ELECTRICAL THINGS

What is Bipolar junction transistor ?  Working of NPN Transistor Forward bias is applied to emitter-base junction and reverse bias is applied to collector base junction. Connection diagram of NPN transistor The forward bias in the emitter-base junction causes electrons to move toward base. This constitute emitter current, I E . As the electrons flow toward P-type base, they try to recombine with holes. As base is lightly doped only few electrons recombine with holes within the base. These recombined electrons constitute small base current, I B . The remainder electrons crosses base and constitute collector current.                                                  I E =I B + I C Working of PNP Transistor Forward bias is applied to emitter-base junction and reverse bias is applied to collector-base junction. Connection diagram of PNP transistor The forward bias in the emitter-base junction causes holes to move toward base. This constitute emitter current, I E . As the holes flow toward n

What is Bipolar Junction Transistor ?   Bipolar Junction Transistor The transistor is three-layer semiconductor device consisting of either two 'n-type' and one 'p-type' layers of material or two 'p-type' and one 'n-type' layers of material. The former is called as 'npn' , while latter is called as 'pnp' . So, there are two types of BJT -   npn-transister pnp-transister npn and pnp Transistor                                           In each transistor following points to be noted :-  There are two Junction, so transistor can be considered as two diode connected back to back. There are three terminals. The middle section is thinner than other. Naming of the Transistor terminal  Transistor has three section of dopped semiconductor. The section one side is called "emitter" and the opposite side is called "collector" and the middle section is called "base" , as shown in above figure. Emitter   The section one si

  What is P-N junction diode ? A  PN - junction diode  is formed when a p-type semiconductor is fused to an n-type semiconductor creating a potential barrier voltage across the  diode junction . A p–n junction is a boundary between two types of semiconductor materials, p-type and n-type, inside a single crystal of semiconductor. The "p" side contains an excess of holes, while the "n" side contains an excess of electrons in the outer shells of the electrically neutral atoms there. Types of P-N Junction diode  Forward bias p-n Junction  When an external voltage is applied to the P-N junction making the P side positive with respect to the N side the diode is said to be forward biased. The barrier potential difference is decreased by the external applied voltage. The depletion band narrows which urges majority carriers to flow across the junction. A Forward biased diode has a very low resistance. Reverse bias p-n Junction  When an external voltage is applied to the P-N