Question

In the circuit shown here the transistor used has a current gain of hundred what should be base resistor so that voltage across emitter collector is 5 volt and voltage across base emitter is zero volt

Answer 1

Given:

• Transistor  has a current gain ${\beta} = 100$

• $V_{CE} =5V$

To Find:

• What should be the bias resistor $R_B$

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Solution:

Circuit for is attached below

Applying Kirchhoff's law to mesh ADCEFA

        $V_{CC}= 10 =I_C \times 10^3 + V_{CE}$

        $10=I_C \times 10^3+5\\I_C = 5 \times 10^{-3}A .......(i)$

Applying Kirchhoff's law to mesh AGBEFA

      $I_B \times R_B+V _{BE} =V_{CC} =10V$

      $I_B\times R_B +0 =10 ........(ii)$

       $5 \times 10^{-5} \times R_B =10$

       $R_B=2 \times 10^5\Omega$

        $R_B=200 \times 10^3\Omega$

Thus, The bias resistor  $R_B=200 \times 10^3\Omega$

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