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How to tell if a BJT is PNP or NPN by looking at the circuit?


What's the difference between NPN and PNP transistors?Using an NPN vs a PNP transistorWhy are the current directions in the hybrid-$pi$ model for BJT the same for both NPN and PNP?Help with NPN and PNP common emitterApplying hybrid-pi model of an npn-BJT to a pnp BJT in small signal analysisWhat's the differences of these usage of PNP, NPN transistors?PNP and NPN Collector Emitter namingBJT NPN current flowHow do I implement a DPDT-switch here using NPN/PNP instead?PNP BJT small signal model













2












$begingroup$


enter image description here



enter image description here



Is it possible to tell if a BJT circuit is PNP or NPN simply by looking at the circuit?



For example, for the circuits shown, how can we tell if they're PNP or NPN?










share|improve this question







New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$












  • $begingroup$
    Yes. Look at the location/direction of the arrow. That is really a question for your textbook or a search engine.
    $endgroup$
    – Eugene Sh.
    1 hour ago








  • 3




    $begingroup$
    I'm voting to close this question as off-topic because there is no evidence of effort to research this answer at all.
    $endgroup$
    – Andy aka
    1 hour ago










  • $begingroup$
    A memory aid: emmiter arrow on an NPN is Not Pointing iN
    $endgroup$
    – Peter Bennett
    1 hour ago










  • $begingroup$
    Another memory aid that has stuck with me for a while: PNP is Pointing iNward Proudly
    $endgroup$
    – Andrey Akhmetov
    30 mins ago
















2












$begingroup$


enter image description here



enter image description here



Is it possible to tell if a BJT circuit is PNP or NPN simply by looking at the circuit?



For example, for the circuits shown, how can we tell if they're PNP or NPN?










share|improve this question







New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$












  • $begingroup$
    Yes. Look at the location/direction of the arrow. That is really a question for your textbook or a search engine.
    $endgroup$
    – Eugene Sh.
    1 hour ago








  • 3




    $begingroup$
    I'm voting to close this question as off-topic because there is no evidence of effort to research this answer at all.
    $endgroup$
    – Andy aka
    1 hour ago










  • $begingroup$
    A memory aid: emmiter arrow on an NPN is Not Pointing iN
    $endgroup$
    – Peter Bennett
    1 hour ago










  • $begingroup$
    Another memory aid that has stuck with me for a while: PNP is Pointing iNward Proudly
    $endgroup$
    – Andrey Akhmetov
    30 mins ago














2












2








2





$begingroup$


enter image description here



enter image description here



Is it possible to tell if a BJT circuit is PNP or NPN simply by looking at the circuit?



For example, for the circuits shown, how can we tell if they're PNP or NPN?










share|improve this question







New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




enter image description here



enter image description here



Is it possible to tell if a BJT circuit is PNP or NPN simply by looking at the circuit?



For example, for the circuits shown, how can we tell if they're PNP or NPN?







bjt






share|improve this question







New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question






New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 1 hour ago









Jimmy VailerJimmy Vailer

355




355




New contributor




Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Jimmy Vailer is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












  • $begingroup$
    Yes. Look at the location/direction of the arrow. That is really a question for your textbook or a search engine.
    $endgroup$
    – Eugene Sh.
    1 hour ago








  • 3




    $begingroup$
    I'm voting to close this question as off-topic because there is no evidence of effort to research this answer at all.
    $endgroup$
    – Andy aka
    1 hour ago










  • $begingroup$
    A memory aid: emmiter arrow on an NPN is Not Pointing iN
    $endgroup$
    – Peter Bennett
    1 hour ago










  • $begingroup$
    Another memory aid that has stuck with me for a while: PNP is Pointing iNward Proudly
    $endgroup$
    – Andrey Akhmetov
    30 mins ago


















  • $begingroup$
    Yes. Look at the location/direction of the arrow. That is really a question for your textbook or a search engine.
    $endgroup$
    – Eugene Sh.
    1 hour ago








  • 3




    $begingroup$
    I'm voting to close this question as off-topic because there is no evidence of effort to research this answer at all.
    $endgroup$
    – Andy aka
    1 hour ago










  • $begingroup$
    A memory aid: emmiter arrow on an NPN is Not Pointing iN
    $endgroup$
    – Peter Bennett
    1 hour ago










  • $begingroup$
    Another memory aid that has stuck with me for a while: PNP is Pointing iNward Proudly
    $endgroup$
    – Andrey Akhmetov
    30 mins ago
















$begingroup$
Yes. Look at the location/direction of the arrow. That is really a question for your textbook or a search engine.
$endgroup$
– Eugene Sh.
1 hour ago






$begingroup$
Yes. Look at the location/direction of the arrow. That is really a question for your textbook or a search engine.
$endgroup$
– Eugene Sh.
1 hour ago






3




3




$begingroup$
I'm voting to close this question as off-topic because there is no evidence of effort to research this answer at all.
$endgroup$
– Andy aka
1 hour ago




$begingroup$
I'm voting to close this question as off-topic because there is no evidence of effort to research this answer at all.
$endgroup$
– Andy aka
1 hour ago












$begingroup$
A memory aid: emmiter arrow on an NPN is Not Pointing iN
$endgroup$
– Peter Bennett
1 hour ago




$begingroup$
A memory aid: emmiter arrow on an NPN is Not Pointing iN
$endgroup$
– Peter Bennett
1 hour ago












$begingroup$
Another memory aid that has stuck with me for a while: PNP is Pointing iNward Proudly
$endgroup$
– Andrey Akhmetov
30 mins ago




$begingroup$
Another memory aid that has stuck with me for a while: PNP is Pointing iNward Proudly
$endgroup$
– Andrey Akhmetov
30 mins ago










3 Answers
3






active

oldest

votes


















6












$begingroup$

Quite simply, look at the arrow on the leg.



enter image description here



The arrow will always be on the emitter. Look at where the current flows. The arrow will always follow the current flow.



When the arrow is pointing away from the base, it is an NPN. When pointing towards the base, it is a PNP.






share|improve this answer









$endgroup$





















    3












    $begingroup$

    If the arrow points towards the base it is a PNP, if it points away from the base it is an NPN.



    Further, the arrow will typically be on the more positive leg for PNP and negative for NPN.






    share|improve this answer











    $endgroup$













    • $begingroup$
      Thank you. So would those all be PNP?
      $endgroup$
      – Jimmy Vailer
      1 hour ago










    • $begingroup$
      No. Look carefully.
      $endgroup$
      – Eugene Sh.
      1 hour ago










    • $begingroup$
      All but one....
      $endgroup$
      – evildemonic
      1 hour ago










    • $begingroup$
      Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
      $endgroup$
      – Jimmy Vailer
      1 hour ago










    • $begingroup$
      No. Look at the direction of the arrow with respect to the BASE of the transistor.
      $endgroup$
      – evildemonic
      1 hour ago



















    0












    $begingroup$

    This diagram should explain everything



    enter image description here



    Any additional questions?






    share|improve this answer









    $endgroup$













      Your Answer





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      3 Answers
      3






      active

      oldest

      votes








      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      6












      $begingroup$

      Quite simply, look at the arrow on the leg.



      enter image description here



      The arrow will always be on the emitter. Look at where the current flows. The arrow will always follow the current flow.



      When the arrow is pointing away from the base, it is an NPN. When pointing towards the base, it is a PNP.






      share|improve this answer









      $endgroup$


















        6












        $begingroup$

        Quite simply, look at the arrow on the leg.



        enter image description here



        The arrow will always be on the emitter. Look at where the current flows. The arrow will always follow the current flow.



        When the arrow is pointing away from the base, it is an NPN. When pointing towards the base, it is a PNP.






        share|improve this answer









        $endgroup$
















          6












          6








          6





          $begingroup$

          Quite simply, look at the arrow on the leg.



          enter image description here



          The arrow will always be on the emitter. Look at where the current flows. The arrow will always follow the current flow.



          When the arrow is pointing away from the base, it is an NPN. When pointing towards the base, it is a PNP.






          share|improve this answer









          $endgroup$



          Quite simply, look at the arrow on the leg.



          enter image description here



          The arrow will always be on the emitter. Look at where the current flows. The arrow will always follow the current flow.



          When the arrow is pointing away from the base, it is an NPN. When pointing towards the base, it is a PNP.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 1 hour ago









          MCGMCG

          6,33631747




          6,33631747

























              3












              $begingroup$

              If the arrow points towards the base it is a PNP, if it points away from the base it is an NPN.



              Further, the arrow will typically be on the more positive leg for PNP and negative for NPN.






              share|improve this answer











              $endgroup$













              • $begingroup$
                Thank you. So would those all be PNP?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look carefully.
                $endgroup$
                – Eugene Sh.
                1 hour ago










              • $begingroup$
                All but one....
                $endgroup$
                – evildemonic
                1 hour ago










              • $begingroup$
                Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look at the direction of the arrow with respect to the BASE of the transistor.
                $endgroup$
                – evildemonic
                1 hour ago
















              3












              $begingroup$

              If the arrow points towards the base it is a PNP, if it points away from the base it is an NPN.



              Further, the arrow will typically be on the more positive leg for PNP and negative for NPN.






              share|improve this answer











              $endgroup$













              • $begingroup$
                Thank you. So would those all be PNP?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look carefully.
                $endgroup$
                – Eugene Sh.
                1 hour ago










              • $begingroup$
                All but one....
                $endgroup$
                – evildemonic
                1 hour ago










              • $begingroup$
                Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look at the direction of the arrow with respect to the BASE of the transistor.
                $endgroup$
                – evildemonic
                1 hour ago














              3












              3








              3





              $begingroup$

              If the arrow points towards the base it is a PNP, if it points away from the base it is an NPN.



              Further, the arrow will typically be on the more positive leg for PNP and negative for NPN.






              share|improve this answer











              $endgroup$



              If the arrow points towards the base it is a PNP, if it points away from the base it is an NPN.



              Further, the arrow will typically be on the more positive leg for PNP and negative for NPN.







              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited 1 hour ago

























              answered 1 hour ago









              evildemonicevildemonic

              2,233720




              2,233720












              • $begingroup$
                Thank you. So would those all be PNP?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look carefully.
                $endgroup$
                – Eugene Sh.
                1 hour ago










              • $begingroup$
                All but one....
                $endgroup$
                – evildemonic
                1 hour ago










              • $begingroup$
                Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look at the direction of the arrow with respect to the BASE of the transistor.
                $endgroup$
                – evildemonic
                1 hour ago


















              • $begingroup$
                Thank you. So would those all be PNP?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look carefully.
                $endgroup$
                – Eugene Sh.
                1 hour ago










              • $begingroup$
                All but one....
                $endgroup$
                – evildemonic
                1 hour ago










              • $begingroup$
                Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
                $endgroup$
                – Jimmy Vailer
                1 hour ago










              • $begingroup$
                No. Look at the direction of the arrow with respect to the BASE of the transistor.
                $endgroup$
                – evildemonic
                1 hour ago
















              $begingroup$
              Thank you. So would those all be PNP?
              $endgroup$
              – Jimmy Vailer
              1 hour ago




              $begingroup$
              Thank you. So would those all be PNP?
              $endgroup$
              – Jimmy Vailer
              1 hour ago












              $begingroup$
              No. Look carefully.
              $endgroup$
              – Eugene Sh.
              1 hour ago




              $begingroup$
              No. Look carefully.
              $endgroup$
              – Eugene Sh.
              1 hour ago












              $begingroup$
              All but one....
              $endgroup$
              – evildemonic
              1 hour ago




              $begingroup$
              All but one....
              $endgroup$
              – evildemonic
              1 hour ago












              $begingroup$
              Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
              $endgroup$
              – Jimmy Vailer
              1 hour ago




              $begingroup$
              Oh so c) (the first one) would be NPN because the arrow above the current source is pointing away?
              $endgroup$
              – Jimmy Vailer
              1 hour ago












              $begingroup$
              No. Look at the direction of the arrow with respect to the BASE of the transistor.
              $endgroup$
              – evildemonic
              1 hour ago




              $begingroup$
              No. Look at the direction of the arrow with respect to the BASE of the transistor.
              $endgroup$
              – evildemonic
              1 hour ago











              0












              $begingroup$

              This diagram should explain everything



              enter image description here



              Any additional questions?






              share|improve this answer









              $endgroup$


















                0












                $begingroup$

                This diagram should explain everything



                enter image description here



                Any additional questions?






                share|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  This diagram should explain everything



                  enter image description here



                  Any additional questions?






                  share|improve this answer









                  $endgroup$



                  This diagram should explain everything



                  enter image description here



                  Any additional questions?







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 1 hour ago









                  G36G36

                  5,3901511




                  5,3901511






















                      Jimmy Vailer is a new contributor. Be nice, and check out our Code of Conduct.










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                      Jimmy Vailer is a new contributor. Be nice, and check out our Code of Conduct.













                      Jimmy Vailer is a new contributor. Be nice, and check out our Code of Conduct.












                      Jimmy Vailer is a new contributor. Be nice, and check out our Code of Conduct.
















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