The plate current i_p in a triode valve is gi | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) Given: $i_p = K(V_p + \mu V_g)^{3/2}$,$r_p = 10^4 \, \Omega$,$g_m = 5 	imes 10^{-3} \, 	ext{mho}$.First,calculate the amplification factor $\mu

Vedclass · Accepted Answer

$-6 \, V, (1/30)^{3/2}$

Vedclass · Answer

(B) Given: $i_p = K(V_p + \mu V_g)^{3/2}$,$r_p = 10^4 \, \Omega$,$g_m = 5 	imes 10^{-3} \, 	ext{mho}$.First,calculate the amplification factor $\mu = r_p 	imes g_m = 10^4 	imes 5 	imes 10^{-3} = 50$.For the grid cut-off voltage,$i_p = 0$,so $V_p + \mu V_g = 0$. Thus,$V_g = -V_p / \mu = -300 / 50 = -6 \, V$.Now,differentiate $i_p$ with respect to $V_g$ to find $g_m$: $g_m = \frac{\partial i_p}{\partial V_g} = K \cdot \frac{3}{2} (V_p + \mu V_g)^{1/2} \cdot \mu$.At the given operating point,$i_p = 8 \, mA$,so $8 = K(V_p + \mu V_g)^{3/2} \implies (V_p + \mu V_g)^{1/2} = (8/K)^{1/3}$.Substituting this into the $g_m$ equation: $5 	imes 10^{-3} = \frac{3}{2} K \mu (8/K)^{1/3} = \frac{3}{2} 	imes 50 	imes K^{2/3} 	imes 2 = 150 K^{2/3}$.Note: Since $i_p$ is in $mA$,$g_m$ is in $mA/V$. $5 	imes 10^{-3} \, 	ext{mho} = 5 \, mA/V$.$5 = 150 K^{2/3} \implies K^{2/3} = 5/150 = 1/30 \implies K = (1/30)^{3/2}$.

Similar Questions

The relation between $I_p$ and $V_p$ for a triode is $I_p = (0.125V_p - 7.5) \text{ mA}$. Keeping the grid potential constant at $1 \text{ V}$,the value of $r_p$ will be . . . . . . $\text{k}\Omega$.

The plate resistance of a triode is $2.5 \times 10^{4} \ \Omega$ and mutual conductance is $2 \times 10^{-3} \ \text{mho}$. What will be the value of the amplification factor?

In a triode amplifier,$\mu = 25$,$r_p = 40 \text{ k}\Omega$,and load resistance $R_L = 10 \text{ k}\Omega$. If the input signal voltage is $0.5 \text{ V}$,then the output signal voltage will be.....$\text{V}$.

The relation between dynamic plate resistance $(r_p)$ of a vacuum diode and plate current $(I_p)$ in the space charge limited region is:

The amplification factor of a triode is $50$. If the grid potential is decreased by $0.20\, V$,what increase in plate potential will keep the plate current unchanged?

Vedclass Test Series

Exam Paper Generator

Online Exam Module