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You can't just plug your computer into the wall

IP.com Disclosure Number: IPCOM000131398D
Original Publication Date: 1979-May-01
Included in the Prior Art Database: 2005-Nov-10
Document File: 5 page(s) / 23K

Publishing Venue

Software Patent Institute

Related People

James V. Dinkey: AUTHOR [+3]

Abstract

The Open Channel is exactly what the name implies a forum for the free exchange of technical ideas. Try to hold your contributions to one page maximum in the final magazine format (about 1000 words). We'll accept anything (short of libel or obscenity) so long as it's submitted by a member of the Computer Society. If it's really bizarre we may require you to get another member to cosponsor your item. Send everything to Jim Haynes, Applied Sciences, UC Santa Cruz, CA 95064.

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This is the abbreviated version, containing approximately 23% of the total text.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

This record contains textual material that is copyright ©; 1979 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Contact the IEEE Computer Society http://www.computer.org/ (714-821-8380) for copies of the complete work that was the source of this textual material and for all use beyond that as a record from the SPI Database.

You can't just plug your computer into the wall!

James V. Dinkey

The Open Channel

The Open Channel is exactly what the name implies a forum for the free exchange of technical ideas. Try to hold your contributions to one page maximum in the final magazine format (about 1000 words).

We'll accept anything (short of libel or obscenity) so long as it's submitted by a member of the Computer Society. If it's really bizarre we may require you to get another member to cosponsor your item.

Send everything to Jim Haynes, Applied Sciences, UC Santa Cruz, CA 95064.

If you think a dedicated line is the end of your computer problems. read this

In much of their sales literature. the various computer manufacturers state that all you have to do to get their computers operating is to merely plug them into the wall

Not true!

What the manufacturers really mean is that if the power available at the wall is manufacturered by Snow White and the Seven Dwarfs, you stand a pretty good chance of not having power supply prob lems.

But in reality. with the advent of distributed data processing. and more recently with the advent of the personal home or office system. the computer has been attached to whatever is handy. rather than to a properly selected power source We're all guilty of the choice; we just don't want to pay the money for a proper power supply So we hope all will go well and despair when it does not.

In reality. the dedicated line is not nearly sufficient protection.

Most manufacturers state in the material delivered with the computer that the voltage is to be 117 V + 15% or 2()% On the surface of it that looks fine. except that there are factors that virtually all personnel tend to conveniently forget -like spikes. Inductive com portents generate spikes Copiers and plant air conditioning units are the most common spike generators. Even high current loads. such as heaters. generate spikes in association with the inductance of the distribution wiring and service tran sformer.

For the moment. let's look at the specification of the computer. That statementof 117 volts + 2()% means 117 volts + 23 4 volts (or not less than 93.6 volts or more than 14() 4 volts. all RMS).

But it is a demonstrable fact that an office copier will often generate spikes in excess of 1()() volts when turned off for the day and spikes of about 110 volts while running. These voltages

IEEE Computer Society, May 01, 1979 Page 1 IEEE Computer Volume 12 Number 5, Page 81

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You can't just plug your computer into the wall

ride the normal sine wave voltage...