Connect with us

Electronics Memory Aids

Discussion in 'Electronic Design' started by Al, Jun 9, 2004.

Scroll to continue with content
  1. Al

    Al Guest

    Sorta off topic, but for fun!

    Many moons ago, when I transitioned from tubes to transistors, I had
    trouble remembering which symbol to use for PNP or NPN transistors. I
    then read about a great memory aid as follows:

    Pissin 'N a Platter for PNP....and the arrow points to the base.

    Now we've heard a million ones for the resistor color code, so don't
    bother with those.

    Does anyone have any other mnemonics for say N Channel MosFETs and the
    like?

    Al
     
  2. John Larkin

    John Larkin Guest


    The way most people draw mosfets is a mess. I draw them just like
    transistors, but with a little half-capacitor thingie instead of the
    regular base lead. It's much easier to look at.

    |
    |--
    ----------|| n-ch fet
    |>-
    |




    John
     
  3. Activ8

    Activ8 Guest

    a MOSFET with a base? Did you run out of coffee? I've got some
    strong tea made up. Help yourself.
    Huh? The arrow always points toward the n material like the base in
    a npn or the channel in an n channel MOSFET or JFET.

    There's also no capacitor in the "n-ch FET" (?) above



    |
    |-+
    ->| n-ch JFET
    |-+
    |



    |
    ||-+
    ||<- an n-channel MOSFET
    -||-+
    |
    created by Andy´s ASCII-Circuit v1.22.310103 Beta www.tech-chat.de

    ven programmers know that, see? ;)

    I sometimes modify that to show the substrate/source connection the
    way I'm used to seeing it

    |
    ||--+
    ||<-o an n-channel MOSFET
    -||--|
    |


    Oh... One other convention sometimes adhered too is that the lead
    for the gate comes off the source side of the MOSFET so you don't
    have to label them or show the substrate connection.

    or

    |
    ||--+
    || a goofy looking n-channel MOSFET
    -||<-+
    |



    o o
    0 0
    0 0
     
  4. John Larkin

    John Larkin Guest

    Huh yourself. NPNs are drawn with the arrow pointing *away* from the
    N-doped emitter. My mosfet symbol is similar to an IGBT, which is
    functionally consistant with an NPN transistor, except that the "base"
    is insulated.

    Oh, I draw the main center bar solid, like a transistor... couldn't
    show that here in ascii.

    Capacitor? I referred to "a little half-capacitor thingie", which
    there seems to me to be one.
    OK, but I like to put the gate off-center, a bit closer to the source.


    That's the one I hate: it's too busy, and counter-intuitive to me.

    Why not go whole-hog and include the substrate diode?
    I do that for GaAsfets, off-center but not all the way to the source.
    It's obviously p-channel! That's why I like the "transistor"
    convention.

    Luckily, I don't have to please anybody but myself.

    For designing buggy circuits?

    John
     
  5. I prefer "Not Pointing iN" for NPN
     
  6. Activ8

    Activ8 Guest

    On Wed, 09 Jun 2004 11:47:11 -0700, John Larkin wrote:
    Not a chance. See below. It points *toward* the n type emitter and
    *away from the p type base. I read that in black and white in 6th
    grade. My first (and highly addicting) electronics read. Today, I'm
    reading it again on the net. See below.
    Is that an IGBT above?. The thing you labeled "n-ch fet" which
    resembles no n-ch device symbol that *I've* ever seen.

    http://www.elec.gla.ac.uk/groups/dev_mod/papers/igbt/igbt.html

    ***
    http://www.powerdesigners.com/InfoWeb/design_center/articles/IGBTs/igbts.shtm

    "The circuit symbol for an n-channel IGBT, is shown in Fig. 2."
    ***

    The point is that it's n-ch and the mosfet in the equiv circuit is
    drawn with the MOSFET arrow pointing inward.

    http://www.web-ee.com/primers/files/IGBT.pdf

    http://www.tpub.com/neets/book7/26i.htm

    ******* HERE WE GO *******
    from google
    http://www.google.com/search?num=25&hl=en&lr=&ie=UTF-8&safe=off&q=transistor+symbol

    "Field Effect Transistors... within the symbol. Just as it does in
    transistor symbols, the arrow in a JFET symbol always points towards
    the N-type material. ...
    www.tpub.com/neets/book7/26i.htm - 21k "
    ***************************

    :-O Had enough?
    A MOSFET's gate is one plate of a cap, that's why it's drawn that
    way.
    That's good. The above was unmodified andy's ascii art.
    But you're not trying to say it's a p-ch device here, as you do
    below.
    The substrate or body diode *is* drawn. It's in the middle notice
    it's pointing toward the n-channel?

    Compare it to a diode

    --->|---

    the arrow points to the n-type cathode. SCR... same damn thing.

    You can draw the zener for power MOSFET so it's obvious it's a POWER
    device. Look at a spec sheet.
    See links above.
    So the OP will be FUBAR.
    I don't drive a buggy ;)
     
  7. Rich Grise

    Rich Grise Guest

    Not Pointing iN.

    :)
    Rich
     
  8. Ben Bradley

    Ben Bradley Guest

    That's how I heard it from my eigth grade electronics teacher, and
    PNP was Pointing iN Proudly.
    Perhaps a public [Government] high school teacher in 1970 didn't
    want to use a phrase that had piss in it, presuming he even knew it -
    I've had a career in electronics, and I've never heard Pissin 'N a
    Platter.
     
  9. Bob Stephens

    Bob Stephens Guest

    Me neither. I always heard Point iN Please, and Not Pointing In.
     
  10. John Larkin

    John Larkin Guest

    How about "the current flows in the direction of the arrow"?

    John
     
  11. K Williams

    K Williams Guest

    That's how I remembered it, at least before college. Then we
    learned it was the PN diode, like a diode. I think I was a senior
    when I was told it *really* was Piss-N-Pot. ;-)
     
  12. starfire

    starfire Guest

    Not Pointing iN and Point oN Plate.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-