BigDaddy Greg and I are going to have to agree to disagree. Where is Randy? I don't think an electron moves from anode to cathode and leaves a positive charge behind. (Although we do say that the "current" is moving from anode to cathode.) Electrons are attracted to the positive. Lightning...strikes the ground, it doesn't shoot from the top of trees into the clouds. Those are electrons moving from - to +
Greg and I are going to have to agree to disagree.
Where is Randy? I don't think an electron moves from anode to cathode and leaves a positive charge behind. (Although we do say that the "current" is moving from anode to cathode.) Electrons are attracted to the positive.
Lightning...strikes the ground, it doesn't shoot from the top of trees into the clouds. Those are electrons moving from - to +
Ah Hem....
Components of the strike move both up and down the main flash can be cloud down or earth up...
Cloud-to-ground (CG) lightning is a lightning discharge between a thundercloud and the ground. It is initiated by a stepped leader moving down from the cloud, which is met by a streamer moving up from the ground.
CG is the least common, but best understood of all types of lightning. It is easier to study scientifically, because it terminates on a physical object, namely the Earth, and lends itself to being measured by instruments on the ground. Of the three primary types of lightning, it poses the greatest threat to life and property since it terminates or "strikes" the Earth. The overall discharge, termed a flash, is composed of a number of processes such as preliminary breakdown, stepped leaders, connecting leaders, return strokes, dart leaders and subsequent return strokes.[37]
Cloud-to-ground (CG) lightning is either positive or negative, as defined by the direction of the conventional electric current from cloud to ground. Most CG lightning is negative, meaning that a negative charge is transferred to ground and electrons travel downward along the lightning channel. The reverse happens in a positive CG flash, where electrons travel upward along the lightning channel and a positive charge is transferred to the ground. Positive lightning is less common than negative lightning, and on average makes up less than 5% of all lightning strikes.[38]
Singing in the Rain (ROAR)
PS: It is a moot point, that much current will kill your LED.
ROQR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
gregc"current" flows from positive to negative. electrons from from negative to positive.
electrons from from negative to positive.
huh? because they figured out electric charge using batteries and galvanometers labeled with + and - terminals before they discovered the sub-atomic structure of atoms and electrons
greg - Philadelphia & Reading / Reading
This trips up people when they are learning theory. Convention has current flowing postive to negative, but physics says it's the electrons moving from negative to positive.
It only really matters when studying how a semiconductor actually works, so the easiest thing to do is use the conventional model which most all circuit theory is based on.
As for Tom's bicolor LEDs - there's one more type, the kind with only 2 leads. It is composed of two different LEDs wired anti-parallel. Used to be most all were red and green, but you can get different color mixes these days. Assumign red/green are the two colors, with a 2 lead bicolor LED, you make one side + and the other - and it lights up red. Flip the + and - and it lights up green. Pass AC through it, and it lights up yellow-ish. Shade depends on the duty cycle of the AC, if it's perfectly symmetrical, like standard sine wave AC, the red and the green are on the same amount of time, and any color variatioon is strictly due to the difference in efficience of red and green LEDs. Make one side stay positive longer than the other, and either the red or the green stays on longer, shifting the color. This can easily be seen in the track status LEDs on Digitrax DCC systems, and then using address 00 for zero stretching. Increase the throttle in forward and one side is positive longer than the other. Reverse and increase the throttle, and now the other side is more positive, and the LED changes color.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
BigDaddyI don't think an electron moves from anode to cathode ...
correct
"current" flows from positive to negative.
current is the flow of the holes left by electrons (not in the same direction as the flow of electrons)
BigDaddyLightning...strikes the ground, it doesn't shoot from the top of trees into the clouds.
lightning goes in both directions and between clouds.
Henry
COB Potomac & Northern
Shenandoah Valley
if this image with the triangular shape similar to the symbol of a diode is used to illustrate the direction of current, the dots represent the positive charge (the hole left by the movement of the electron) moving from right to left, anode to cathode.
EDIT By convention you are correct. Current is defined as moving from positve to negative
However, electrons are what is actually moving and they look like the pacman thingies with a negative charge, so they move from negative to positive.
non copyrighted image.
So do I have this right?
Edit: And if current flows through both anodes simultaneously, you get a yellow aspect.
Thanks,
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.