HP Lab Series User Manual

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b.
Set
METER
switch
to
highest
voltage
range
and
turn
on
supply.
c.
Adjust
VOLTAGE
control
until
front panel
meter
reads
2
0
Volts.
d.
Set
AMPLITUDE
control
on
Oscillator
to
10
Volts
(Ein},
and
FREQUENCY
control
to
lOOHz.
e.
Record
voltage
across
output
terminals
of
the
power
supply
(E
0
)
as
indicated
on
ac
voltmeter.
f.
Calculate
the
output
impedance
by
the
following formula:
Zout
=
EoR/
CEin
- Eo).
Eo
=
rms
voltage
across
power
supply
output
terminals.
R
=
1000
Ein
=
10
Volts.
g.
The
output
impedance
CZout)
should
be
less
than
0.020
ohms.
h.
Using
formula
of
Step
(f),
calculate
out-
put
impedance
at
frequencies
of
SOKHz
and
SOOKHz.
Values
should
be
less
than
0.5
ohm
and
3.0
ohms,
respectively.
5-34
Temperature
Coefficient.
Definition:
The
change
in
output
voltage
per
degree
centigrade
change
in
the
am-
bient
temperature
under
conditions
of
constant
input
ac
line
voltage,
output
voltage
setting,
and
load
resistance.
5-35
The
temperature
coefficient
of a power supply
is
measured
by
placing
the
power
supply
in
an oven
and
varying
it
over
any
temperatUre
span
within
its
rating.
(Most
t
pewer
supplies
are
rated
for
oper-
ation
from
o
0
c
to
5s
0
c.)
The power
supply
must
be
allowed
to
thermally
stabilize
for a
sufficient
peri-
od
of
time
at
each
temperature
of measurement.
5-3
6 The
temperature
coefficient
specified
is
the
maximum
temperature-dependent
output
voltage
change which
will
result
over
any
soc
interval.
The
differential
voltmeter
or
digital
voltmeter
used
to
measure
the
output
voltage
change
of
the
supply
should
be
placed
outside
the
oven
and
should have
a long term
stability
adequate
to
insure
that
its
drift
will not
affect
the
overall
measurement
accu-
racy.
5-3
7
To
check
the
temperature
coefficient,
pro-
ceed
as
follows:
a.
Connect
test
setup
shown
in
Figure
S-3.
b.
Turn
CURRENT
controls
fully
clockwise
and
adjust
front
panel
VOLTAGE
controls
until
the
front
panel
voltmeter
indicates
maximum
rated
out-
put
voltage.
c.
Insert
the
power
supply
into
the
tempera-
ture-controlled
oven
(differential
voltmeter
and
load
resistance
remain
outside
oven).
Set
the
tempera-
ture
to
3o
0
c
and
allow
30
minutes warm-up.
d. Record
differential
voltmeter
indication.
e.
Raise
the
temperature
to
40°c
and
allow
30
minutes
warm-up,
f. The
differential
voltmeter
indication
should
change
by
less
than
330mV
(660mV
for
Model
6209B)
from
indication
recorded
in
Step
(d).
5-7
5-38 Output
Stability.
Definition: The
change
in
output
voltage
for
the
first
eight
hours
following
a
3
0
minute
wann-up
period.
During
the
inter-
val
of
measurement
all
parameters,
such
as
load
resistance,
ambient
temperature,
and
input
line
voltage
are
held
constant.
5-39 This
measurement
is
made
by
monitoring
the
output
of
the
power
supply
on
a
differential
volt-
meter or
digital
voltmeter
over
the
stated
measure-
ment
interval:
a
strip
chart
recorder
can
be
used
to
provide a
permanent
record.
A
thermometer
should
be
placed
near
the
supply
to
verify
that
the
ambient
temperature remains
constant
during
the
period
of
measurement. The
supply
should
be
put
in
a
loca-
tion immune from
stray
air
currents
(open doors
or
windows,
air
conditioning
vents):
if
possible,
the
supply should
be
placed
in
an
oven
which
is
held
at
a
constant
temperature.
Care
must
be
taken
that
the
measuring
instrument
has
a
stability
over
the
eight
hour
interval
which
is
at
least
an
order of
magnitude
better
than
the
stability
specification
of
the
power
supply
being
measured.
Typically, a
sup-
ply
may
drift
less
over
the
eight
hour
measurement
interval
than
during
the
4
hour
warm-up
period.
5-40
Stability
measurement
can
be
made
while
the
supply
is
remotely
programmed
with
a
fixed
wire-
wound
resistor,
thus
avoiding
accidental
changes
in
the
front
panel
setting
due
to
mechanical
vibra-
tion
or
"knob-twiddling".
5-~l
To
check
the
output
stability,
proceed
as
follows:
a.
Connect
test
setup
shown
in
Figure
5-3.
b.
Turn
CURRENT
controls
fully
clockwise
and
ad}ust
VOLTAGE
controls
for
160Vdc
output
(320Vdc
for Model
6209B).
c.
Allow
30
minutes
warm-up
then
record
the
differential voltmeter
indication.
d.
After
8
hours.
differential
voltmeter
should
change by
less
than
165mV
(32SmV
for
Model
6209B}
from
indication
recorded
in
Step
(c).
5-42
CONSTANT
.CURRENT
TESTS
5-43
For
output
current
measurements,
the
current
sampling
resistor
must
be
treated
as
a four
terminal
device.
In
the
manner
of
a meter
shunt,
the
load
current
is
fed
to
the
extremes
of
the
wire
leading
to
the
resistor
while
the
sampling
terminals
are
located
as
close
as
possible
to
the
resistance
portion
itself
(see
Figure
5-9).
Generally,
any
current
sampling
resistor
should
be
of
the
low
noise,
low
temperature
coefficient
(less
than
30ppm/OC)
type
and
should
be
used
at
no more
than
5%
of
its
rated
power
so
that
its
temperature
rise
will
be
minimized.
The
latter,
reduces
resistance
changes
due
to
thermal
fluctuations .

HP Lab Series Specifications

General

Brand	HP
Model	Lab Series
Category	Power Supply
Language	English