October 17th was a very, very special day as exactly 100 years ago, Lee
de Forest
(1873-1961) wrote the patent for 'Device for amplifying feeble
electrical
currents', later to be known as the TRIODE!

The patent was filed 25 October 1906 and granted 15 January 1907.

You can find a copy of the patent here (US Patent Office):
http://makeashorterlink.com/?N2EA32BFD

The part I like:
'My invention relates to devices for amplifying feeble electrical
currents -
such, for example, as telephone-currents; and its object is to produce
an
amplifying device of greater efficiency and simplicity than those
heretofore
employed.'

And this one says it all:
'In a device for amplifying electrical currents, an evacuated vessel,
three
electrodes sealed within said vessel, means for heating one of said
electrodes, a local receiving-circuit including two of said electrodes,
and
means for passing the current to be amplified between one of the
electrodes
which is included in the receiving-circuit and the third electrode.'

The (hand-drawn) drawings are cool too.

Notice that LdF placed the grid on one side of the heater and the anode
on
the other side of the heater. It took him a couple of months to figure
out
that things worked better with the grid between the heater and the
anode (as
can be seen in a later LdF patent).

Andy Evans wrote:


Notice that LdF placed the grid on one side of the heater and the anode
on
the other side of the heater. It took him a couple of months to figure
out
that things worked better with the grid between the heater and the
anode (as
can be seen in a later LdF patent).


Interesting (and pointless) idea, with the grid like that, I expect you
would need to drive the grid positive to prevent current flow.

--
Nick

In article .com, Andy
Evans writes
October 17th was a very, very special day as exactly 100 years ago, Lee
de Forest
(1873-1961) wrote the patent for 'Device for amplifying feeble
electrical
currents', later to be known as the TRIODE!

The patent was filed 25 October 1906 and granted 15 January 1907.

You can find a copy of the patent here (US Patent Office):
http://makeashorterlink.com/?N2EA32BFD

The part I like:
'My invention relates to devices for amplifying feeble electrical
currents -
such, for example, as telephone-currents; and its object is to produce
an
amplifying device of greater efficiency and simplicity than those
heretofore
employed.'

And this one says it all:
'In a device for amplifying electrical currents, an evacuated vessel,
three
electrodes sealed within said vessel, means for heating one of said
electrodes, a local receiving-circuit including two of said electrodes,
and
means for passing the current to be amplified between one of the
electrodes
which is included in the receiving-circuit and the third electrode.'

The (hand-drawn) drawings are cool too.

Notice that LdF placed the grid on one side of the heater and the anode
on
the other side of the heater. It took him a couple of months to figure
out
that things worked better with the grid between the heater and the
anode (as
can be seen in a later LdF patent).

I should think that our Keith will be worshipping at the fundamental
orifice of St Agnes on hearing that news
--
Tony Sayer

"tony sayer" wrote in message
...
In article .com, Andy
Evans writes
October 17th was a very, very special day as exactly 100 years ago, Lee
de Forest
(1873-1961) wrote the patent for 'Device for amplifying feeble
electrical
currents', later to be known as the TRIODE!

The patent was filed 25 October 1906 and granted 15 January 1907.

You can find a copy of the patent here (US Patent Office):
http://makeashorterlink.com/?N2EA32BFD

The part I like:
'My invention relates to devices for amplifying feeble electrical
currents -
such, for example, as telephone-currents; and its object is to produce
an
amplifying device of greater efficiency and simplicity than those
heretofore
employed.'

And this one says it all:
'In a device for amplifying electrical currents, an evacuated vessel,
three
electrodes sealed within said vessel, means for heating one of said
electrodes, a local receiving-circuit including two of said electrodes,
and
means for passing the current to be amplified between one of the
electrodes
which is included in the receiving-circuit and the third electrode.'

The (hand-drawn) drawings are cool too.

Notice that LdF placed the grid on one side of the heater and the anode
on
the other side of the heater. It took him a couple of months to figure
out
that things worked better with the grid between the heater and the
anode (as
can be seen in a later LdF patent).

I should think that our Keith will be worshipping at the fundamental
orifice of St Agnes on hearing that news



No, he's just been over the town to worship at the financial orifice of St
Argos for a couple of shaver plug adaptors at 2.99 apiece, but swung a right
to Stable Cables* instead and got them for 98p+ VAT apiece....

....then got stoked on a couple of 'multiple socket' extension leads that had
'surge protection' I didn't intend paying the extra for....

....and totally forgot to grab some sodding slow-blow fuses while I wuz in
there....!!

:-[


* Wooden-fronted, trade 'Tardis' for all things lecky - they do have got
*the lot* in there!!