6SN7 phase splitter , diff. amp. ground grid
RL = 270V/10mA = 27K
วงสวิง = 260-69 = 191V
กริดสวิง = 14V
Av = 191/14 = 13.6
กึ่งกลางวงสวิง = 260+69/2 = 164.5V
เลือก Vp = 169V
Vg -6V
Ia 3.7mA
Ik = 2*Ia = 2*3.7 = 7.4mA
Rk = 6V/7.4mA = 810R = 820R
Rp = 182-150V/4.9-2mA = 32/2.9 = 11V/mA = 11K
RL/Rp = 27K/11K = 2.5
Gm = 9-1mA/8-4V = 8/4 = 2mA/V
u = Gm*Rp = 2*11 = 22
Rp eff. = Rp+0.82K(u+1) = 11K+0.82K(22+1) = 11K+18.9K = 29.9K = 30K
gain = u*RL/Rp eff.+RL = 22*27K/30K+27K = 594K/57K = 10.4
แบ่งเกนกันซีกละครึ่ง = 5.2
B2+ = 6+169+(3.7mA*27K) = 175+99.9 = 274.9V
Vp gnd. = 175V