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

Explanation

Here , ` r_p = 20K Omega `
` = Plate resistance `
` Mutual Conductance = g_m `
`=2.0 milli mho
`=2xx10^(-3) mho
Amplification factor ,mu =30
Load Resistance =R_L = ?
` We know A = (mu/(1+r_p/R_L))`
` Where A =Voltage Amplification factor. `
` A = ((r_p xx g_m)/(1+(r_p/R_L)))`
` Where mu= r_p xx g_m `
` rArr 30 = ((20 xx (10^3) xx 2 xx (10^-3))/(1+20000/R_L))`
` rArr 3 =(4R/(R_L + 20000))`
` rArr 3R_L + 60000= 4R_L `
` R_L = 60000 Omega = 60Omega. `