Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12
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# A Triode Has Mutual Conductance of 2.0 Millimho and Plate Resistance of 20 Kω. It is Desired to Amplify a Signal by a Factor of 30. What Load Resistance Should Be Added in the Circuit? - Physics

ConceptTriode

#### Question

A triode has mutual conductance of 2.0 millimho and plate resistance of 20 kΩ. It is desired to amplify a signal by a factor of 30. What load resistance should be added in the circuit?

#### Solution

Plate resistance, rp = 20 kΩ
Mutual Conductance, g= 2.0 milli mho
g= 2 × 10−3 mho

Amplification factor, µ = 30
Load Resistance = RL = ?
We know:-

$A = \frac{\mu}{1 + \mathit{\frac{r_p}{R_L}}}$

where A is the voltage amplification factor.

Also, amplification factor,

mu=r_pxxg_m

$A = \frac{r_p \times g_m}{1 + \mathit{\frac{r_p}{R_L}}}$

On substitution of all the given values, we  get:-

$30 = \frac{20 \times {10}^3 \times 2 \times {10}^{- 3}}{1 + \frac{20000}{R_L}}$

$\Rightarrow 1 + \frac{20000}{R_L} = \frac{40}{30}$

$\frac{20000}{R_L} = \frac{1}{3}$

$\Rightarrow R_L = 60000 \Omega = 60 k\Omega$

Is there an error in this question or solution?

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Solution A Triode Has Mutual Conductance of 2.0 Millimho and Plate Resistance of 20 Kω. It is Desired to Amplify a Signal by a Factor of 30. What Load Resistance Should Be Added in the Circuit? Concept: Triode.
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