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Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2016
Webmaster:
Kirt Blattenberger,
 BSEE - KB3UON

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 Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

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Electric Wristwatch
February 1958 Radio Electronics Article

February 1958 Radio-Electronics

February 1958 Radio-Electronics Cover - RF Cafe[Table of Contents]

These articles are scanned and OCRed from old editions of the Radio & Television News magazine. Here is a list of the Radio-Electronics articles I have already posted. All copyrights are hereby acknowledged.

The world's first electric wristwatch went on sale on January 3, 1957 - the Ventura model, by Hamilton Electric, and it retailed for $200. I use the event as the theme of the RF Cafe logo for that day in history. Unlike today's electric watches which use a crystal for timing, the early watches used a pulsed motor to energize the balance wheel coil, in place of a mainspring and an escapement mechanism. The watch shown in World's First Electric Watch Sold.  Please click here to visit RF Cafe.this article from the February 1958 edition of radio-electronics is a model 500, which you can find more detail about on the Unique Watch Guide website.


Electric Wristwatch
Electric Wristwatch, February 1958 Radio Electronics - RF CafeThe electronic technician may soon be seeing a new item on his workbench, the electric wrist watch. He may need a powerful magnifying glass or two and a couple of jewelers' tools, but an electric watch is driven by a tiny electric motor using batteries of a highly specialized type and requires service know-how more closely allied to that of a radio technician than the jeweler.

The Hamilton Watch Co., after 10 years of research and testing, has placed an electric wristwatch on the market. Driven by a miniature reaction motor, it has an accuracy of 99.995% and is powered by a button battery with a life of more than 12 months.

A miniature triangular coil is attached to the balance wheel which is used as the motor's rotor. Platinum-alloy permanent magnets, claimed to have the highest energy content of any magnet in the world today, create the motor's magnetic field.

Coil contact is made through a silver-gold-alloy contact on a nonmagnetic spring fastened to a mounting plate (see figure). As the wheel oscillates its contact brushes against the spring contact, sending a pulse of current through the coil. Timing is based on the natural oscillation period of the balance wheel.




Electric Wristwatch Mechanism - RF Cafe

Electric Wristwatch Mechanism




Posted  January 15, 2014