AVO AVOMETER 8 User manual
OPERATING
-
INSTRUCTIONS
AVOMETER
MODEL
8
Mark
5
..
CONTENTS
SPECIFICATION
Table
of
Ranges
Accuracy
e
tc.
ACC
ESSORIES
Re
pl
aceme
nt
Batt
e
ri
es
OPERATION
General
Curr
e
nt
Meas
urement
Voltag
e
Measurement
R
esistance
Measurement
In
s
ul
at
ion
Resi
sta
nc
e
Measurement
De
cib
el
Measurement
Pol
arity
R
eve
rsal
Control
Overload
Protection
E.H.T.
Measurement
TRADE
MARKS
• 1
1
2
2
3
3
3
4
6
6
6
6
8
Tho
Trodo
Marks AVO and
AVOM
E'TER
aro
the
ex·
·
elusive property of Avo Limited.
Heavy
A.C.
Current
Measurement
Heavy
D.C.
Current
Measurement
Non-
S
in
e
Waveforms
DESIGN FEATURES
Design
and
Construction
Ra
ng
e
Controls
The
Movement
Scaling
SERVICING
YOUR
·
AVOME
TER
Replacement
of
Batteries
and
F
us
e
Plug-in
type
leads
AVO
Repa
ir
s
Dep
ar
tment
Ta
bl
e
of
Components
Circuit
Diagram
SWITCH
TRANSIT
POSITION
9
9
9
10
10
10
10
11
11
11
12
13
During transit the /e
ft-hand
switch
should. be set to
OFF.
The
ri
ght-hand switch should be set
to
D.C.
SPECIFICATION
TABLE
OF
RANGES
DC
Voltage
3000V .
1000V
600V
300V
100V
30V
10V
3V
10omv•
DC
Curront
10A
1A
100mA
10mA
1mA
300~tA
50~tA
•on
the
50!LA
range
Resistance
AC
Voltage
3000V
1000V
600V
300V
100V
30V
10V
3V
AC
Current
10A
1A
100mA
10mA
0
to
20000
(200
centre
sca
l
e)
0
to
200k0
(2kn
centre scale)
0
to
20MO
(200k0
centre scale)
0
to
200MO (2MO centre scale)
}all
self-contained
with
external voltage
ACCURACY
D.C. Voltage & Current
Ranges
A.C. Voltage & Current
Ranges
(50Hz)
SENSITIVITY
20,0000/V
±
1%
of
f.s.d.
±
2%
of
f.s.d.
D.C. Voltage Ranges
A.C. Voltage Ranges
2,0000/V
(above 1
OV)
FREQUENCY
RESPONSE
Variation from reading at 50Hz, on A.C. voltage ranges
up
to
300V and A.C. current ranges is not greater than
±
3%,
between 15Hz and 15kHz
•
TEMPERATURE
RANGE
Operation: - 5°C
to
+35°C
Storage: -
40
°C
to
+50°C
TEMPERATURE
EFFECT
Variation due
to
temperature change, not greater than
0·15% per degree C
FLASH
TEST
.•
7kV proof
OVERLOAD
PROTECTION
High speed electro-mechanical cut-out
with
a fuse on
the
two
lower resistance ranges
RESPONSE
TIME
Typically 1 second
to
full
sca
le
ACCESSORIES
TEST
LEADS
1 metre (approx. 42in.)
with
4mm plug
end*
1.8 metres (approx. 72in.)
with
hook
end
3 metres (approx. 120in.)
with hook end
TEST
PRODS
Long reach safety clips
(red and black)"'
Standard
AVO
prods
(red and black)
TEST
CLIPS
Bulldog clip*
Insulated clips
CARRYING
CASES
Standard leather
case
Ever-ready leather
case
CURRENT
SHUNTS
100
Amp 100mV
30
amp}
300
.Amp
AVO
8 mk5 only
600 Amp
2
AVO
part Numbers
Pt.
No. 6220-003/4 (pair)
Pt.
No.
209130/0
/R (pair)
Pt. No.
20913L/M
(pair)
Pt.
No
. 6220-007 (pair)
Pt.
No
. 6220-008 {black)
Pt.
No
. 6220-009 (red)
Pt.
No.
6120-012/3
(pair)
Pt.
No. 6120-003 (each)
Pt.
No. 14319
C/
D (pair)
Pt.
No
. 6320-002
Pt.
No
. 6320-052
Pt.
No. 6220-01 5
Pt. No. 6220-016
Pt. No. 6220-017
Pt. No. 6220-018
CURRENT
TRANSFORMER
AVO
Multirange transformer
for
a.c.
currents up to
600A Pt. No. 45869
VOLTAGE
MULTIPLIERS
10/30
kV d.c. box type
Pt.
No. 6310-094
30 kV d.c. probe type
Pt.
No. 6220-039
REPLACEMENT
BATTERIES
Ever
Ready
SP2
(or equivalents, Pt. No.
25511-013
Burgess
21
0 or 230,
Ever
Ready H
P2,
IEC R20, LeclancM
R20S,
Ray-0-
Vac
13
or
3D, Varta 232)
AND
Ever
Ready
B121
(or equivalents.
Pt.
No. 25511
-181
Burgess
U1
0,
IEC
1
OF20,
L
ec
lanche 215G,
Ray
-0-
Vac
208,
Var
ta 71)
OR
Ever
Ready B154 (or equivalents,
Burgess Y10, IEC 10F15,
Leclanche GB15, Ray-0-Vac 220.
Varta 74)
REPLACEMENT
FUSE
1
~
inch Cartridge
Fuse-
1
A*
Pt. No. 6120-299 (Pack
of
5)
*These accessories
are
included with each
new
AVOMETER 8
OPERATION
GENERAL
The meter is intended for
use
horizontally.
If
the pointer
is not on zero,
it
may
be
set by using the screw head on
the panel.
The leads fitted with Long
Reach
Safety Clips Mark 2
or
clips,
as
required, should be connected to the lower pair
of
meter terminals except when measuring voltages over
1
OOOV
. Long Reach Safety Clips are
not
suitable for high
current.
When measuring current
or
voltage, ensure that
the
instru-
ment is set to either ac or
de
as
appropriate and asuitable
range before connecting up to the circuit under test. When
in doubt, always switch to the highest range and work
downwards, there is
no
necessity
to
disconnect the leads
as
the
switch position is changed.
Do not switch o
ff
by rotating
ei
th
er
of
the knobs to a
blank position.
The instrument is fl
ash
tested at 7000V ac but
if
used
with
accessories on circuits in excess
of
3000V,
it
should be
kept at the
low
potential end
of
the circuit {near earth
potential) or other suitable safeguards must be applied. .
CURRENT
MEASUREMENT
To measure current, the instrument should
be
set to a
suitable ac or de range and then connected in series
with
the
circuit under test.
The voltage drop
at
the meter terminals is 400mV on the
1
OA
de range dropping to 1
OOmV
on the 50 microamp
range. In the
case
of
ac ranges it is
less
than 450mV.
on all ranges. Standard meter leads have a resistance
of
0.02 ohm per pair. Ensure th
at
the circu
it
is 'dead' before
breaking into
it
to make current measurements.
VOLTAGE
MEASUREMENT
When measuring voltage,
it
is necessary to set the appro-
priate range of 'ac' or 'de' and connect the leads across the
source of voltage to be
me
as
ured.
If
the voltage is
un-
known, set
the
instrum
en
t to its highest range, connect
up
and
if
below 1
OOOV,
decrease the ranges step by step
until the most suitable range
has
been
selected.
If
the
voltage should exceed 1
OOOV,
the instrument should be
set to measure
1000\/
as
described above, but the positive
lead should
be
transfe
rr
ed
to the
ap
propr
ia
te 3000V
terminal.
Great care must
be
exercised when making connections
to alive circuitand the procedure should be entirelyavoided
if
possible.
3
OPERATION
When measuring high ac and de voltages (sayabove
SOOV)
unless the common negative terminal is either earthy
or
connected to earth, errors
will
be introduced if the instru-
ment is touched during a reading.
On
de ranges, the meter consumes only 50 microamps at
full scale deflection corresponding
to
20,0000/V. In the
case
of
ac
ranges above 1
OV,
full scale deflection is ob-
tained
with
a consumption
of
0.5mA
(20000/V).
The
1
OV
range is 1
0000/V.
The 3V
ac
range consumes 1
OmA
at
full scale deflection. The meter maintains a high degree
of
accuracy for audio frequency tests
up
to
15kHz on
ranges up to 300V
ac.
All current consuming voltmeters,
however sensitive, draw current to varying degrees from
the circuit under test, thus causing the voltage to fall at
the point
of
measurement.
Owing to the high sensitivity
of
the Model 8 on de ranges.
this effect is unlikely
to
be
of
importance except in a very
few
instances.
It
might effect the measurement
of
e.h.t.
voltage on a television set or the tapping on a potential
divider, where the resistances
are
comparable with the
resistance
of
the meter on the range in
use.
It
is generally
possible to
use
a meter on a higher range than absolutely
necessary where the higher meter resistance causes less
disturbance.
At
the
same
time adequate pointer deflection
for reasonable accuracy should
be
attained.
4
When
it
is essential
to
obtain
an
accurate indication
of
the
voltage developed across a high value resistor
it
is some-
times preferable
to
insert the meter in series
with
it
and
to
measure the current flowing. The reading in milliamps,
multiplied by the value
of
the resistance in thousands
of
ohms,
will
give the developed voltage.
RESISTANCE
MEASUREMENT
There
are
three self-contained ranges covering from 1 ohm
to 20 megohms and provision is made for upward ex-
tension
of
these limits.
On resistance ranges, the meter must
have,
in addition
to
the normal instrument zero a resistance zero corresponding
to
the full scale deflection
of
the meter. Before carrying
out
tests for resistance, a check should be carried
out
to
ensure that the meter actually indicates zero ohms irres-
pective
of
the condition
of
the battery (within the limits
of adjustment described later).
The accuracy, should
be
within
3%
of
the reading about
centre scale. increasing
up
to about 10%
of
the indication
around deflections corresponding
to
10% and
90%
of
full scale deflection.
Resistance tests should neverbe carried
out
on components
which are already carrying current.
•
OPERATION
On three ranges which utilisethe internal source
of
voltage,
a positive potential appears at the negative terminal
of
the instrument when set for
res
istance tests. The resistance
of
some components
var
i
es
according to the direction of
the current through them
and
readings therefore, depend
upon the direction in which the test voltage is applied
quite apart from its magnitude. Such
cases
include elec-
trolytic capacitors and rectifiers.
When measuring the leakage resistance of
an
electrolytic
capacitor, the negative lead from the meter s
ho
uld be con-
nectedto thepositive terminal
of
the capacitor and theohms
x 1
Ok
range employed.
Before making resistance tests the pointer should
be
adjusted to zero in the following sequence:
1. Set the left hand switch at
n.
2.
Join the leads together.
3.
On
the n x 1 range adjust zero by means
of
the knob
marked n x 1.
4.
On the n x
100
range adjust zero by means
of
the knob
marked n x 100.
5.
On
the n x 1
Ok
range adjustzero by means
of
the knob
marked n X 1
Ok.
To test a resistance, set the ri
ght
-hand
sw
itch at the range
required, the leads
be
i
ng
connected across the unknown
component.
Resistance is
re
ad directly on the n x 1 range but readings
should be multiplied by 100
and
10,000 on
then
x 100and
n x 1
Ok
ranges respectively.
If on joining the leads together it is impossible to ob
ta
in
zero
ohms setting, or
if
the pointer position
will
not re-
ma
in constant,
but
falls steadily, t
he
internal battery
or
cell concerned should be replaced. It is important that a
discharged unit should not
be
left in the instrument, since
it
might cause damage
to
the meter. If
it
is impossible to
obtain readings on the n x 1 and n x 100 ranges, the 1A
fuse located in
the
battery box should be checked.
NOTE: A 15V battery
may
age
in such a manner that al-
though
it
indicates a potenti
al
of 15V, its internal resistance
has
increased so much that some loss
of
accuracy can
occur on the high resistance range (!l
.x
1
Ok).
If
erro
rs
are
suspected on the high resistancs range, remove the
battery and check its short circuit current on the 1
OOmA
de range.
If
the reading is below than 25mA
it
should be
discarded.
5
OPERATION
INSULATION
RESISTANCE
MEASUREMENT
High resistance measurements may be made using an
external
de
voltage
of
the order of
140
/160V. The left-hand
switch should
be
set at n
with
the right-hand switch
at
INS and the meter leads should be connect
ed
to
the
battery. The pointer should be brought to
zero
on the
ohms scale by means of the adjuster marked n x 1
Ok
. To
test, connect the unknown r
es
istance in series
with
the
meter and its value
will
be
that shown on the ohms scale
multiplied by 1
00,000. Resistances up
to
200 mego
hms
can. therefore. be
read
on this range.
DECIBEL
MEASUREMENTS
The graph on
Page
7 can
be
used
to determine the dB
va
lu
es
corresponding to
r.m
.s.
voltage
va
l
ues
across a 600
ohm
resis
tive load. A dB value is defined
as
the number of
decibels above
or
below a reference level of 1mW in 600
ohms at 1kHz. Zero dB, therefore,
would
indicate a power
level
of
1mW;
10dB, 10mW, 20dB, 100mW. Because
dB
are defined with respect to a 600 ohm load, power levels
correspond to voltage levels. Decibels can
be
measured in
ter
ms
of
r.m.s. voltages across a 600 ohm resistive load.
For exampl
e,
0.775V
r.m.s.
indicates
OdB
and 7.75V r.m.s.
indicates 20dB. Whilst these measurements must
be
made
with a
si
ne waveform to avoid waveform error, any fre-
quency
may
be used within the range
of
the Model 8
Mark
5.
The decibel and ear response curves have their
closest correlation at 1kHz.
6
Power levels can
be
read
along the top
of
the graph.
If
the r.m.s. voltage is measured across a resistive load
other than 600 ohms t
he
correction factor given below
must
be
added algebraically to the
dB
values
read
from the
graph. The following formula should be used for deter-
mining the correction fact
or.
C . 0
600
orrect1on
Factor= 1 log,0 -
10R
where R is the load in ohms.
If
R is greater than 600 ohms
the Correction Factor is negative.
POLARITY
REVERSE
CONTROL
If
de voltage is required both positive and negative to a
reference point, or the direction
of
current
flow
may
be
reversed, in order to simplify the matter
of
lead alteration,
a polarity reverse
press
button
(REV.
M.C.) is provided.
It should
be
noted that the polarity marked on the terminals
is for normal
use
and does not apply when the red
sec
tion
of
the
REV.
M.C. button can be
seen.
OVERLOAD
PROTECTION
On
e
of
the most attractive features
of
the instrument is
the provision of
an
automatic
cut-out
which gives a
ve
ry
high degree of overload protection, and imparts to the
user a feeling
of
confidence.
dB
+60
I
+55
+50
+45
+40
+35
+30
+25
+20
+15
+10
+5
0
-5
-10
-15
0·1
lr
i+I+H
1111111111
I
DECIBEL CONVERSIONI
GRAPH
r-.
AVOMETER
MODEL
8
MARK
5
~
100W
~
-
lOW
30
Volt Range
/
-
lW
-
· +9:45dB
"II
I/
~
10
Volt Range
lOOm
w
-
+10·4
6dB , -
•
lJ"
}?,OJw
II
3 Volt Range
1mW
Ran
ges
with ratio 3·
0·1
increase-
9·54dB. e.g.
10
to
30V
Ranges with ratio 3:33:1 inct9aS8 =
10
.46<18.
e.g.
3
to
10V
I
Odb
Reference;
o-n40
on
3 Volt Scale= 1mW into
GOOn
0·
1m
W
ji'J
II
II
I I I I I I I I I I LL LJJJL _
I_
-2
·3
·4 ·5 -8
1·0
2·0
3 4 6 8
10
20
30
40
60
100
...__
OPERATION
If
an overload is applied to the meter, either forward or in
reverse, the cut-out knob springs from its normal position
in the panel, thus breaking the main circuit and the
red
portion
of
the
cut-out
knob will show. This knob
has
only
to be depressed
to
render the instrument again ready for
use.
It is important
to
note that the cut-out should never
be
reset when the instrument is connected
to
an external
circuit, whilst the fault which
has
caused the overload
should be rectified before the meter is reconnected.
Although the overload mechanism giv
es
almost complete
protection
to
the meter,
it
cannot be guaranteed to com-
pletely fulfil its function in the very worst
cases
of
misuse,
such
as
the mains being connected across the meter when
set to a current range.
It
should
be
noted that mechanical
shock
to
the instrument
will
sometimes trip the
cut-out
mechanism. Additional protection is provided on resistance
ranges by a fuse connected in the
nx
1 and i1x100ranges.
WARNING
Special care must be taken when using the
instrument
to
service television receivers
or
otherapparatus
employing capacitors
of
large capacitance,
for
the inclu-
sion
of
such components in a circuit may mean that very
heavy peak currents may
flow
when the apparatus is
switchedon. Such surges produce a peaky wave form
and
although these peaks are only
of
a
few
milli-seconds
duration, they may, never-the-less, damage the Instru-
ment diodes.
8
EHT
MEASUREMENT
CAUTION:
It
is recommended that neither the meter.
multiplier
nor
leads are handled whilst high voltage tests
are
in
progress.
Using
the
Combined
10kV/30kV
Multiplier
A combined 1
OkV
and 30kV de multiplier is available for
use
with theinstrument.The Multipliershould
be
connected
to
theAVOMETER set
to
the1
OV
derange. Itis recommend-
ed thatthe meter is kept as near earth potential
as
possible
and the Multiplier
used
at
the high potential end. e.g.
when measuring
an
e.h.t. voltage when the negative line is
earthy, the Multiplier should be connected between the
point of positive potential and the positive terminal of the
meter.
In
addition, the
low
potential end
of
the meter must
be
connected
to
the
low
potential
of
the supply being
measured using the
low
potential lead provided. A cap is
provided which should always
be
in position over the high
voltage terminal not in
use
.
A resistor connected permanently across the multiplier
terminals prevents the full voltage being present should the
meter be disconnected.
General Note: When measuring high ac and de voltages
(say above
SOOV)
unless the common negative terminal is
either earthy or connected
to
earth, errors
will
be intro-
duced
if
the instrument is touched during a reading.
OPERATION
Usi
ng
the
30kV
Probe
Multiplier
A 30kV de Multiplier is available for
use
in series
with
the
meter set
to
its 1
OOOV
derange, readings being madedirect
in kV on the
0-100
scale and multiplied by 300.
It
is most
important to ensure thatthe meter is kept in the earthy end
of
the circuit and the multiplier connected
to
either the
positive
or
negative terminal whichever is at high potential.
This method
of
connection
to
get forward pointer indica-
tion
with
the meter earthy is recommended
as
we
do
not
think
it
desirable
to
use the moving coil reverse button
when measuring high vol
tage.
A special lead is provided
with
the multiplier for connection
to the high potenti
al
point.
HE
AVY
AC
CURREN
T
MEASUREMENT
AC Currents between 1
OA
and
600A may be measured by
use
of
the
AVO
Multi-range Current Transformer (Pt. No.
45869).
Fu
ll operating instructions for its
use
are packed
with the optional accessory.
HEAVY
DC
CURR
ENT
MEASUREMENT
D.C
. currents between 1
OA
and 600A may
be
measured
by
use
of
the appropriate
AVO
DC
Shunt accessory.
When used with the AVOMETER 8
Mk
5,
the shunts
produce a voltage drop of 1
OOmV
when
pas
.sing current
at
their maximum rating.
The Shunt should be connected by means
of
its
two
main
terminals in series with the circuit
to
be measured. The
meter set
to
its
50!1-A
(1
OOmV)
de position should then be
connected
to
the
two
small studs on the shunt end blocks.
The AVOMETER when so set, consumes only
5011-A
at full
scale deflection, a value which is negligible in comparison
with
the full scale current
of
the shunt. The millivolt drop
across the shunt is directly proportional
to
any current
which may
flow
through
it
and since the deflection on the
meter is directly proportional
to
the millivolt drop across
the terminals, the instrument indicates correctly over
its
enti
re
scale length.
NON-SINE
WAV
EF
ORMS
In
as
much
as
rectifier movingcoil instrumentsgivereadings
on 'ac' proportional
to
the mean and not the r.m.s.
va
lue
of
the waveform
with
which they
are
presented, they depend
f
or
their accuracy, not only upon their initial calibration,
but also upon the maintenance
of
a sinusoidal waveform.
Since the form factor (r.m.s. value divided by mean value)
of
a sine wave is 1.11, this
has
been taken into account in
calibrating the meter, which does, therefore, indicate r.m.s.
values on the assumption that the normal sine wave
wil
l be
encountered. Generally speaking, considerable waveform
distortion can occur
without
appreciably affecting the form
factor and resulting accuracy
of
measurement,
but
the user
should recognise the possibility
of
some error when using
distorted waveforms, squarish waveshapes producing
high readings and peaky ones,
low
readings.
9
DESIGN
FEATURES
DESIGN
AND
CONSTRUCTION
The instrument comprises a moulded panel on which are
mounted the whole of the switching apparatus, the move-
ment and other components. A carrying strap is fixed
to
moulded lugs on the rear
case.
The front panel is fitted
into this
case
with a dust proof joint. The switches
are
of
generous and robust design, the contacts being arranged
to
'make'before 'break' on adjacentranges; a feature which
provides a factor of safety in
use.
When the instrument is set for operation on de the moving
coil is associated
with
a universal shunt and series
mu
lti-
pliers, whilst on
ac,
diodes and a transformer
are
al
so
intro-
duced.
RANGE CONTROLS
The left-hand knob provides all the de current and voltage
ranges (except 3000V) and the right-hand knob the ac
ranges (excep't 3000V) and also the resistance ranges.
These knobs
are
electrically interlocked
so
that readings
can only be made after
ac
or de measurement and range
has
been selected. Resistance tests require the left-hand
switch
to
be set
ton
and the right-hand one to the desired
range.
The ranges are marked on the panel and arrow heads
in-
dicate the actual range selected. The 3000V ac and de
ranges
are
available at the
two
3000V terminals.
10
Wide coverage in resistance
has
been achieved by having
a fundamental range
as
marked on the scale, together
with
ranges
of
x 100and x 1
Ok
to
supplement
it
.
In
addition a 200 megohm range marked INS is available,
using an external
de
voltage source (See
Page
7)
.
THE
MOVEMENT
The meter movement in the Model 8 Mark 5 is a robust
AVO
centre pole movement type ACP1, fitted
with
spring
mounted jewelled bearings and impregnated coil. The
meter
has
a full
sca
le deflection
of
37.5v.A. A knife edge
pointer enables very fine readings to
be
taken, whilst the
whole movement
is
balanced and damp
ed
so that the
pointer quickly comes to rest.
SCALING
The scale plate
has
three main sets
of
markings.
One
is for
resistance measurementand ismarked 0 to 2000 ohms, the
second is for current and voltage (both ac and de) and is
marked 0
to
10
whilst the third scale calibrated 0
to
3
has
60 divisions and is used for current and voltage
measurements.
SERVICING
YOUR
AVOMETER
REPLACEMENT
OF
BATTERIES a
nd
FUSE
By
turning
the!
turn fastener on the back
of
the instrument
until the slot is vertical the 15V battery, 1.5Vcell, 1A fuse
and spare fuse
are
easily accessible. The batteries should
be examined from time to time to ensure thatthe electrolyte
is
not
leaking.
If the meter is going
to
stand unused for several months,
the batteries should
be
removed.
When replacing the 1.5V cell and the 15V battery they
must
be
inserted in the correct polarity.
Suitable
re
placement batteries
are
list
ed
on
Page
3.
PLUG-IN
TYPE LEADS
When ordering replacements, the full description and Part
numbers should be quoted.
AVO
REPAIRS
DEPARTMENT
Due
to
the high standards maintained
th
roughout
our
organisation, breakdowns are comparatively rare and can
often be traced
to
transit damage or careless handling,
for
which thecompany cannotbe held responsible.
If
however,
your instrument should require servicing or a calibration
check, we
at
AVO
have the knowledge and equipment
to
repair your instrument to the highest possible standard.
For those customers
who
feel they have the necessary
skill and equipment
to
carry
out
their
own
servicing
requirements. spares are available from
Avo
Limited.
To obtain the correct spares item, identify the component
required and state its position on the instrument. Where
applicable state the circuit reference number. Should you
at
any time have to return your instrument
to
the Company
for repair, pack
it
carefully and enclose a note informing
our engineers
of
the faults which you
have
found.
Custo
~
mers
outside the U.K.shouldcontactthe
AVO
representative
for their territory. ·
11
SERVICING
YOUR
. AVO
METER
TABLE OF
COMPONENTS
R1
18.40
R22
6M!l
R2
2.16k0
R23
8MO·
R3
62k!l
R24
40MO
R4
180k0
R25 4MO
R5
1
.8MO
R26
20k0
R6
7k0*
R27 Movement
R7
5000*
swamp
R8
5k!l*
R28
5k0*
R9
0.040}
R29,
R30
8890
R10
0.360
Printed
R31
2700
Shunt
R11
3.
60
RV1
15k!l
R12
360
RV2
15k!l
R13
3600
RV3
18k0
R14
933.30
R15 6.667k0 01,
02
OA95
R16
58k0
C1
220pF
R17
140k0
C2 0·
015!LF
R18
400k!l
C3
470pF
R19
600k!l
R20
800k!l
81
1.5V
R21
4M!l
82
15V
Movement
Avo
large centre pole
• Adjusted on calibration. Type
ACP1
12
CIRCUIT
DIAGRAM
lli
M'OI"-~
""
• " l
lln
...
.
........
0
+
..
...
..
..
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0°6
~
~
----------
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~
~
v~
w~
;
;
®
.,.
ot
LJ
0
••,•,
•
--
~
~~)
~~
~•
~
}
••
1
~
•
~----------------
----
----
-+
~~+---------
----
--
----,
•:w.f•{
V.
\.::1
~
.
~
.
~
---+
-
~~~LJ.~
·
·
···
~
0
.,
0
ti
,
...-----
- - .,. .
;:
-rl-
f.
.
~
......-
••.
,. .
--1-
_+---.:c
~
i
"
...
.
0 •
0"
41
"'•""
•
1t
(!),
(!)c.o-"K
•'If
@
•
(i)c-'-~
0 •G>c:-··
c.·
(i)
•
(!')c.-.C,..
n
St-0
c..-sw
.
~:e
3 •9C>.otnn •
fM
•W
(9
•9 Co
OHt
•n o
M,JO'
®•9
C:o_t.Atl
·
-~
<I>
·
~,,
.
..
....
_.
(!).~
(IOW
O'bot
'
•
•
Avo Limited Dover, Kent CT17 9EN
England
Tel:
Dover (STD 0304) 202620
•
Telex: 962.83 AVO
(Ans : Measurement Dvr)
Cables:
Measurement Dover ,
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