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From: john larkin <jlarkin_highland_tech>
Newsgroups: sci.electronics.design
Subject: Re: Omega
Date: Sun, 30 Jun 2024 07:38:19 -0700
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On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
wrote:

>On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
><jlarkin_highland_tech> wrote:
>
>>On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com>
>>wrote:
>>
>>>Gentlemen,
>>>
>>>For more decades than I care to remember, I've been using formulae
>>>such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
>>>even giving a thought as to how omega gets involved in so many aspects
>>>of RF.  BTW, that's a lower-case, small omega meaning
>>>2*pi*the-frequency-of-interest rather than the large Omega which is
>>>already reserved for Ohms. How does it keep cropping up? What's so
>>>special about the constant 6.283 and from what is it derived?
>>>Just curious...
>>
>>2 * pi.
>>
>>If a thing 1 unit in radius rotates one time per second, its
>>circumference is 2pi so its rim velocity is 2pi/second.
>>
>>A capacitor current depends on the rate of change of the voltage. 
>>
>>  I = CV/T
>>
>>A 1 volt peak 1 Hz  sine wave has its max rate of change at the zero
>>crossing, and that rate is 2pi volts/second. So 1 farad driven with a
>>1 Hz 1 volt peak sine wave has a peak current of 2pi amps.
>>
>>You can Spice all that to get a feel for things.
>
>Thanks, John. This is the fundamental stuff I just overlook since the
>need for it so rarely crops up. It's easier to take an abstraction
>level higher and lose all the vital detail in the process.

It's good to understand the basics, but I mostly use Spice these days,
even for simple things like voltage dividers.

>You're up early today. Off to church are we?

No, I just woke up early with a zillion ideas. That happens some
times.

Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
good day to stay close to home. Traffic and parking and everything
will be a nightmare.

https://sfpride.org/parade

https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/Pink_Triangle.jpg?rlkey=n4xinzzm39bms9w04syb7egkx&raw=1