Encountered Confusion upon Learning the Electron Flow of the "Lamp Dimmer Circuit" in the E-Book

Joined Nov 29, 2015
3
So I'm really new at electronics, and I'm trying to learn from the very basic...
As I went to Vol.3, Chapter 3 (http://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/rectifier-circuits/), and looked at this picture:

I "read" this as the electron "started" flowing from the source to the lamp first then to the diode. As opposed to the diode first (related to my understanding of the electron flow convention, no way for the electron to flow to the diode first as the diode will block). Wouldn't anything different (i.e. light being dimmed) happened then? Since the electricity had already go to the lamp first?

dl324

Joined Mar 30, 2015
12,225
The tutorials use electron current, not conventional current.

With the switch in the dim position, the diode only conducts on the positive half of the sine wave.

The order of the diode, switch, and lamp aren't critical as no current flows unless the "loop" is closed.

Joined Nov 29, 2015
3
The tutorials use electron current, not conventional current.
Yes, I'm aware of that, and so the electron should flow like this? Am I correct?

This is why I was confused on the light dimmer picture in the first place, as (in my understanding) the electron flow path would be:
Am I correct in this?

dl324

Joined Mar 30, 2015
12,225
Yes.

MikeML

Joined Oct 2, 2009
5,444
...I "read" this as the electron "started" flowing from the source to the lamp first then to the diode. As opposed to the diode first (related to my understanding of the electron flow convention, no way for the electron to flow to the diode first as the diode will block). Wouldn't anything different (i.e. light being dimmed) happened then? Since the electricity had already go to the lamp first...!
There is no "first" or "second" in a series circuit at any useful time scale. In a series circuit, the current appears everywhere at the same instant!

After there is current, you can worry about its direction...

Joined Nov 29, 2015
3
With the switch in the dim position, the diode only conducts on the positive half of the sine wave.

The order of the diode, switch, and lamp aren't critical as no current flows unless the "loop" is closed.
Hmm, ok, so the order doesn't matter for the "open loop circuit", so what is the difference of the open and closed loop? Is there a topic on AAC that covers this? (searched about it before and with google too but no luck)

There is no "first" or "second" in a series circuit at any useful time scale. In a series circuit, the current appears everywhere at the same instant!

After there is current, you can worry about its direction...
Oh! Don't know that before, what I just knew was that each will have the same number of current, but I had no idea if the current appears in this or that time. My former thought was that current also flows through the circuit (hence the confusion) which is terribly wrong!

Thank you for clearing that up!

dl324

Joined Mar 30, 2015
12,225
Hmm, ok, so the order doesn't matter for the "open loop circuit", so what is the difference of the open and closed loop? Is there a topic on AAC that covers this? (searched about it before and with google too but no luck)
Closing the loop can also be thought of as completing the circuit. Current can't flow unless there is a path for it to flow.

In the circuit you referenced, there's a loop with the diode and one without; and no (indicated) provision for the light to be off.

BillB3857

Joined Feb 28, 2009
2,541
Even though water and pipes and hoses are frequently used to help explain current flow, it must be assumed that all of the pipes and hoses are filled with liquid before any connection is made. It isn't as if a wire needs to fill up like an empty pipe before current flows.