Electronic Design

Bob's Mailbox

Dear Bob:
We routinely use stainless steel welding rod for crude shunts. It comes in a variety of diameters and we pick a size and length based on the "try-it-and-see" approach. We're not looking for exact calibrations, but rather a 50-mV signal at the desired current. We then monitor the signal, looking for a current change in the 25% range as a "lamp failure" indication. With the right flux, you can even solder copper wires onto the stainless rod for the sense points

Sounds reasonable to me! Thanks for the observations.—RAP

Dear Bob:
My investigation into potassium pills revealed that 99 mg of potassium equals 3% of the daily value needed and is the most common potency available. (That is the normal statement, but I find it incredible that 33 * 99 mg is normal and the "MDR." I never take that much in one day! /rap) It is important to read labels carefully to ascertain that the pills contain 99 mg of elemental potassium—whether it be gluconate, orotate, aspartate, or amino acid chelate. (The gluconate seems to take 550 mg per tablet to make 99 mg of potassium. I apologize for being imprecise in my column. See the Sept. 30 issue, p. 110. /rap)

I found an inexpensive source of potassium gluconate pills on the Internet at www.bioenergynutrients.com. I just ordered a supply of 2000 for $24.95 less 10%!

Not a bad price. Mine costs nearly twice that. But in terms of pennies per day, not a big deal! Thanks for hollering!—RAP

Dear Bob:
My engineer husband shoved your editorial at me. It's great. Doctors always say, "Listen closely to the history. It will give you the diagnosis 80% of the time." The history is what the patient tells the doctor. If the history is accurate, the diagnosis has a much better chance of being accurate. (I just heard of a study: When patients want to give a two-minute explanation of their problem and symptoms, the doctor typically interrupts several times in the first minute, and the second half of the symptoms is never recited. Ha! /rap)

Re: potassium and magnesium. In the hospital as a medical resident, I was taught to remember to give magnesium if someone was having trouble retaining the potassium that we had supplemented. This was especially a problem in people who (prior to hospitalization) had been getting most of their calories from alcohol. But it also was true for others without pristine fresh-vegetables-and-fruits diets. (I get a good bit of fresh veggies, as my wife has many excellent veggie recipes. On some treks, when I get to 10,000 ft, there are some veggies, but not a lot. Bringing magnesium pills up to high altitudes is a cheap fix. /rap)

In the "out-patient" realm that I now inhabit, doctors seldom mention magnesium. We don't have inexpensive and accurate blood tests for mild magnesium deficiencies, so we can look for a clinical diagnosis, such as reports of migraines, brief heart palpitations, and muscle cramps—including facial tics, abdominal or pelvic cramping, and charley horses. By examination, one may see tongue spasms, or see twitching when the cheek muscles are tapped. Note that some of these symptoms can also occur with deficiencies of potassium or calcium, or have other explanations. (Do most doctors know what to look for, in terms of clues pointing to mineral deficiencies? /rap)

It is good that you added the disclaimer about checking with one's doctor. People can ingest too much potassium. It is easy to check a blood level, though, to monitor this. Of course, anyone with kidney insufficiency needs to very closely coordinate their supplementation with their doctor, or they can get in trouble with potassium, magnesium, etc.

Re books: I agree with the Wilkerson recommendation. It's readable and usable. I have also enjoyed Advanced First Aid Afloat by Peter Eastman, MD. I don't know if it is still in print.

Most people don't get high-altitude sickness on boats, but the principle is the same: Travel in a "wilderness"—such as a large ocean—requires careful planning for first and second aid.—RAP

All for now. / Comments invited!
RAP / Robert A. Pease / Engineer
[email protected]—or:

Mail Stop D2597A
National Semiconductor
P.O. Box 58090
Santa Clara, CA 95052-8090

Note: I am a big fan of the word-processing software, "PC-Write Lite," originally sold by Quicksoft. It runs very nicely on MS DOS 3.1. And it keeps on ticking, even though Quicksoft and its successor "Starlite Software" are not doing business now. But a writer from Denmark asked me, "Where can I find a book, PC-Write Wizards Book, on advanced software options for PC-Write?" I searched all around, on and off the 'net. This book is not easy to find! Does anybody have a copy? If so, holler. Thanks. /rap

Note: Does anybody want to buy a Philbrick R-300 power supply, ±300 V dc at 300 mA, in very good running condition? There's a guy in Oshkosh who wants to sell one. It's just like the one I wrote about last January. It's ideal for powering up your very own (vacuum-tube) analog computer. Bidding starts at $25 plus $32 shipping. I'll bid that, and anybody who wants to outbid me can buy it. I don't really need two. /rap

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.