Electrical flow

[WILD1]

That's what I can't actually get straight in my head. In a tube electrons are actually boiled off the cathode [neg charge] and absorbed by the anode [positively charged]. So they are flowing from negative to positive [electron flow]. So how can engineers use conventional flow diagrams.

[dgta]

Originally Posted by WILD1

So how can engineers use conventional flow diagrams.

We turn the schematics upside-down and it becomes very intuitive

[hpasternack]

Originally Posted by WILD1

That's what I can't actually get straight in my head. In a tube electrons are actually boiled off the cathode [neg charge] and absorbed by the anode [positively charged]. So they are flowing from negative to positive [electron flow]. So how can engineers use conventional flow diagrams.

Because we are very, very clever.

[GloBug]

The flow of electrons does come from the ground. You are correct.

Because humans are usually at ground potential, you want to segregate and control positive reception for safety. (Isolation) Current needs to be controlled for safety.

The Anode is not always positive. A device consuming power the anode is positive. A device giving power has a negative anode.

They are more concerned with current flow, rather then electron flow. If you use the old water analogy, it's easier to grasp what they are doing. (Ignore the fact that the electrons are flowing the opposite way.)

[WILD1]

And I thought that no one on this site had a sense of humor. What I am working on is a B+ power supply. In the schematic they show a positive voltage coming into a regulator tube at the anode or plate and leaving regulated to a different voltage through the cathode. Isn't this contrary to the way a tube works?

Dazed and confused,
WILD!

[GloBug]

Yes and No.

The schematic shows current flow.

Electrons are negatively charged, hence the attraction to the positive terminal, flowing from the ground.
The "Positive" terminal is actually a "terminal lacking negatively charged electrons"

I just picture it as water flowing from the positive to save confusion.

[Wavebourn]

Current does not flow. It happens. What flows, is an electro-magnetic wave. It has beginning, but has no end. The beginning of the wave is called Front, an archaic English word for front is Bourn, according to the dictionary, "the line or plane indicating the limit or extent of something"
So, the edge of electro-magnetic flow is Wavebourn. Before Wavebourn it was Nothing.

[M Gregg]

Fun Link:

Conventional Current vs. Electron Flow#

You know if you get to hung up on this your going to get nowhere..

You have to think conventional or your going to get in a real mess.

Yes you can chew this over as much as you like but the bottom line is you need to be able to read the drawing. You will not do this with the way you are thinking. Circuit discussion and physics are OK in the correct place.

If I was to do what you are doing during a fault location I would be their all day and get nowhere. Also other engineers would have no idea what I was trying to do.

And before you ask switch contacts are normaly shown in the non operated state..IE relays are not energised.


Regards
M. Gregg

[DF96]

When trying to understand a device, whether active or passive, it can help to think about conventional or electron flow (whichever is most appropriate for that device).

When trying to understand a circuit it is best to think in terms of signal sources and sinks, for both AC and DC signals (including PSUs). If you try to analyse a circuit in terms of either electron or conventional current you will be confused if you later see the same circuit 'upside down' - literally in the case of transistors, which have two polarities available.

[Miles Prower]

Originally Posted by WILD1

That's what I can't actually get straight in my head. In a tube electrons are actually boiled off the cathode [neg charge] and absorbed by the anode [positively charged]. So they are flowing from negative to positive [electron flow].

All quite true.

So how can engineers use conventional flow diagrams.

Because it doesn't really matter. A Coulomb's worth of electrons (negative charge) moving in one direction is equivalent to a Coulomb's worth of positive charge moving in the opposite direction. The only time it's actually worth it to make a distinction is when considering the physics of solid state devices, or Hall Effect, and unless you're involved in actually designing such devices, it's seldom relevant.

With VTs, you have just the one device: N-Channel, always. When designing for solid state, all that's required is to know the arrows point from P-type layers to N-type layers, and that positive (or less negative) polarities connected to P-layers means forward bias, and the same polarity of connections to N-layers means reverse bias.