26 Jan
2004
26 Jan
'04
3:50 p.m.
----- Original Message -----
From: "Bryan Blackburn" <oldcomp(a)cox.net>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Sent: Monday, January 26, 2004 3:22 PM
Subject: Re: Batteries, wallwarts, voltages and currents Re: New Classic
Finds and etc. (Long)
> reason that your phone smoked was the it's design relied on the internal
> impedence (a fancy word for resistance(R) ) to limit the current. When
you
Close, but although both are measuered in Ohms, impedence includes
another factor: Phase. Resistance is non reactive. That is, it does not
change with the frequency of the source voltage. Impedence is a
combination of resistance and reactance (capacitive and/or inductive),
and along with phase, can change with the frequency of the applied
voltage.
-Bryan
Even resistive loads change a little from the second you apply power until
the circuit has heated up to operating temperature. The metal wire used in a
toaster has a different resistance cold then it does glowing cherry red
burning your toast so amperage will vary a bit (maybe up to 15% depending on
the metal wire used or more if silicon carbide is used).