some elementary questions

[turingcomplete]

Hey everyone,

I am new to the world of electronics and I have some very basic questions. The first question is, I understand that an electric current is due to the movement of charge in a conductor. But the particles that move within the conductor, are they just electrons or they can be atoms that are positively or negatively charged?. Second question, I understand that a voltage source supplies charge with energy to create an electric current in a conductor, but what does a current source do?.. Actually if someone could explain to me what do voltage and current sources do, I would really appreciate it because i am having trouble understanding that. Looking forward to receive your answers.

 

[davenn]

Hey everyone,

I am new to the world of electronics and I have some very basic questions. The first question is, I understand that an electric current is due to the movement of charge in a conductor. But the particles that move within the conductor, are they just electrons or they can be atoms that are positively or negatively charged?.

No its just the electrons that are moving

Dave

 

[turingcomplete]

Thanks for the reply, so current will always consist of negatively charged electrons.. So I suppose the job of the voltage source is to supply them with energy to force them to move in a certain direction since for example they will be naturally repulsed away from the negative terminal of the voltage source. Am I correct?

 

[Laplace]

In the physical world, current will always consist of negatively charged electrons. However, in electronics you will not usually be working with the physical world but rather with abstractions of the physical world where the rules can often be whatever you want them to be. For instance, in circuit analysis it is most often the convention that current flows from plus to minus, whereas electrons flow from minus to plus. Positive current flow turns out to be conceptually simpler to use, and it works well as long as you are consistent.

A voltage source supplies a constant voltage. A current source supplies a constant current. You can think of a current source as a special voltage source that adjusts its voltage in order to keep the current constant, just as you can think of a voltage source as a special current source that adjusts its current in order to keep the voltage constant.

 

[turingcomplete]

Thanks for all your replies.