Drive VS Sink

[gogo2520]

Hello
     I don't read enough or I can't remember what read.

 I want to be able to discuss the differences between sinking current and driving current with friends.
     I guess my thinking is if your sinking current your allowing  electrons to go to a positive rail? right
        So if your driving current your releasing electrons so they can go to the positive rail?
   
   Whats the difference/ My thinking might be wrong that is why I am asking
  I'm not even sure if I am using the terms right, hows that for old timers da.
                                                   Thanks in advance
                                                         gogo

[KevinIV]

Yes. You can tell the difference between a current source and a current sink by the polarity of the voltages, which also indicates the direction of electron flow.

[Hero999]

Conventional current flow is used when sourcing and sinking current is concerned.

If an output is driving a load connected to the negative rail then it is said to be a source.

If an output is driving a load connected to the positive rail then it is said to be a sink.

[gogo2520]

Yes. You can tell the difference between a current source and a current sink by the polarity of the voltages, which also indicates the direction of electron flow.

aaaaaaaaaaaaaaaaaah that don't make scene. Electrons will always travel to the Positive rail, Electrons can only hold a negative charge.

   I think what I am thinking is what to call the current at the input or output location like Hero said.
   So the negative rail would be the source and the positive would be the sink. as far as current goes.
   and, if the output of a I/O pin on say a micro controller is positive the it would sinking current right
                                                 gogo

[Hero999]

Just use conventional current flow (flowing from positive to negative) when figuring out how circuits work.

To be picky current doesn't just flow from negative to positive, it flows in both directions simultaniously: electrons travel from the cathode to anode and holes flow from positive to negative.

Don't worry about it, as I said before just use hole flow: a source provides current and a sink sucks it away.