Electrical Engineering ⇒ Topic : Tube Parameters

TUBE PARAMETERS

The following parameters are generally used:

Amplification factor μ

The ratio of small change in plate potential Δe_p to corresponding small change in grid potential Δe_g at a constant plate current is called the amplification factor.

                                                                 ............. (1)

There is no unit of amplification factor. The significance of negative sign is that to keep plate current constant, the grid potential must be decreased for increase in plate potential and vice versa.

Plate resistance

The plate resistance for the flow of direct current is different from the plate resistance due to the flow of alternating current

DC plate resistance: The ratio of steady plate potential to steady plate current is called DC plate resistance.

AC or dynamic plate resistance: The ratio of small change in plate potential Δe_p to the corresponding small change in plate current Δi_p keeping grid potential Δe_g constant is called AC dynamic plate resistance

                                                        ............ (2)

Its unit is ohm.

Mutual or transconductance: The ratio of small change in plate current Δi_p to the small change in grid potential Δe_g keeping plate potential constant is called mutual or transconductance g_m.

                                                           ................(3)