Comment "On rectifiers and diodes"

Discussion in 'General Electronics Chat' started by C H Cooke, Sep 15, 2011.

  1. C H Cooke

    Thread Starter New Member

    Sep 15, 2011
    A diode may be thought of as like a switch: “closed” when forward-biased and “open” when reverse-biased.

    I disagree with with this statement-when forward biased, electrons flow
    through the diode-granted opposite to the conventional current flow
    direction. When reverse biased this current is not allowed

    So why say the switch is closed when forward biased? Your picture shows the light coming on
    when forward biased,and staying off when when reverse biased. So it would again appear that
    forward biased is the "open" switch.
    Last edited: Sep 15, 2011
  2. MrChips


    Oct 2, 2009
    What you say makes no sense. Can you elaborate on why you think that forward bias is the "open" switch?
  3. Adjuster

    Well-Known Member

    Dec 26, 2010
    This is simply a problem of definition: a long-established convention that the original poster may not be aware of.

    In normal usage in technical English, an open switch passes no current (think open-circuit). A closed switch can pass current.

    Thinking of an old-fashioned knife switch may help to reinforce the idea. The switch is off when the gap is open, on when the gap is closed.
    Last edited: Sep 15, 2011
  4. MrChips


    Oct 2, 2009
    Ah, I get it! The OP is thinking that "open" means the gate is open and it lets the sheep out:)
  5. colinb

    Active Member

    Jun 15, 2011
    open vs. closed - if you end up combining electrical relay controls with fluid control systems, it gets really ugly. It's frustrating that for electrical circuits, “closed” means current can flow but for fluid valves, “closed” means there is no flow.
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
    Especially when they use water pipes as an analogy of electric flow.:)