Dear Bob: It was with initial interest (eyes resting on the large-font title), then mounting dismay that I engaged in the misfortune of reading your article "What's All This Input Impedance Stuff, Anyhow?"* Being familiar with the Scriptures, it is quite clear you are parodying a portion of the ministry of Jesus Christ (while He was on Earth) to demonstrate an electronics principle. As a practicing Christian, I feel the parody, however educational in technical content, was wrong to do, simply wrong. (I must say, this does not look like parody but a parable. Surely Jesus did not have any patent or copyright on the use of PARABLES. Surely He was a great teacher when he used parables. /rap)
Having met you at a seminar and having been an admirer of your intelligence and your ability to dispense knowledge on heady subjects in accessible form, I'm ashamed and embarrassed for you. I don't like reading religious parodies. (I do not do PARODY on the Christian religion, or on ANY OTHER religion. I respect all religions. /rap) And I'm sure others don't either. Stick to the science and discourse we all love and appreciate you for and leave the Holy Bible out of that. I refuse to think you would consciously blaspheme on purpose. What one person considers light humor can nonetheless be considered blasphemy by others. Please be careful.
Dear Bob: On my master's thesis, back in 1966, I used a PACE analog computer with a 100-V dc swing. Was this machine equipped with K2s? (I am sure NOT. PACE had its own designs for amplifiers. /rap) On the tolerance problem with the K2-XA, let me take a shot. I would deeply distrust the neons, operating in the lower-than-mA range.
Urs Meyer (via e-mail)
Pease: Well, you might be skeptical, but we never had any problems with the neons! Never! Even after 40 years, my K2-Ws and -XAs are still working fine. What unreliability mode would you expect? Actually, we mostly used an improved NE-2--not sure if it was the NE-14--that had a dot of radioactive paint on the outside to help make sure it would light up. Consequently, the Navy would not let K2-Ws onto submarines. We made the K2-WJs (mil version) with zener level-changers that were more expensive, but not radioactive.
Dear Bob: I think that you and Martin Williams are right with your theory about card readers (electronic design, Feb. 16, p. 22). I would only add as follows: Many of these old types of readers do not reliably read my Discover card, too. Another trick, in addition to the one described in the article, is to swipe the card much faster. (In some cases this might work. But in the cases that are helped by adding a plastic layer, the signal is already too strong. And the thin plastic has the useful task of making the signal weaker. /rap) This will increase the frequency of the magnetic modulation and the amplitude of the head output, giving a "crispier" electrical signal for the reader circuitry to work with. Of course, there always is the best trick up one's sleeve--to order a replacement card.
Al Belotserkovskiy (via e-mail),
Pease: Recently, I was trying to check into a hotel room. I inserted the plastic "key" at a normal rate. It would not work. I tried it faster and slower. That didn't work. Finally, my wife tried it very slowly, and it finally worked.
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*electronic design, Sept. 6, p. 20.