Fortress Technologies An E1T Timepiece, Руководство пользователя

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symbol for the tube, as used in circuits, is
shown in Fig. 5.3 with the connections to the
B12A base.
Some of the less important electrodes which
have no external connection are not shown in
this symbol. Sometimes g
3
and g
5
are also
omitted from the symbol. The electron beam is
formed at the rectangular shaped cathode, k,
the front of which is covered with an electron
emissive oxide coating. The beam flows
through the control grid, g
1
, past the beam
forming electrodes, b, and is then accelerated
through the electrode g
2
. These electrodes
focus the beam and also give it the desired
rectangular cross section which resembles a
piece of thick ribbon placed in a vertical plane.
The beam is then deflected by the deflector
plates, x' and x", into one of the ten stable
positions. The electrodes g
3
and g
5
are suppressor grids which are internally connected to the
cathode to prevent any unwanted effects which might be caused by secondary electron emission
from g
4
or from the anode, a
2
. The electrode g
4
has slots of the shape shown in Fig. 5.4. As will be
shown later, it can be arranged that the electron beam will be stable only when a certain fraction
of it is passing through one of the vertical rectangular slots in g
4
. The purpose of the horizontal
slot will be discussed later. The beam then travels to the anode, a
2
. A portion of it passes through
the anode to the fluorescent target, t. This target is covered with a conductive coating which is
connected to the positive H.T. supply line so as to prevent the accumulation of negative charge
from the electron beam which might disturb the operation of the tube. The electrode a
l
is the
reset anode. When the tube is indicating the digit 'nine' and a further pulse is received, the beam
is deflected by the plates x' and x" so that it strikes the reset anode; the mechanism by which the
tube is reset is then initiated by the fall of the reset anode potential. The auxiliary anode, aux, is
internally connected to the accelerating electrode, g
2
, and is employed to capture undesired
stray electrons. The screen s is internally connected to the cathode.
Page 113 Version 1.0 Copyright Grahame Marsh/Nick Stock 2019
Fig 5.2 - The Electrode Structure of the E1T
Fig 5.3 - The Symbol for the E1T; the Numbers
Indicate the Base Connections
Fig 5.4 - The g4 Electrode Showing the One
Horizontal and Ten Vertical Slots