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341
343A
REF. NO.
NAME
FUNCTION
6
CURRENT
LIMIT
control
Sets operating
point
of controlled current
limiter,
which
limits
max-
imum
output
current to
any
value
from
zero to
about 25
milliamps.
7
Ground
Terminal
Connection
for
grounding
either positive or negative
OUTPUT
term-
inal
to
power
line
ground.
8
OUTPUT
terminals
Output
voltage
connections,
.with
both
terminal
isolated
from
instru-
ment
case
and
power
line
ground. Terminals
may
be
floated
up
to
500
volts
dc
from
chassis.
9
SENSE
terminals
Direct
connection
to
instrument
regulating
circuitry.
Connected
to
OUTPUT
terminals or
remote
load to provide
optimum
load
regu-
lation.
10
Decimal lamps
Indicate location of
decimal point
for voltage
dial
readout,
and
are
controlled
by
the
RANGE
switch.
11
Voltage
dials
Six voltage
dials
(seven
dials
on
the
343A)
set
output
voltage
and
pro-
vide
in-line digital
readout
from 0
to
1 1
1
1.110
volts
dc
(0 to
1
11
1.
1 1
10
volts
dc
for
the
Model 343A).
A
dial set
to
"X"
(10) repre-
sents
0
with
a
carry of
1
to
the
left,
thus
1
1.1
1
110 would
be
dialed
as
10.XXXXX.
NOTE:
In dial
readout
notation,
the underscore
(10)
denotes
a single
dial
that
is
displaying
two
significant
digits.
12
Meter
Indicates
OUTPUT
voltage or load current,
depending
on
setting
of
FUNCTION
switch.
The
meter
voltage range
corresponds
to the
setting
of the
RANGE
switch.
Voltage
is
indicated
on
a
0
to
10
scale,
with
10%
over-ranging.
The
meter
current
range
is
fixed
at
0
to
30
milliamps.
NOTE:
Meter
current
includes beta
string current.
This introduces
a
small
error,
which
is
negligible
on
the
10 and
100
volt ranges;
in
the
1000
volt range,
the
error
will
be
equal
to
+
1
milliamp.
13
Terminal
strip
Provides
output,
sense,
and ground connections
for
rack-mount
in-
stallations.
Standard
on
the
Model
343A
and option only
on
the
Model 341
A.
14
Fuse, high voltage
High
voltage
power
supply output
fuse, rated at
1/16
amp,
slow blow.
15
Fuse,
line
Power
line
fuse,
1
amp
slow
blow
for
115
volts ac
operation
and
1
/2
amp
slow
blow
for
230
volts
ac operation.
Figure
2-1.
CONTROLS, TERMINALS
AND
INDICATORS
(Sheet
2 of
2)
No. 28
wires,
each
3
ft
long, are
used
to
connect
a
load,
requiring
25
milliamps
to the
OUTPUT
terminals of the
Model
341
A/343
A.
With
a
straight
edge,
connect
the
known
current
on
scale
1
(25
ma)
and
the
wire
size
on
scale
2
(No.
28).
The
resulting
IR
drop
on
Scale
3
is
approximately
1.65
millivolts
per
foot.
Therefore, the
connecting
wires
develop
a
total
voltage of
12
millivolts
(2 x
3ft
x
1.65
mv/ft
=
9.9
mv), which
is
more
than
one
and
one-half times the published load
regulation
of
the
instrument
at
1000
volts
output.
To
compensate
for
this.
2-3
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