I.C.E Supertester 680 R - DC Resistance Measurements (1 Ohm to 10 Megohms)

MEASUREMENTS
OF RESISTANCE
IN DIRECT
CUNRENT
(from
1 ohm
to 10 megohms)
(trom
7/!0
ohm
to 30
ohms
see
page
23).
Before
effecting
any measurement
of
resistance
in
a circuit
make
sure that
the
circuit
is
n-ot live,
because
if the
ohmic
circuit
of the
tester is
live
the
tuse
proteciion
Ourni
ir'ut
anO
if the
existing
voltage
is lower
than 140
volts the
relative
resistancds
iie
oamigeu.'uaving
crecked
this
p0int,
f0r low
medium
and high
resistance
measuremenis,
introcucl--is
tar
as
it
will
go
one
of the teads
into
the tcwer
iccket marked
in
btack
fZ
dnO lfie"oifrei-feaO
in
one..ot
the,upper
sockets
marked
also in
black
exl
-
Ox10
-
d-x100
and
ei1OOO
r._
cording
to the range
required.
The
next step
is to
c0nnect
the
plugs
together
and
turn the
knob marked,,REG.,'(battery
adjustnrent)
until
the
instrument
priinter
is at the
full
scale value,
i.e.
it
;0,,
on-ms.
'iiniil!
connect
the resistance
to be..measured
acrcss.ilre
two
plugs
making
iure
tnat itie
reaaing
taken
on the upler
scale of the
instrument
relating
to ihe-ohms
vaiue is
muttipiieo
uy
tt6
range chosen.
Every
.time
the
range
of the ohmetei
is changed,
repeat
thi zeioi'ne-ooeiation
by turning
the
ceniral knob.
when
it
is no longer
possibte
t0'gei
trre
pointei
id
iriturn
to
zero, change
the battery
incorporated
(an
ordinary
3 Volt
batt"ery useu
toi-
trino
lcrctresl
making
sure that
the
polarity
is corrcct.
i.ange. ln
the range
0hms x
1, the following
will be
the relation
between the
scale
in chms
,
and the corresponding
flow in
mA.
0
0.595 2$6
6.75
1?25 20.6
2r,
28f
35.3
r.62
5(.5 66.6
20&0
60
80
For tle battery
replacement,.
see the
chapter
dealing
with mainienance
(page
3g). Having
completed
the resistance
tests,
never leave
the
terminals
in
position
on"th"J
ohmlc
circuit
because
.the
plugs
might
be
shortened
and discharge
the battery
iriei
i
wtiie.
"
iriitr.r*ore
me 0nmrc
clrcult lnc0rporat€d
might
accidentaliy
be
connected
to
a
live
circuit
and
thus
d.amage,.as
above mentioned,
the
fuse
prctecti0n.
ln
this case
to
restore
the
fuse follow
the detailed
instructions,
page
39.
It.may
be.us-eful
for
the
operators
of the
Supertester
6g0R to
know
the
various
current
values
'r/nich
tlow according
to the
ohms
value 0f the
resistance
being
tested
and the
selected
20
For
the ohms
x
10 range, divide
the readings
by
10.
F'or the ohms
x
100 range,
divide the
readings
by 100.
Fcr the
ohnrs
x 1000 range,
divide
the readings
by
1000.
li should be b0rne
in
mind that
the various
readings
mentioned above
will
be obtained
Drovided
the 0hms
circuit
is fed
with exactly
3 volts. Should
the
battery
provide
a
greater
br
a
lesser voltage,
the readings
will be effected accordingly.
These output
figures are
useful
and important
for various
applications such
as, for.
example,
the measLiring
df
the consumpti0n
0f an
instrument
or a
relay, 0r
t0 know on
which
range
to measure
tEe continuity
0f
ihe filament
of a valve
or
a
low voltage
lamp sc aS
t0 ensure
that such a
filament
is
not overloaded
and thus
fused'
ln measuring
bear in mind
that the
common
ohms socket
is
positive
while that
of.the
various
rangei, ohmixl,
ohmsx10,
ohmsx100
and
ohmsx1000
is.negative.
This
point
is
important
espec;aily
when
measuring
rectifiers
and electr0lytic
capacitors.
21
-
negaiive;
+
poslttve.
)
10