With a change of load resistance of a triode, | vedclass

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(A) The voltage amplification $A_v$ of a triode amplifier is given by the formula: $A_v = \frac{\mu}{1 + \frac{r_p}{R_L}}$, where $\mu$ is the amplifi

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$25$

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(A) The voltage amplification $A_v$ of a triode amplifier is given by the formula: $A_v = \frac{\mu}{1 + \frac{r_p}{R_L}}$, where $\mu$ is the amplification factor, $r_p$ is the plate resistance, and $R_L$ is the load resistance.For the first case: $25 = \frac{\mu}{1 + \frac{r_p}{50}}$ (where $r_p$ and $R_L$ are in $k\Omega$).$\Rightarrow \mu = 25 \left(1 + \frac{r_p}{50}\right) = 25 + 0.5 r_p$......$(i)$For the second case: $30 = \frac{\mu}{1 + \frac{r_p}{100}}$.$\Rightarrow \mu = 30 \left(1 + \frac{r_p}{100}\right) = 30 + 0.3 r_p$......$(ii)$Equating $(i)$ and $(ii)$:$25 + 0.5 r_p = 30 + 0.3 r_p$$0.2 r_p = 5$$r_p = \frac{5}{0.2} = 25 \, k\Omega$.

With a change of load resistance of a triode, used as an amplifier, from $50 \, k\Omega$ to $100 \, k\Omega$, its voltage amplification changes from $25$ to $30$. The plate resistance of the triode is.....$k\Omega$.

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