Is the electric potential near the grid uniform when grid is floating?

In other words is grid wire potential the same as grid space potential?


In other words is the potential at the grid wire the same as the potential between 2 adjacent grid (turns) wires?


Not sure. It may be so.


Would an electrometer measuring the grid measure the space potential at grid since due to its very very high input Z would not disturb the electric field?


For example when the 1H4 grid was left open and the anode was connected to 9V the field penetration of the positive anode to grid made the grid less negative by a few hundred millivolts. This was measured with a high Z voltmeter between grid and cathode.


The grid space potential was made less negative.


It had become negative as soon as 1.3V heater voltage was applied due to electron emission velocity, space charge near grid, missing electrons from the cathode which had become positive etc?


After applying 9V at plate the potential measured at the grid pin was less negative. The electron tube could operate with floating or open grid and only 9V at the anode. The sound was big. Anode current was only of the order of 10μA. The Pleiades V6 schematic was used:





See relevant 1H4 connected to mic post.


On the other hand Armstrong on his experiment observes that the mere presence of an unconnected grid seriously reduces plate or wing current compared to a diode [Armstrong]. Do a few electrons with enough initial velocity from cathode hit the grid and migrate to it? Or is it negative charge by induction?


The question remains, is grid space potential uniform when grid is free or open?


Next day's addition. Figures on the chapter containing grid and the island effect [Deketh] the potential around grid looks much more uniform when grid is not potential manipulated, externally biased, to toomnegative values.


Reference:


Operating features of the Audion - E. H. Armstrong


Fundamentals of radio-valve technique - Daketh - Philps Technical Library