HP Clip-On D.C. Current Probe

[PRR]

HBP> I'm eager to test, calibrate and try out the clip-on current meter I've got.
HBP> an HP 428B

Electronics World, September 1964, pg 41
http://www.americanradiohistory.com/Electronic_World_Master_Page.htm

CLIP-ON D.C. CURRENT PROBE
By Arndt Bergh, George S. Kan & Charles O. Forge
The Hewlett- Packard Co.

"Operating principles of a milliammeter that can measure direct currents without opening the circuit or loading.
"Direct current can be measured easily with a clip-on current probe. The probe simply clips around the conductor without requiring that the circuit be opened or disturbed in any way."

me> Will it measure DC? I don't think mine does.

My new one does. Probably Hall, not flux-gate.

{EDIT: Split this topic from http://el34world.com/Forum/index.php?topic=8533.msg184156#msg184156 - HBP}

[eleventeen]

Excellent find, those archived Radio-Electronics mags!!


Those were my nirvana as a kid, I loved those, I read them 50 times. I have several from the mid-fifties.


I have to get with HBP, I have some hp meter parts I offered him (mainly the chopper ass'y) and we need to finish that deal.

[HotBluePlates]

Yes, awesome find!

And yes, we'll have to finish up doing what we talked about quite a while back.  I fixed a "non-functioning, as-is" HP 412A not too long ago. Fortunately, the chopper assembly was working fine; a couple of the #12 lamps in the assembly weren't lighting. 1 or 2 had burned open filaments, and all of them needed a dose of DeOxit on the lamp socket contacts. Afterwards, it worked flawlessly with no other repair needed.

[HotBluePlates]

It appears the same trio (possibly among the engineers who conceived and designed the clip-on d.c. probe) wrote up the 428A for HP Journal June 1958. The Electronics World article appears to be an updated version, clarifying the theory of operation and adding in features of the soon-to-be-released 428B, which two of the authors covered in the HP Journal Nov. 1961.

Tell 'em how it works & why it's so cool, to drum up business. I guess "information/articles as advertising" isn't new; plenty of audio- and guitar-related magazines could be accused of having articles that are little more than extended ads for a product. Doesn't matter as long as the article & product are as cool as this clip-on current probe and its articles.

[PRR]

> I guess "information/articles as advertising" isn't new;

Gernsback invented radio-rags to sell his over-stock of radio parts. Part of that was telling newbs what the parts were for. He also took ads from other radio-related companies. And he ran nice reviews of other products: Radio News Dec 1928 has a fawning article about a Silver-Marshall screen-grid radio on page 538 (Silver-Marshall ad on page 518).

I'm sure he didn't invent product articles related to potential advertising. This was well established in car and home-improvement magazines in the 1950s, surely reflecting long practice.

Nice reviews really do encourage more advertising and more magazine income.

Something truly new and exciting is very-very rare; publishing such puff to a wide audience really is the highest calling of editors and engineers, quite aside from the money.

Radio-News also promoted Hugo's pioneering science-fiction rag, Amazing Stories:
"In Our December Issue:
"The World at Bay, by B. and Geo. C. Wallis. The chapters of the final instalment of this story are vibrant with excitement and strategy to combat the horrors of the Troglodytes and their unknown deadly poisonous gas. It is no mean job to fight the fiends in their strangely devised helicopters, run by radium energy. But not once is the human interest part of the story allowed to lag.
"The Space Bender, by Edward L. Rernenter. May it not have been, after all, purely accidental that the anthropoid adapted itself to varying conditions on this planet more quickly than the others, and so finally evolved into the higher animal -a human being? It is an interesting conjecture, what the results of a snake or fish ancestry, for instance, would be like.
"Before the Ice Age, by Alfred Fritchey. We know practically nothing about the "pre- record" civilizations, but this story told with the easy facility of sailor-inn charm and freshness, makes delightful reading, though there is plenty of food for thought.
"The Appendix and the Spectacles, by Miles J. Breuer, M.D. We are sure that all those readers who have read Dr. Breuer's short stories of medical science and psychology, will be glad to welcome him back. In this new story, our author enters into a slightly new combination with his medical science."

[jjasilli]

These archive sites -- Am Radio Museum & HP -- are a great find.  Thanks for these postings!