A triode valve operates at Vp = 225 V and Vg = –0.5 V. The plate current remains unchanged if the plate voltage is increased to 250 V and the grid voltage is decreased to –2.5 V. Calculate the amplification factor.

Given VP1=225 V, VP2=250 V, Vg1=-0.5, Vg2=-2.5 V


where VT is the change in plate voltage and VT is the change in grid voltage




1