all electrical power transmission lines are three-phase AC (alternating current). When you look up at one of the towers, you see three (or a multiple of three) transmission conductors. In the US there are are only a few direct-current (DC) transmission lines. One of them is called Path 27. I first read about Path 27 about seventeen years ago, when I was writing the patent application that became US patent number 8183714. Recently I was able to do something that I had wanted to do for a very long time — I visited one of the massive ground electrodes for Path 27. Continue reading “A pilgrimage to Path 27”
This photo shows a charging station in Baker, California. At left are twelve Electrify America supercharging spots. At right are forty Tesla charging spots. Behind this is a construction area where there will soon be fifty more Tesla charging spots. All of these charging spots are shaded by canopies made of, you guessed it, photovoltaic solar panels. The Tesla charging station also has battery storage. Continue reading “Supercharging station with lots of plugs”
Lewis Carroll is of course well known as the pen name for Charles Dodgson. And he is of course well known for having written two Alice books.
But he was a also a mathematician and devised many clever puzzles that involved math and deductive reasoning and probability. Here is one. Continue reading “What color is the counter?”
I have aways sort of vaguely assumed that at some point in my youth I must have sat in a class in which the teacher made a potato battery and used it to light up a light bulb. Recently I got it into my head that it might be interesting to reconstruct that old classroom demonstration. But events of the past few days, recounted in this blog article, make me think that the old classroom demonstration must have never actually happened. I must have just read about it in books and I must have sort of assumed that you could do, in real life, anything that is described in a book. After many false starts, I did eventually manage to light up a light with a potato battery. Continue reading “quantum physics and potato batteries”
Loyal readers will recall that recently I did a large number of test welds to measure welding currents generated by my new inexpensive stick welder (blog article). I had been using my smart phone to log real-time current measurements via Bluetooth from a clamp-on DC ammeter (blog article). Part way through the large number of test welds, I was astonished to see that my smart phone had powered itself down. I tapped the power button and coaxed the phone back to life and completed my current logging activities, and eventually figured out why the phone had so mysteriously and abruptly powered itself off. A tiny bit of hot steel from one of my test welds had flown several feet and had landed on the glass screen of the phone, and had melted a small crater in the glass. You can see the crater, which is less than one-fourth of a millimeter in diameter, in the photomicrograph above. After about a day, cracks had traveled from this crater across the full expanse of the glass. I realized I would need to learn how to replace the screen. This blog article describes it. Continue reading “Replacing a screen of a smart phone”
As we know, the “springing forward” of clocks for Daylight Saving Time happens at about 2AM. This “radio controlled” wristwatch does the DST adjustments automatically. I happened to be awake when it happened just now, and you can see a video recording of the automatic adjustment carried out by this wristwatch.
This blog article talks about using an automation controller to keep a server room from getting too hot. Continue reading “Cooling a server room”
The implicit promise made by the maker of an RCA cable is that its center conductor is shielded by its outer conductor. I have, however, been astonished in recent times to see that many RCA cables are not shielded at all. Continue reading “Shielded and yet not shielded”
It will be recalled (blog article) that I had recently started getting familiar with an inexpensive inverter welder. What became pretty clear early on is that the number in the display does not match the number of amperes of welding current delivered to the welding rod. Alert reader Dave posted a comment:
Can you accurately anticipate what amperage to expect given the readout on the machines as a ratio to the readings you have gotten on the ammeter? Perhaps this is an opportunity to do some more experimentation…
Prompted by alert reader Dave, I did some more measurements. Here are the results.