Determine all JFET currents and voltages if the source curre

Determine all JFET currents and voltages if the source current is 2.6 mA Determine all JFET currents and voltages if Vgs = -1.6V

Solution

A)

V_G = (V_DD X R_g2) / (R_g1+R_g2) = (20 X 0.8M) / (3.5M + 0.8M) = 3.721 V

I_G = 0 A,  I_S = 2.6 mA , I_D = I_S = 2.6 mA

V_S = R_SI_S = 2 X 10⁺³ X 2.6 X 10^-3 = 5.2 V

V_GS = V_G - V_S = 3.721 - 5.2 = -1.479 V

V_D = V_DD -I_DR_D = 20 - (2.6x3.3) = 11.42 V

B)

V_GS = -1.6 V

V_G = (V_DD X R_g2 ) / (R_g1 + R_g2) = (16 X 0.4M) / (2M+0.4M) = 2.667 V

V_S = V_G - V_GS = 2.667 - (-1.6) = 4.267 V

I_G = 0 A , I_S = I_D = (V_S/R_D) = 4.267/1.8 = 2.371 mA

V_D = V_DD - I_DR_D = 16 - (2.371 X 3.9) = 6.753 V