Jim W8ZR Garland wrote in part:
Concur with Bill W6WRT re "positive vs negative" convention in describing
current. The
convention we use now is left over from at least a hundred years ago when
a scientist
guessed wrong about the polarity of the electron. To me, thinking in
terms of the direction
of electron movement is far more clear.
-Gene WB8WKU
Sorry to disagree with you and Bill, Gene, but the standard convention for
electric current makes a lot of sense, and it's not just that somebody
guessed wrong a century ago about the polarity of electrons. The important
concept is that electric current is a statistical concept. Electric current
is sometimes carried by positive charges, sometimes by negative charges, but
the sign of the charge carrier is an entirely separate issue from the
direction of current flow. In a vacuum tube, plate current flows into the
plate and out of the cathode, even though the motion of the electrons in the
tube envelope is in the reverse direction. Similarly, current flows into
the collector of an NPN transistor and out the emitter (hence the words
collector and emitter), even though transistor current may be carried by
holes. Similarly, current flows out the positive terminal of a battery and
returns into the negative terminal, no matter whether the charge of the ions
in the battery are positively or negative. It would be a nightmare to keep
track of current flow, if the direction of flow depended on the sign of the
underlying charge carriers. You might have situations where current flows
out of a B+ supply to the plate of a tube, and then is annihilated by
current flowing in the opposite direction from within the tube, coming from
the cathode.
Bull! Conventional current flow was a wrong guess.
I'm sorry I must say ...
Please explain to us how the CURRENT flows up the ultor lead to the
side of the bell of the cathode ray tube, runs in and around the
aquadag inside the bell and at the right place jumps off and strikes
that precise spot on the screen (that is based on the magnet field that
the current is yet to pass though) then is shoots through that varying
magnet field (when it is at the exactly correct magnitude) at high
velocity at a tiny hole in the end of the electron gun, (which under no
circumstance fails to go through) and lands ONLY on the only hot thing
at the bottom of the gun.
Yea sure!
The flow of holes through conducting materials is the RESULT of the
motion of ELECTRONS. To say other wise makes me say BULL.
Only some (older) larger universities and a few manufacturing
companies (GE and a few others) hang on to the obsolete conventional
current flow that should be forgotten by everyone. Why? Because
electrons are what IS MOVING. The flow of electron is electricity.
(and lighting)
--
Ron KA4INM - Youvan's corollary:
Every action results in unwanted side effects.
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|