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rectifier
circuit
in the
collector
circuit
of Q8,
and switch S2B
applies bias to the base of Q9 by
connecting it to the collector of Q8.
Since the function selector switch іп the OUT-
PUT
position
disconnects
the
rectifier
meter
circuit,
distortion
due to the rectifier
diodes
is
eliminated.
Thus,
the amplifier output contains
very little distortion,
а.
Output Stage
When the collector of Q8 is connected
to the
base of Q9 through section S2B of the function se-
lector
switch,
ап
output
signal
appears
at
the
emitter
of the N-P-N
transistor
09.
This
signal
is coupled to the output connector
on
the
front
panel through
C31,
a 100
uuf capacitor
and
a
shielded cable.
The output impedance of the amp-
lifier is approximately
50 ohms,
e.
Meter
Circuit
The output of Q8 is applied
to a full
wave
bridge
rectifier consisting of two high frequency
diodes
(СКЗ
and
Ска).
A
0-50
microampere
taut-band meter
movement
(М1)
is
connected
a-
cross the output of the rectifierto
measure
the
re-
sultant
d-c
current.
Signal
current
from
the
meter
circuit is fed back
to the amplifier to ob-
tain gain stability and meter
linearity
over
the
entire bandwidth.
fe
Power
Supply (S1053C Only)
The
Model
S1053C
AC
Voltmeter
may
be
powered
from
either an internal battery or from
the rectifier circuit which operates
from the a-c
line.
The
rectifier
power
supply
consists
of
transformer ТІ and diode rectifier CR5.
Filtering
is accomplished
by means
of the filter network
circuit C32,C33
and R55.
Zener diode CR6 pro-
vides
voltage
regulation.
Transformer
Tl
is
built
into
the
large cylindrical plug РІ which is
plugged into the a~c line; a cable from РІ carries
low voltage secondary current
and
is
terminated
at the other end by P2 which plugs into J1 on the
case
of the instrument.
6.
OPERATION
a.
Mechanical
Meter
Zero
A
screwdriver
adjustment
is used to mech-
anically
zero
the
meter.
It is located
on
the
meter cover.
If the meter pointer does not rest
directly in line withthe Oline of the voltage
scales
when
the
power
switch
is in the
OFF position
(instrument uprighton feet),
turn this adjustment
left or
right
until the pointer is directly in line
with the 0 line.
b.
Operation from an AC Source (Model S1053C)
(1)
Connect the female plug end of the power
cable
to the
receptacle
at the rear of the instru-
ment
case.
(2)
Connect
the male
plug end of the power
cable
to a 117 v a-c
(50-400 cps)
receptacle.
A
230 v a-c
power
source
may be reduced to the
required
117 v a-c with the Model SKN60094A 230/
117 VAC
Adapter
Cable Kit.
(3)
Placethe LINE side ofthe function switch
in the B+ CHK. position and check the power
sup-
ply output by observing the reading on the LINE
OR BATTERY
O.K.
scale.
(4).
Rotate
the
LINE
side
of
the
function
switch to the METER
position for voltage mea-
surements
or to the OUTPUT
position for amp-
lifier applications.
|
МОТЕ
Should sensitive measurements
require
complete
isolation
from
r-f
energy
which
may be present on the a-c line,
switch
the
Model
S1053C
to
battery
operation and remove
the
power
cable
from the instrument
housing.
с.
Operation From
Internal Battery
Place the function switch in the B+ СНК,
po-
sition,
A new battery will give ameter
indication
near the upper limits of the LINE OR BATTERY
О.К,
scale.
After a few hours
of operation,
the
meter indication will be approximately
mid-scale.
If the meter indication just reaches
or falls below
the lower limits of the scale,
the accuracy
of the
instrument
will
be affected and the battery must
be replaced,
Refer to the MAINTENANCE
para-
graph of this manual for detailed replacement in-
formation.
d.
AC Voltage Measurement
(1)
Place
the
function switch in the ON po-
sition.
(2)
A rapid check of the condition of the in-
strument may be performed by placing the range
selector
switch
in the
1 MILLIVOLT
position.
The
meter
indication
should
be
anywhere
from
0.1
to fullor off-scale deflection depending on
the proximity of stray
electric
fields from
a-c
power
lines.
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