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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 (if any) 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.

See all available vintage Radio-Electronics articles.

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
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