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Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024
    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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Vintage Littelfuse Advertisement
October 1953 Radio-Electronics

October 1953 Radio-Electronics

October 1953 Radio-Electronics Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

Optical illusions have always been a big attention-getter. Many companies have employed their intrigue to promote their products and/or services. This optical illusion was used by Littelfuse (not Littlefuse*), a company founded in 1927 and still in business today, to draw attention to a full-page advertisement in a 1953 issue of Radio-Electronics magazine. More interesting than the illusions, though is the information presented is about how their proprietary glass-encased fuse design will always burn out in the center of the link, where it is visibly obvious. It might seem trivial, but having tested fuses that appeared to be good but tested bad, that is a great feature. Modern plastic-encased fuses with spade terminals like those found in automobiles have a similar feature that makes visual inspection very easy and unmistakable. In another Littelfuse ad, they educate the reader about how a fuse's amperage rating is not the amperage level at which it will blow, but the continuous current it can carry without blowing. A lot of people are now aware of that distinction.

*Interesting sidenote from "Our History" page on the Littelfuse website:

"Why do we spell it that way? When the U.S. government refused Edward V. Sundt a patent for Little fuse on the grounds that the words were too common, our founder compromised by reversing the l and the e to form Littelfuse."

Littel is a surname of English and Netherland origin, but it is also considered a variation of "little," so that helps justify its use in Littelfuse. Urban Dictionary says "littel" in modern lingo means, "A person or animal of a remarkable and distinct cuteness, regardless of size," it is doubtful that is the origin.


Vintage Littelfuse Advertisement, October 1953 Radio-Electronics - RF Cafethings are NOT as they seem

Things are not as they seem ...

These two fuses look alike ...

But they are not.

This is a perfect square within the circle - it is an optical illusion that the sides bend.

This fuse may burn out anywhere along the length of the filament even in the cap - this blown fuse is impossible to detect visually.

This Littelfuse has a controlled blowing point - the filament is plated throughout its length except in the very center - the fuse will always blow here. A blown Littelfuse can be detected immediately - a Littelfuse feature.

Littelfuse holds more design patents on fuses than all other manufacturers combined.


Des Plaines, Illinois



Posted November 18, 2020

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