Convection current in electricity

In summary, this conversation covers what convection current is, how it is different from other current types, and an example of a convection current.
  • #1
StefanDoby
3
0
So, I randomly came upon this in a textbook that I was skimming and I think I have a very very surface ideea of what it's about but I want to read and know more in order to understand the fenomenon in much more detail. Any help in any form would be much appreciated!

P.S.: This is my first post here, so yay!
 
Physics news on Phys.org
  • #2
Interesting. This is the first time I've ever heard the term 'convection current' in the context of electricity and electrical charges. My very, very brief reading into the subject tells me that convection current is the movement of electrical charges in the absence of an electric field. One example is the movement of electrical charges in clouds due to air currents.
See here: https://forum.allaboutcircuits.com/threads/electrostatics-current-convection-conduction-part-1.3227/

Also found: "convection current density is associated with beams of charged particles or motion of charged insulator,
image014.png
is the volume charge density and
image016.png
is its velocity"
From here: https://regi.tankonyvtar.hu/hu/tartalom/tamop425/0033_SCORM_GEFIT6102-EN/sco_02_01.scorm

And: "Convection current consists of charged particles moving in response to mechanical forces, as opposed to being guided by the electric field (Sections 2.2 and/or 5.1). An example of a convection current is a cloud bearing free electrons that moves through the atmosphere driven by wind."
Here: https://www.circuitbread.com/textbo...nductivity/convection-and-conduction-currents
 
  • Like
Likes davenn and Baluncore
  • #3
StefanDoby said:
So, I randomly came upon this in a textbook that I was skimming and I think I have a very very surface ideea of what it's about but I want to read and know more in order to understand the fenomenon in much more detail.
Welcome to PF.
Perhaps you could identify the textbook and the subject being covered.
 
  • #4
Where I first encountered this topic was in an old romanian textbook that I have called "Physics". The topic is part of a chapter called "Types of electric currents"
Here is section where they briefly touch on convection current
20210420_093450.jpg

20210420_094651.jpg
 
  • #5
This section appears to be discussing the flow of space charge under the influence of an electric or magnetic field. It differentiates it from conduction in a metalic conductor. In English we do not use the term "convection current" in the same way.
TIPURI DE CURENTI ELECTRICI
TYPES OF ELECTRIC CURRENTS

In clasificarea curentilor electrici dupa originea lor fizica, este necesarsa se tina seama de faptul ca un current electric este, totdeauna, un flux de sarcinii electrice.
In classifying electric currents according to their physical origin, it is necessary to take into account the fact that an electric current is always a flow of electric charge.

Deoarece acest flux de sarcini poate sa posede caracteristici diferite, curentii electrici se clasifica in; current electric de convectie, current electric de conductie si current electric de polarizare.
Because this flow of charges may have different characteristics, electric currents fall into; electric convection current, electric conduction current and polarization electric current.

Curentul de convectie este dat de miscarea particulelor incarcate produse de surse externe. Cind o unda electromagnetica (un cimp electromagnetic, variabil in timp, care "calatoreste", sau se propaga, purtind cu el o energie finita) trece printr-un mediu, asupra sarcinilor electrice se exercita o forta, ecuatia dinamica de echilibru aplicindu-se atit ionii pozitivi, cit si la electronii de sarcina negativa:
The convection current is given by the movement of charged particles produced by external sources. When an electromagnetic wave (an electromagnetic field, variable in time, which "travels", or propagates, carrying with it a finite energy) passes through an environment, a force is exerted on electric charges, the dynamic equation of equilibrium being applied both positive ions and negative charge electrons.

p( E + v X B ) = d/dt ( m v ). ( VIII. 183 )

Astfel, notind cu p+ si p- densitatile sarcinilor pozitive si, respectiv negative, prezente in mediu si cu v+ si v- vitezele respective ale acestor sarcini, densitatea de current electric de convectie, intr-un punct al mediului, este;
Thus, noting with p+ and p- the densities of the positive and, respectively, negative charges present in the environment and with v+ and v- the respective velocities of these charges, the density of convection electric current, in a point of the environment, is;

Jcv = p+v+ + p-v- ( VIII. 184 )

Ecuatia (VIII. 184) experima ca densitatea curentului electric de convectie sete specificata de o densitate de sarcina electrica si de o viteza coresponzind la un punct.
Equation (VIII. 184) states that the density of the electric convection current is specified by an electric charge density and a velocity corresponding to a point.

Ca exemplu de current electric de convectie este curentul electric care “trece” intre anod si catod intr-un tub cu vid.
An example of a convection electric current is the electric current that "passes" between the anode and the cathode in a vacuum tube.

Cea mai importanta caracteristica a fluxului curentului de convectie intr-un tub cu vid este ca regiunea dintre catod si placa este in realitate incarcata; adica, o sarcina negativa neta nete prezenta totdeauna cind catodul este incalzit.
The most important feature of the convection current flow in a vacuum tube is that the region between the cathode and the plate is actually charged; that is, a net negative charge is always present when the cathode is heated.
 
  • #6
Baluncore said:
This section appears to be discussing the flow of space charge under the influence of an electric or magnetic field. It differentiates it from conduction in a metalic conductor. In English we do not use the term "convection current" in the same way.
Thanks for the answer, I'll follow the rabbit hole a little bit more.

What did you use to translate the stuff that were in the picture that I sent?
 
  • #7

1. What is a convection current in electricity?

A convection current in electricity is a flow of electrically charged particles, such as electrons, through a conducting medium, caused by a difference in temperature or density within the medium.

2. How does a convection current form?

A convection current forms when there is a temperature difference within a conducting medium. The hotter particles rise, while the cooler particles sink, creating a circular flow of charged particles.

3. What is the role of convection currents in electricity?

Convection currents play a crucial role in the distribution of heat and electricity. In the Earth's atmosphere, convection currents drive weather patterns. In electrical circuits, they help to distribute heat and maintain a steady flow of electricity.

4. How does convection current affect the efficiency of electrical devices?

In electrical devices, convection currents can impact efficiency by causing heat buildup and potentially damaging components. However, they can also be harnessed to improve efficiency, such as in the case of convection ovens.

5. Can convection currents be controlled or manipulated?

Yes, convection currents can be controlled and manipulated through various means, such as using insulation to prevent heat loss and directing airflow in a specific direction. In some cases, convection currents can also be harnessed for specific purposes, such as in the case of geothermal energy production.

Similar threads

  • Electromagnetism
Replies
4
Views
811
  • Electromagnetism
Replies
3
Views
739
Replies
17
Views
1K
Replies
1
Views
835
Replies
2
Views
642
Replies
3
Views
772
  • Classical Physics
Replies
9
Views
230
Replies
20
Views
911
Replies
9
Views
600
  • Science and Math Textbooks
Replies
19
Views
676
Back
Top