The grid space potential increases when anode voltage is applied

There is a mistake on the previous recent posts.


When no anode (plate) supply but only heater is supplied to the 1H4 the free grid potemtial becomes approx -150mV to -250mV wrt cathode. )The value must depend on heater voltage variations, ie cathode electron emitting temperature). Possible cause missing electrons from the emoting cathode.


When 9V are applied to the plate (see Pleiades V6 1H4 experiments) anode current is 10μA and the potential of the grid becomes +50mV. In fact if we take 0 volts the average value of the filament which is between 0V and 1.3V by the filament supply battery... The bias increases from -850mV to -600mV. Why?


A possible reason is that we have 2 or 3 effects superimposed. The negative self bias by the missing electrons from the cathode. The potential distribution along the axis from from 0V cathode, grid to 9V plate when 9V are applied to it. A third cause may be the anode that is now attracting electrons reducing space charge?