probe.
The
reading
wirl
be
1050
trl
approximately..
In
this
case,
the reversing
of the
probes
causes
a considerablv
lower
reading
as the
diodi
in
parallel
relitivd
to'inu
ies-istoi"are
set
in direct
conduction.-
To
meas-ure
t[e
220
o-ieiltoi
iei trre
reference
Test
Meter
on
ox
10,
insert
the
red
probe
in
the
2
.v
R.c.
societ
ano,
witrr-
tt ,i
biiiii
p,.i,1.,-iJl,.n
'tni'
ioint
z
(see
diagram),
the
reading
wiil
be
720
O
appr.xiinatilV.'
PARASRAPH
1())
A)
output
nieasurement
check:
the
above-mentioned
circuit
follows
the
sequence
0f the
Volts
circuit
in
A.c.,
the
onrv
exrra
erement
is
tne
capaiitoi
which
can de;r];;k;j
ni
jo}o,ring
the instructions
rerative
to
frequency
measuremenis.
A
fa;ii'ir"iti;
l"upilit#?rrl'noii,
to
,
short
circuit
or
a disconnected.
coniponent
lead,
makes
ttre
reaoing
;f ti,r;-
mi;-,
-ti.qr.n.y
impossibl.e-.
The.reading
would
be
itre
ena Jt'sciie-1oi
a
sh0rtcircuit
and
it would
rnove
0nly
slightly
in
the
event
0f
a disconrecteo-componeni-ieau.-
lt requiiei,'lt'ts'poss-inte
to
carry
out
a static
check
of
the
capacitor
as follows,
lnsert
the
reference
Test
Meter
on
ox
1oo,
insert
the
red
probe
in
the
0UTpur
socket,
and
the
black
probe
in
ihe 250
uA
societ.
wiit a rew morirant. anrr rhpn rovarco +h6 hr^h^.
the
black
probe
in
ihe 250
pA
rne
,racK
proDe
rn tne
z5u
u,A
s'cket.
wait
a
few moments,
and
then
reverse
the
prbbes.
A
slight
impulse
of
amplitudb
of half
a
division.
shouiJ occrrr Thic tpcr
^^nrirmc
,,harh6r
the capacitor
is
working
correcfly
or not.
a
division,
should
occur.
This
test
confirms
whether
50
I ISl
OF P()SSIBI.E
FAULTS
DUE
Tl) ALIERAIIONS
()R
I$IIERRUPTII)N
II'I TIIE
VAIlI()US C()MP()NENTS
Ilrr: {ollowing is a
list of
the various
comp0nents
with an
indication
of faults
shown
up
by
tlrr:rI if their values
go
infinite
(interrupfion)
or drop
to zero
(short
circuit);.0bviously
a
:rrrrglle increase
or decJeaSe
in
the determined
value
indicates
a fault
which is
less
grave
lrul
which shows
the same
symptoms
as
extreme
cases.
I^ULTY
OR
ATTERED VAIUE,
720
O
ll
irrterrupted the
needle ioes
noi move,
energising
the
ranges. 100
mV' 50-
p,A, 2 V A'C',
:"rt)
1r,A
A.C. lf shortcircuited
the
reading exceeds
50%
for
the
i00 mV D.C.
range, and
lr':1,
ior the
2 V A.C.
range.
There is n6
reading
error f0r
the 50
p,A D.C. and
250
p,A
A {).
ranges.
lAU|-TY VATUE
2720
A
It interrupted, the
needle
does not
move supplying
the
V ranges-D:9.-flom
2 V to
1000
V
t,,,,i,1rire.'li'shortcircuited
the
reading exc'e'eds
7.5% on
the
2 V DC.
range and
l'51"
,rt)t)rox.
for the
10 V, range,
and so
on in
proportion
f0r the
other
ranges'
I
'\ULTY
VATUE 36 KO
rr inierrupied, the
i-eedle
d6es not
move supplying
the
V ranges
D.C. from
2 V
upwards
llr)
same applies
t0 the
ranges
in A.C. from
10 V
upwards.
It
r;trortcircuiied on
the rang;
2 V
D.C. the reading
is excessively
high
(tne
needle.goes
to
,',,,i
oi iriie with
240
mV-approx).
0n
the 10
V D.C.
range
the.reading
exceeds
207o
ir|t)rox.,0n the 50
V D.C.
range, the
reading
exceeds
4% approximately,
and so
0n
In
prrrportion
for the
other
ranges.
irrr'the
A.C. range
there
is alery
large error
in excess
which
iS
reduced for
the
l0wer
ranges.
IAULTY VAIUE 160 l(O
ll
interrupted the
Test Meter
works
normally
up to
the
2 V D.C., and
10 V
A'C' ranges
rr,
Irrsive,
no
indicati0n
in the
upper ranges.
lt
:;lrorl6ircuited,
the
Test Metei
works
normally
up to
the 2 V
D.C.,
and 10
V A.C.
ranges'
51
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