Re: [Phys-L] LC circuit simulation

[John Denker <jsd@av8n.com>]

On 08/06/2014 10:05 AM, Bob Sciamanda wrote:
> This effect has real engineering consequences in the required minimization of radiation from power supply circuitry:

We agree there *are* real-world consequences.  We just
don't agree on what the consequences are.

In the following, the operative word is "seems":

> From Am. J. Phys., Vol. 72, No. 5, May 2004 ==>
>
> "For a switched-mode power supply, energy transfers between capacitors
> and inductors are an integral part of its operation. To comply with EMC
> regulations, it seems that the power supply engineer must compromise
> between power lost through adding an external resistor R vs radiation. In
> cases, where this loss is unacceptable, shielding remains the only option."

That is how it might "seem" to someone who is woefully
ignorant of the physics and 40+ years behind the 
state-of-the-art engineering.

In fact, though, the same physics that allows us to
understand capacitors, resistors, and radiation also
allows us to understand /inductors/.  If you stick an
inductor in there, the alleged "lost" or "missing"
energy that those guys are fixated on isn't lost or
missing or dissipated at all.

Proof by construction, as previously described.  What
part of that proof do you not understand?  What part
of that proof would you have trouble explaining to a
high-school student?  (Assuming you drew the circuit
diagram and a couple of graphs, and took your time....)

As for low-ripple low-radiation power supplies, R.D. 
Middlebrook has been all over this for 40 years that 
I know of.  See e.g.
  http://powerelectronics.com/power-electronics-systems/remembering-dr-middlebrook-part-1
and references therein, including
  Remembering Dr. Middlebrook: Part 2
  Remembering Dr. Middlebrook: Part 3
  Power Conversion Synthesis Part 1: Buck Converter Design
  Power Conversion Synthesis Part 2: Zero Ripple Converters
  Power Converter Synthesis Part 3: Near Zero Emissions
  Power Converter Synthesis Part 4: Near Zero Emissions