Find the values of r p , μ and g m of a triode operating at plate voltage 200 V and grid voltage –6 V. The plate characteristics are shown in figure.

Question

Philoid · Accepted Answer

The dynamic resistance of triode is defined as,

where ΔV_p is the change in plate voltage and V_g is the grid voltage and ΔI_p is the change in plate current

From figure, considering the line V_g=-6 V, we get two value of V_P i.e.

V_P1=160 V , V_P2=240 V , Also i_p1=3 mA i_p2=13mA

Substituting values in equation we get,

The mutual inductance g_m of a triode valve is defined as

Considering two points in the graph where V_p=200 V we get i_p1=13 mA i_p2=3mA V_g1=-4 V, V_g2=-8 V

Substituting values in equation we get.