A triode valve operates with V_p = 225 V and V_g = -0.5 V . If the plate voltage is raised to 250 V and the grid voltage is lowered to -2.5 V , the plate current is found to remain unaltered. Evaluate the amplification factor.

Step-by-step solution

The amplification factor of a triode is given by the ratio of the change in plate voltage to the change in grid voltage, keeping the plate current constant. = - ( V_p V_g )_ I_p = 0 Given V_ p1 = 225 V , V_ g1 = -0.5 V and V_ p2 = 250 V , V_ g2 = -2.5 V . Change in plate voltage, V_p = V_ p2 - V_ p1 = 250 - 225 = 25 V Change in grid voltage, V_g = V_ g2 - V_ g1 = -2.5 - (-0.5) = -2.0 V Substituting the values: = - ( 25 -2.0 ) = 12.5