Thermionic Overunity Generator my gift to the world.

[MarkE]

Why not simply use undisturbed diode arrays?

Because in 1958 Brillioun proved that cannot work.

[telecom]

Thank you for the gift! How arises the "free energy"? And what is the working principle?

Thoriated filament decreases the work function of the tube, this is well known.
Thorium is an alpha emitter.
Alpha particles bombard negatively charged filament which emits electrones.
The rest works as a linear accelerator

[pomodoro]

Now I wish I kept the 4-400s I had in storage for years!  Looks like Arthur's team managed to suck electrons out from the aether using the humble vacuum tube. So that is the real reason for transistorization! To stop us once again from OU!

[lumen]

This is not much different from the old "Nuclear Battery"
You know the tiny isolated sphere inside a larger evacuated sphere.
The small sphere is covered with radium and when electrons are ejected they are captured on the outer sphere.
It produces small current with high voltage around 100 watts.

I would think the same thing would work with a thoriated tungsten filament or any heated thoriated tungsten as the emitter.

[pomodoro]

I can't see the electrons actually having enough momentum to strike the plate.