[rescue] Workers of the World, Unite!

[Joshua D Boyd]

On Mon, Jul 22, 2002 at 10:18:51AM -0700, James Lockwood wrote:

> > Hmm, I'll have to double check what I did to my sister's stereo then.
> > I have a bad feeling I might have put 4 ohm speakers on a 6 ohm amp.
> 
> Mismatching impedances is bad.  It is better to mismatch them (in this
> case) in the direction that approximates an open circuit, though.  With a
> higher impedance load the output stage of the amplifier will be
> undersaturated, but it's better than oversaturation (which is more
> nonlinear can lead to a failure in some designs).

OK.  My formal learning never dealt with design issues, like stressing
components, or if imperfections exist where to put them.  It was
strictly theoretical about how the electrons flowed.
 
> > V=iR?  There isn't exactly any heat in that.  There is W=VA, which
> > relates to heat...  Is that also part of ohm's law?
> 
> E=IR[1].  From this and P=EI we get P=E^2/R.

> 1. Are people really learning "V", "W" and "A" now?

In Physics 2, we did use V for V=iR.  We typically did not use A
though, at least not in that circumstance.  I always remeber W=VA.  I
don't remeber ever seeing W=Vi, so I think they might have used A in
that circumstance, but I could be wrong.  I don't remeber ever seeing
P.

As to V versus E, the explaination was that E was supposed to be
energy generically, while V was energy specifically jeules (spell
checker is making any suggestions, and I want to leave for lunch, so
I'm leaving that mispelled) per coulomb, rather than a generic measure
of energy.  I always think in terms of V, i, w, and R now, except for the
specific equation W=VA.  I probably should try to convert that
equation in my mind to use the same for as the others.

-- 
Joshua D. Boyd