Valve Symbol

Discussion in 'Electronics Resources' started by MaxHeadRoom, Dec 27, 2014.

  1. MaxHeadRoom

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    I think it is more than a coincidence it is identical to the Hydraulic/pneumatic check valve symbol! ;)
    Max.
     
  2. WBahn

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    But it's not. At least it isn't the symbol I've almost always seen, including when I worked hydraulics and pneumatics on fighter aircraft. The most common check valve symbol I've encountered (which is also the ISO standard symbol) is a V with a circle cradled in it which graphically depicts how simple check valves work.

    http://www.engineersedge.com/hydraulic/symbols/hydraulic_iso_check_pilot_valves_.htm

    I'm not saying that the diode symbol isn't used as a check valve symbol, just that I've never seen it used as such.
     
  3. alfacliff

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    Dec 13, 2013
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    there are many symbols for the "valve" rectifier. depending on whether its a filament type, heated cathode type, cold cathode type and such.
     
  4. Glenn Holland

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    A more logical explanation is the arrow points in one direction only like a DO NOT ENTER sign on a freeway off ramp. :)
     
  5. MaxHeadRoom

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    The arrow points to electron flow direction, the vertical line is the blocked direction.
    Max.
     
  6. strantor

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    NO, it points NOT in the direction of hole flow! :p
     
  7. MaxHeadRoom

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    It late, OK.:oops:
    Max.
     
  8. Glenn Holland

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    The symbols for electrical and electronic devices are simply a matter of convention rather than of a physical origin.

    For example, a BPJ transistor can be visualized as two diode symbols pointing either toward or away from the base connection. However a transistor is represented by just one arrow pointing to or from the base and the vertical line has been eliminated.
     
  9. WBahn

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    Huh?

    diode.png

    What direction is the arrow pointing? Left to right.

    What direction are the electrons flowing? Right to left.
     
  10. WBahn

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    Most symbols have some basis in physical devices. A resistor is reminiscent of a heating element. A capacitor suggests plates separated by a gap. An inductor is indicative of a coil of wire. Most of the vacuum tube symbols were suggestive of the vacuum tube elements they represented. The fact that only one element of the BJT symbol carries the arrow reflects the need to distinguish between collector and emitter in most physical BJT devices. In many MOSFET devices, which graphically depict the capacitive nature of the gate to channel implementation, there is no distinction between source and drain and, hence, there are symbols that are symmetric. You can only tell whether it's NMOS or PMOS by the fourth pin, which shows the parasitic bulk-channel diode.
     
  11. MaxHeadRoom

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    I was about to correct it when Mr Strantor corrected me!
     
    Last edited: Jan 15, 2015
  12. strantor

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    If I actually correctly corrected you, it was by chance; I was attempting to be facetious. Apparently I was accidentally correct?
     
  13. WBahn

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    Amazing how quickly people from all over the world can respond to things. It's great... but it has it's downsides, too. :D
     
  14. WBahn

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    Actually, you weren't -- but I figured you were being facetious and knew that saying that it is NOT in the direction of hole flow is the same as saying that it WAS in the direction of electron flow.
     
  15. strantor

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    you got it, good. thanks for restoring my sanity.
     
  16. MaxHeadRoom

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    I figured the symbol originates from around the time B. Franklin assumed current flowed pos to neg.o_O
    Max.
     
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