HSC Science (Computer Science) 12th Board ExamMaharashtra State Board
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# What Are α And β Parameters for a Transistor? Obtain a Relation Between Them. - HSC Science (Computer Science) 12th Board Exam - Physics

ConceptTransistor and Characteristics of a Transistor

#### Question

What are α and β parameters for a transistor? Obtain a relation between them.

#### Solution

Alpha (αdc): It is defined as the ratio of collector current to emitter current.

alpha_(dc)="I"_c/"I"_E -----------------(Equation 1)

Beta (βdc): It is the current gain defined as the ratio of collector current to the base current.

beta_(dc)="I"_c/"I"_B --------------------(Equation 2)

Relation between αdc and βdc:

For a transistor,

IE = IB + IC (with Ic ≅ IE) -----------(Equation 3)

Divinding both the side of eqn.(3) with Ic ,we get :

"I"_E/"I"_c="I"_B/"I"_C+1

1/alpha_(dc)=1/beta_(dc)+1

alpha_(dc)=beta_(dc)/(1+beta_(dc)) -----------------------(Equation 4)

Or, beta_(dc)=alpha_(dc)/(1-alpha_(dc)) ----------------------(Equation 5)

Equations (4) and (5) give the relation between αdc and βdc of a transistor.

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#### APPEARS IN

2014-2015 (March) (with solutions)
Question 7.2 | 3.00 marks

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Solution What Are α And β Parameters for a Transistor? Obtain a Relation Between Them. Concept: Transistor and Characteristics of a Transistor.
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