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Re: Cal Lab Magazine - International Journal of Metrology

 

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I was also corrected once on the time base side of things:

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ns = nano second

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nS = nano siemens

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apparently, some areas this is the unit of interest and is taken quite seriously.

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Eric

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From: [email protected] <[email protected]> On Behalf Of Dr. David Kirkby, Kirkby Microwave Ltd
Sent: Wednesday, August 31, 2022 9:26 AM
To: [email protected]
Subject: Re: [Test Equipment Design & Construction] Cal Lab Magazine - International Journal of Metrology

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On Wed, 31 Aug 2022 at 01:43, Tom Lee <tomlee@...> wrote:

The rule is that units named for people are not capitalized when spelled out. That assures that "two watts" is a measure of power, while "two Watts" refers refers to two family members.

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I said earlier that I thought the s should not be there, and cited an BIPM brochure, which did not actually substantiate my statement.? However, this document from the BIPM does.

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"A concise summary of the International System of Units, SI"

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It gives a logical reason why "2 watt" is correct, and "2 watts" is not.

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To quote

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"Unit symbols are written using roman (upright) type, regardless of the type used in the surrounding text. They are mathematical entities and not abbreviations; unit symbols are never followed by a full stop (except at the end of a sentence) nor by an ¡®s¡¯ for the plural. The use of the correct form for unit symbols is mandatory, and is illustrated by examples in the SI Brochure"

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Unfortunately, that SI Brochure is not totally consistent, with both "683 lumen per watt" and "683 lumens per watt" in the same document. Also, multiple references to newtons, but I think the newton is the only unit to suffer from this "error". You will not find any references to farads, amperes,


If the IEEE wants "2 watts", and not "2 watt", then it's their publication, so they can have it. But I don't think it is technically correct. But I am not impressed with the way the IEEE accepts both positive and negative numbers in dB for the return loss of passive components. In one issue of a journal you will see someone write that an antenna had a return loss of -15 dB, and in another article the return loss is quoted as 15 dB. Fortunately the context is usually obvious.

Dave

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