मराठी
महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

Why is the base of a transistor made thin and is lightly doped? - Physics

Advertisements
Advertisements

प्रश्न

Why is the base of a transistor made thin and is lightly doped?

थोडक्यात उत्तर

उत्तर

The base of a transistor is lightly doped than the emitter and narrowed so that almost all electrons injected from the emitter (in a n-p-n transistor) diffuse right across the base to the collector junction without recombining with holes. In other words, the base width is kept smaller than the recombination distance. In addition, to improve emitter efficiency and common-base current gain α, the emitter is much more heavily doped than the base.

shaalaa.com
Bipolar Junction Transistor (BJT)
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 16: Semiconductor Devices - Exercises [पृष्ठ ३६३]

APPEARS IN

बालभारती Physics [English] 12 Standard HSC Maharashtra State Board
पाठ 16 Semiconductor Devices
Exercises | Q 2.1 | पृष्ठ ३६३

संबंधित प्रश्‍न

In a common base configuration, the transistor has an emitter current of 10 mA and a collector current of 9.8 mA. The value of base current is ______ 


Draw the circuit symbol of the PNP transistor. 


For a transistor IC = 15 mA, IB = 0.5 mA. What is the current amplification factor?  


With the help of a neat diagram, explain the working of the npn transistor?  


With the help of a neat circuit diagram, explain the transistor as an amplifier? 


The light emitted in an LED is due to


Explain the current flow in an NPN transistor.


Explain the need for a feedback circuit in a transistor oscillator.


Assuming VCEsat = 0.2 V and β = 50, find the minimum base current (IB) required to drive the transistor given in the figure to saturation.


A transistor of α = 0.99 and VBE = 0.7 V is connected in the common-emitter configuration as shown in the figure. If the transistor is in the saturation region, find the value of collector current.


In the circuit shown in the figure, the BJT has a current gain (β) of 50. For an emitter-base voltage VEB = 600 mV, calculate the emitter-collector voltage VEC (in volts).


ln switching circuit, transistor is in ON state and values of IC and IB are 4.2 mA and 5 µA respectively and RC= l k`Omega` and RB= 300 k`Omega`. If VBE = 0.5 V, find the value of VBB.


In switching circuit, transistor is in ON state, values of IE and lB are 10 mA and 0.8 mA respectively and RL is 2 k`Omega`. If VCE is 7.6 V, then VCC is ____________.


In an npn transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector, the emitter current (IE) and base current (IB) are given by ____________.


In a silicon transistor, a change of 7.89 mA in the emitter current if produces a change of 7.8 mA in the collector current, then the base current must change by ____________.


In a transistor, a change of 8.0 mA in the emitter current produces a change of 7.8 mA in the collector current. Then change in the base current is ____________.


A transistor when connected in common emitter mode has a ____________.


A change of 9.0 mA in the emitter current brings a change of 8.9 mA in the collector current. The value of current gain β will be ______.


For an ideal diode, the current in the following arrangement is ______.


In common emitter amplifier, a change of 0.2 mA in the base current causes a change of 5 mA in the collector current. If input resistance is 2K `Omega` and voltage gain is 75, the load resistance used in the circuit is ______.


A transistor having α = 0.8 is connected in a common emitter configuration. When the base current changes by 6 mA, the change in collector current is ______ 


A conducting wire has length 'L1' and diameter 'd1'. After stretching the same wire length becomes 'L2' and diameter 'd2' The ratio of resistances before and after stretching is ______.


For a transistor,  αdc and βdc are the current ratios, then the value of `(beta_"dc"-delta_"dc")/(alpha_"dc".beta_"dc")` 


The collector current in a common-emitter transistor amplifier is 4 mA. When the base current is increased by 20 µA, the collector current increases to 6 mA. The current gain is ______.


How is a transistor biased for operating it as amplifier?


In a CE amplifier, the current gain is 80 and the emitter current is 9 mA. The base current is ______.


Define peak value of alternating signal.


Explain the output characteristics of common emitter configuration of n-p-n transistor.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×