On 09/05/2016 01:57 PM, scott wrote:
>> I guess it depends on what your goal is. If your goal is "design
>> circuitry that can be manufactured in the real world and sold to people
>> at a profit", there's an awful lot of real-world stuff that's quite
>> important. If your goal is "I wonder how my PC works", then... not so
>> much.
>
> Unless, by "how my PC works", you mean why it needs a million tiny (or
> not so tiny) capacitors on the motherboard,

I have to admit, I have frequently wondered why this *digital* device 
has hundreds of *analog* components on it (mostly capacitors and 
inductors). I mean, I get why they're on the motherboard rather than on 
the silicon die, but why do you need them at all?

> or why the tracks are laid
> out that way, or why certain parts are grounded together and certain
> parts are not, or why there are transformers next to the ethernet
> socket, why there is a heatsink on some ICs but not others ... etc.

Is there a simple relationship between circuit design and heat output? I 
mean, is it something as simple as number of switching elements and how 
fast they switch per second? Or is it something more complicated?

>> Tangentially:
>>
>> https://hackaday.com/2016/04/30/megaprocessor-is-a-macro-microprocessor/
>>
>> Apparently the LEDs consume most of the power. And where I was thinking
>> that LEDs are extremely low-power...
>
> You mean like this one? :-)
>
>
http://www.leds4less.co.uk/100w-led-floodlight--ip65-waterproof--1000-watt-equivalent-459-p.asp
>
> Are you aware that you can light your home/office with LEDs now, or
> light your way when cycling with them, or even some newer cars use them
> for headlights too?

Well yes, but those aren't what the guy was using. He's not trying to 
light the building, just tell you which circuits are on or off. :-P

> Needless to say, LEDs come in all sizes, but a rough rule of thumb is
> that they convert about 10% of the electrical power used into visible
> light (the other 90% going to heat). Which makes them "low power",
> compared to an equivalent "old" style bulb with the same light output.

Interesting. I didn't realise the efficiency was still that low. 
(Obviously incandescent bulbs are notoriously inefficient. But I thought 
LEDs were a bigger step forward than that...)

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