Advertisement
MODEL 6000 ELECTROMETER
OPEKATION
SWTION
2.
OPERATION
2-1.
INPUT CONNECTIONS. The Model 6008 INPUT Recep-
cacle
is a Teflon-insulated
UHF connector.
A shield
cap is provided.
The ground
posr,
below ehe Recep-
tacle,
is conneceed
co chassis
ground.
a.
The accessories
described
in Sectton
5 are de-
signed
co increase
rhe accuracy
and convenience
of
input
connecfions.
Use them eo gain
rhe maximum c=p-
ability
of rhe Model 6008.
c.
Use hixh
resisronce.
low-loss
marerials
-
such
as 'Teflon
, recommended,,
polpe~hylene
or oolpsqrene
-
for
insulation.
Insuinci""
leakage
resiseance
of
test
fixtures
and Leads shouid
be several
orders
of
magnitude
higher
than rhe internal
resistance
of the
SOUrCe.
Excessive
Leakage reduces
the accuracy
"i
reading
irom nigh
imoedance
sources.
coaxi
cabies
used should
be II io" noise
type whici,
employ a graph-
ite
or ocher
conducrive
coacinq
berrreen
the dieiectric
.Ind ehe surrounding
shield
or=id,
An+2nol-Sorg
Elec-
tronics
core.,
?,icr"do~,
I:::.
, _.." "_...r.-..
..LL5 aLIu
lz-lble co. make socisixcory
types.
NOTE
Clean,
dry connecrions
and cables
are very
im-
porcaoc
to maincain
the value
oi 311 insularion
materials.
Even the besr insulation
will
be com-
promised
by d"SC. cirrc.
so,oer
Tl"X,
LilrnS of
oil
or water
vapor.
A good cleaning
agent
is
methyl
=lcohoi.
which disolves
most common dirr
wirhour
chemic=lly
acr=cking
the insulation.
:,ir
dry
the cables
or ~onnecei""s
after
uashing
vith
alcohoi
or "se dry nirrogen
if
available.
Or,
if
available,
Freon is an excellent
cleaning
agent.
d.
When working
with
a high
impedance
source
any
change
in shunt
cnpaci~once
of the input
circuit
will
cnuse disturbances
in the reading.
Nake the messuring
sefup
as rigid
as possible,
nnd eie down connecting
cables
to prevent
their
,!?A~iL%iii..
;\ i~il.illY"Ub
"LYLA-
tion
may appear
8~ the outpur
as a sinusoidal
signnl,
=nd orher
precaurions
may Le necessary
co isolace
rhe,
insrrumenc
and connecting
cnble
from the "ibra+zton.
e.
For low impedsnce
meesuremencs
-
below
LOS
ohms or above
LO-8 ampere -
unshielded
leads
may be
used and a binding
post
adapeer
may be used.
however,
keep the leads
short.
f.
When the Model 6008 is used on the most sensi-
tive
current
range with
the FEEDBACK Switch
=e FAST,
Borne insulators
-
4uch as Teflon
-
may produce
ran-
dom signals
which
show up as erratic
meter deflections.
InsulaCion
used in the Model 6008 is carefully
seiec-
ted LO minimize
these
spurious
signals.
g.
If
a well
shielded
chamber
and a well
made high
impedance
transfer
switch
is
available
it
is
advantage-
ous CO connect
ehe Model 6008 to the circuit
only
when
a reading
is being
made.
In ~"me cases,
rhe offsee
current
can charge
the external
CASE circuifry.
ilne
e::ample
of this
occurs
when measuring
a capacitor'5
leakage
resistance
by observing
the decay of the ter-
minal
voltage.
If
rhe leakage
c~rre":~is
less
than
the offset
current
(Less
thnn
2 :< LO-
smoere,
there
may be no decoy of the terminal
voltage
when ehe Elrc-
trometer
is left
connected
across
the copacicor's
fer-
"i"8iS.
XOTE
Keep the shield
cao on the INPUT aeceofocle
when the ~leccromerer
is nof
in use.
3-2.
PRELMINARY PROCEDURES.
8.
Check battery
condition
by holding
the llETER
Swirch
tn the S,,TTER,' CHECK position.
Turn the ilul-
ciplier
Switch
eo 10, 3 end I pOsitiOns
=nd observe
one meter
readings.
The meter
shoutd
read one-haii
of fllll
'.-.!e
or more in ench Nuleiplier
switch
?"Si
tion.
Table
f. show
the batferies
checked
by each
POSiCi"".
Ii
rhe reading
for
any baccery
is below
one-i,alf
full
scale,
replace
the indicated
baetery.
TABLE 4.
Nultiolier
Switch
Positions
far
Checking
Conditions
of SatCaries.
SaeCeev Checked
10
BA103 di DA104
3
SAlOl
6. k4102
1
Ml05
b.
Set the controls
as follows:
ZERO CHECK nutcon
Range Swirch
EUICI~L~~~
Switch
FEEDBACK Switch
METER Switch
LOCK
VOLTS
1
NORMAL
POWER OFF.
.c.
Turn the METER Switch
to CENTER ZERO. Within
ten seconds,
ehe meter
needle
should
come co the ce"-
0872R
3
Advertisement
