by the MODE switch. With the MODE switch
in
the
A ONLY or B ONLY position the
multivibrator is
held in one
of its
two possible
states by
returning
one grid
to a positive
voltage
and the other grid to a negative
voltage.
For example, in the
A
ONLY
position the grid
of
V3375A is
held
positive and this half of the
multivibrator
conducts while the grid ofV3375B
is held
negative
and this half is cut off. When
V3375A is conducting the cathode is above
ground which causes
V3384B
to conduct
and it
in turn
pulls the grid
of V3393B toward
ground
lowering
the
plate voltage of V4334
and V4354.
This
reduced plate
voltage
cuts off the following
stage
(V4364 and V4374) and the B-channel
amplifier
is held
in a non-conducting state.
The
converse is true
of the A-channel amplifier.
The
grid of V3384A is
near ground potential
with
reduced
plate
current, therefore, the
plate
of
V3384A
and
consequently the grid of V3393A
are permitted to become more positive
thus
providing
plate voltage for V3334 and V3354.
The
A-channel
then
conducts.
ALTERNATE
Turning the
MODE
switch to the ALTERNATE
position
returns
both grids of the multivibrator
to
a
negative potential. It is then a
bistable
multivibrator.
At the
end
of each sweep cycle
a negative-going trigger
is generated and is
coupled to the multivibrator through the Trigger
Coupling
Diode V3382. Each trigger causes
the multivibrator
to " flip" from one stable
state to the other. This
alternately
switches
the amplifiers on
and
off. The switching rate
is now
determined by the repetition rate of
the
sweep.
CHOPPED
Turning the MODE switch to the
CHOPPED
position
returns both grids of the
multivibrator
to
a
positive
voltage and the multivibrator
free
runs at a rate determined by the
time
constant
of the grid circuits.
The two amplifiers
are
alternately cut off and allowed to
conduct
at
the free-running
rate
of the
multivibrator.
ADDED
ALGEBRAICALLY
Turning
the
MODE switch
to the ADDED
ALGEBRAICALLY
position returns
both grids
of
the
multivibrator to a. negative voltage. Both
sides
of the multivibrator (V3375) are held
sufficiently
negative so
that incoming
triggers
have
no effect
on the multivibrator grids.
The
cathodes
of both halves of the multivibrator
follow
the
grids down,
driving V3384A and
V3384B
to cut off. With V3384A and V3384B
cut
off the
plate voltage rises, carrying the
grids of the
following stages, V3393 A and V3393B
with
it.
The
cathodes of V3393A and V3393B
follow
the
grids
up. When the cathodes are
up,
both amplifier channels conduct
equally
in
the
absence of any signal.
Note
Plate
voltage for the input ampli
fier stages of both channels is
supplied
by the
cathodes
of either
V3393A or V3393B.
Under the conditions described above signals
applied to both inputs will be amplified equally
by either channel. Algebraic addition of the
signal
occurs at the grids
of the output
stage,
V4383.
In phase
input signals add, out of
phase input
signals subtract, at the grid of
each
tube
if the
polarity switches
are at the
same setting.
3-2
Circuit
Description
- Type
CA
AA
Содержание TYPE CA
Страница 3: ...Type CA http manoman sqhill com...
Страница 35: ...R4311E TYPE CA A VOLTS CM B BOTTOM VIEW...
