What is the beta current ratio of a transistor?

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RRB ALP CBT 2 Electronic Mechanic Previous Paper: Held on 23 Jan 2019 Shift 1
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  1. IC/IB
  2. IB/IE 
  3. IE/IC 
  4. IC/IE

Answer (Detailed Solution Below)

Option 1 : IC/IB
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Detailed Solution

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The common-emitter current gain (β) is the ratio of the transistor's collector current to the transistor's base current, i.e.

And the common base DC current gain (α) is a ratio of the transistor's collector current to the transistor's emitter current, i.e.

The transistor currents are related by the relation:

IE = IB + IC

α can now be written as:

Dividing both the numerator and denominator by IB, we get:

Since 

 'or'

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