This was the first very crude seed to the modern society we know today.
Edison did some experiments with glowing cathodes in vacuum and
found that current could run in vacuum without any metal wire .
His efforts were to improve the incandesent light. However he did
never fully realized the potential of elecrons that could run in the
vacuum. Well, the electron wasn´t even discovered yet and
Edison did never patent it. In 1897 the first fundamental building
block of nature was discovered by J J Thomson, the electron were born.
In 1904 John Fleming invented the first real electronic device wich e
patented. The vacuum diode valve. Later in 1906 De Forest
put in a gate in the diode and the audio amplifier were born. The
impact of these discoveries is monumental.
A simple vacuum diode is very easy to make. The vacuum from a
rotary pump is enough to get enough mean free path o the electrons in the vacuum space
for a couple of mm. A bell jar made from a wine glass and inside a
glowing cathode taken from a low voltage (12v) halogen lamp can
beused. A wire grid is used as anode. When the chatode glow, the
elecrons can only run from the hot cathode to the anode, not vice versa.
a simple rectifying vacuum diode the fleming way.
