Anode or Cathode?

Discussion in 'General Electronics Chat' started by #12, Jul 7, 2011.

  1. #12

    Thread Starter Expert

    Nov 30, 2010
    Growing up with vacuum tubes, I can't be fooled about their anodes and cathodes, but rectifier diodes, LEDs, 7 segment displays, SCR's, Triacs, zeners, are not in my mental inventory. I don't get it, how these things are labeled, and I always have to look it up. What I really need is a statement about electron flow and which one is the anode, or something like that, so I can remember which end is which.

    Like, with a vacuum tube, external electrons enter the cathode and leave through the anode. Is this valid for semiconductor diodes and LEDs, etc?

    It's just a memory problem.
    Last edited: Jul 7, 2011
  2. SgtWookie


    Jul 17, 2007
    Well, I think of it as the electron flow goes opposite the way the "arrow" is pointing; just like the arrow on the emitter in transistors, etc.

    And yes, tube/valve cathodes are the emitters of electrons, and they are collected on the plate.
    #12 likes this.
  3. Ron H

    AAC Fanatic!

    Apr 14, 2005
    In a word, yes.
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  4. #12

    Thread Starter Expert

    Nov 30, 2010
    Thanks. I'm gonna pretend that I understand, post answers, and see if I get corrected.

    If you look carefully, you'll see that I have never called anything an anode or a cathode in my posts. That's because I wasn't sure. Now I have a new tool.