I have got the following doubt. Hope you clarify it. Thanks in advance

electron when finishes its life time recombines with hole in valence band . its given that in an pnp transistor holes of emitter recombine with electrons of base to give base current. How does recombination give current ?

I mean current is produced due to movement of electrons in CB (conduction band) or holes in VB(valence band). So how does this recombination produce current?


The electron and hole come from neutral atoms. In order to restore neutrality in the semiconductor material an electron has to be brought in from or ejected to the external circuit. This motion of electrons is called current.

  • \$\begingroup\$ I didn't mean that....in the textbook i had gone through...base current is produced due to recombination...but how...because ww need mobile electrons \$\endgroup\$ – Siva Tarun Ponnada Dec 30 '15 at 4:33
  • \$\begingroup\$ If you have a specific passage you want to bring into question then you need to either cite it or quote it in the question. \$\endgroup\$ – Ignacio Vazquez-Abrams Dec 30 '15 at 4:37

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