I.C.E Supertester 680 R - DC Current Measurements

As
it may be
seen Jrom
the electrical
diagram relating
to alternating
current voltage measure-
ments,
our
SUPERTESTER Model
680
R,
as
well
as
almost all the most
populai
Anrerican
analysers,
has adopted.a
rectifier
circuit with
only one half wave
becausd
ihis
system, in
add.ition
to measuring
the normal
alternating current,
makes it
possible
to
check the
iymmetry
of the
arerage value betYveen
the two
aliernations
of tho alternating
current
being eiarnined.
ln fact in
practice.it
may happen
that
tw'o half waves
of
an alternating current
may become
asymnletrical,
i.e. that the
two half waves
have not
the same
outline anrl
the same
dmplitude.
An
exairple would
be the
presence
of a direct component.
Slrould
-this
asymmetry affect
the average
value, it may
be revealed
by the
l.C.E. Tester
lJlod.
680
R
by reversing
the Ieads
at
the measuring
p0ints.
The cliffdrence
betvreen
the
two measurements makes
it
possible
to
calculate the
average value,
the
percentage
of
asymmetry
present
and therefore
the
v1-v2
%
of asYmmetrY
-
---
i00
V1
where V1
:
maior
dcviation
V2
=
minor
deviation.
CURRENT MEASUREMENT
WIT}I O.C.
(mA)
WARNINE:
F0r
current measurements,
the
instrument must
always
be connected
in series
with the circuit
(see
figure
page
17).
Never
cornect
the
instrument
in
parallel
with the
circuit
live like with
the measurements
of
voltage
(Volts),
because
the
resistances and
shunts would
get
damaged,
especially
those wiih
a
loyr
ohm
value.
Make
sure that with current
measurements
(mA
D.c.)
the black
lead
(negative)
is inserted
as faI.as it.will
g0
into thc lower
ceniral
socket marked
with the
black wordin!
on a white
ground
"="
(D.C.)
and the other
red one
(positive)
in
one
marked
,'50
uA
-
500;A
-
5 mA
-
50 mA
-
500 mA
-
5
Amp"
according
to the range
required.
It is most i.mportant
to.bear in
mind that,
when there
is doubt
about the amplitude
of the
current to be measured,
the highest
range
(5
A.)
should always be
used
s6 at to
avoid
damaging the resistances
and shunts in the
circuit.
14
subsequenfly,
if required, after
the first
reading,
the red
lead of the
various
ranges
may be
insertrjd int'o'
the n6xt
lowest
range so as
t0 obtain
a more
accurate
reading.
ioi tf,e ranges
100
pA, 1
mA, 10 mA,
100
mA, 1
A.and.10
A D-C., use
the
sockets.of
the
,ine.i 5o
"1,
sOO
uA,
S, 50,
500 mA and
5
A,
pressing
the sensitivity
buttcn
wh.ictt.
doubles
ttre"ianees-in
consiheratl6n,
To
make anyway
this
point
clearer,
the.following
table
to
be
taien
in-to accgunt
for
a more
accurate
ieading
of
the scale,
referring to
the range
and
theref0re
to the selected
sockets.
Sel ected
range
Sockets
to
be used
Se
nsiiivity
key
AVx
2
N
u
mbering
to be
read
on the scale
Multiply
the
read-
ing
by
Divide
the
read-
ing by
50
pA-
100
pA=
500
pA:
1 mA=
50
mA=
10 mA=
50
mA=
100 mA=
500
mA=
1A:
5A=
10
A=
and
50
pA-
and
500
y,A=
and
5
mA:
and
50
mA:
and
500
mA=
and
5
A=
,-)
(:)
(=)
(=)
(:)
RELEASE
DEPRESS
RELEASE
DEPRESS
RT.LEASE
DEPRESS
RTLEASE
DEPRESS
RII-EASE
DEPRESS
RELEASE
I}TPRESS
from
0 to
50
from
0 to
10
from
0 to 50
from 0 to
10
from 0 to 50
from
0 to
10
from
0 to 50
from
0 to
10
from 0 to 50
from
0
to 10
frcm
0 to 50
frnm 0 to 10
x10
1l'
,10
t'
:10
,I
10
10
15