Farnell L30A - Page 10

(tV)
Mains
Supply
Change
Short
term mains
variations of up to
10%
give
corresponding
variations
of up
to
0.01%
on the
output.
Surges
on
the
mains
supply
in the
form of
short
rise
time pulses
can be fed
on to
the
mtput by
stray capacity.
Where these
conditions exist
a
capacitor
suppressor
filter
should
be connected
in the
mains
lead.
(c)
Component
Temperature
Change
Output
variation is caused
by
component
value
changes due
to temperature
change.
The
temperature
change
can be
(I)
as
a result
of ambient
change, or (II)
as a result
of
unit
internal
temperature
change,
caused by
changing internal
dissipation
from
a
change
in load
or supply to
the
unit.
(I)
Ambient
Change—The
typical
temperature
co-efficient
of
output
voltage
is
.02%
per
degree centigrade
of
ambient
change
(II) Internal
Change—Fig.
(5)
shows
typical
output
variations
caused
by
mains change
and load change
plotted
against
time.
CONSTANT
VOLTS
Link
to "CV"
Four
Terminal Units
-f/s
-o/p E +Q/P +F/B
Q Q O
Q
Q
CONSTANT
CURRENT
Link
to
"CI"
-f/b -a/r
L-j
LOAD
I
e +cyp +f/h
O
Q
Q
LLjvv^
Three Terminal
Unfit
-O/p 1
I
Const
j—
o
o—
1
+
LOAD
1
Const
ro/p
1
I
j-2
$-
LOAD
Rs
Fig.
I. CV and
CI Goftnectio
Ifi-T
J
z
<
a
r 0.5S!
. .
S
0.II1--
00
K 100 K
IN 1M
12
FREQUENCY
Mi
Fif.
2.
Output Impedance
13