HP AC-4A - AC-4 A Driving Circuit and Triggering

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C.
DRIVING
CIRCUIT
FOR
AC-4A
Triggering
of
the
Amplitude
Discriminator
is
at
the
approximate
de
levels
shown
below
when
connected
as
in
Fig.
2.
PLATE
Pin
I
V2
(Fig.
3)
is
normally
conducting
for
O
v
de
on
Pin
5
(INPUT)
of
the
522B
-58B
Amplitude
Dis
-
criminator.
PLATE
Pin
1
of
VZ
cuts
off
when
the
de
level
at
the
INPUT
crosses
approx.
-0.
4
volt
going
negative.
PLATE
Pin
1
of
VZ
conducts
again
when
the
de
level
at
the
INPUT
crosses
approx.
-0.
2
volts
going
positive
from
a
negative
peak.
An
AC
-4A
driven
from
this
Amplitude
Discriminator
will
count
at
"A"
if
driving
from
Pin
3,
at
"B"
if
driven
from
Pin
1
of
the
Amplitude
Discriminator.
Positive
de
levels
at
the
INPUT
(Pin
5)
WILL
NOT
trigger
this
discriminator.
An
attenuator
and
a
de
buck
out
voltage
can
be
used
in
the
input
circuit
of
the
Amplitude
Discriminator
if
it
is
desired
to
trigger
the
counter
at
some
particular
place
on
an
input
wave.
0
VI
I-
...J
0
- .2
>
0
0
-.4
Fig.
4.
Trigger
Levels
of
the
522B
-58B
Amplitude
Discriminator
Connected
as
in
Fig.
1
-6-