https://quentron.wordpress.com/The £10 Valve Experiment
Posted on December 19, 2012 by quentron
I have been asked (hi Mr S) to give some more detail to the original Philips E180F experiment that was carried out.
The output of current doubled when we paralleled 2 devices, the voltage double when we series connected.
The output increased exponentially in keeping with thermionic emission laws however there was a deviation from the simplistic Richardson equation.
All leads were shielded.
Experiments were repeated dozens of times in all, all results were in agreement with each other and with the underlying theory.
The experiment was designed intrinsically to have a very tight delta T and measurments by differential thermocouple means guaranteed that a delta T across the device was less than 0.1K. This is actually quite easy to achieve when you use the right combinations of thermal insulators and conductors, in fact by using polished inner metal device holders I calculate that we could even repeat this with mK control. However it is worth noting that no variance of output was observed even when deliberate delta T forcing was introduced that was greater than the required experimental stability.
A mechanical moving coil micro-ammeter was used once the current became significant, initially at starting pA levels through to 100nA a Keithley picometer was used.
The current was almost identical between devices (less than 10% variance)
Open circuit voltage reached a maximum of 875mV just before the device imploded.
For the used valve the maximum current obtained was a little under 10uA when done under vacuum.
The experiment repeated at an independent lab using a different pentode obtained 10uA.
