Keithley 153, Instruction Manual, Page: 7 / 51

MODEL 153
GENERAL DESCRIPTIO:i
SECTION 1. GENERAL DESCRIPTION
I-I, GENERAL.
il,
The
Keithley Model
153
Microvolt-Ammeter is a
v
e
r
s a ti
l
e
dc
ins trument with high inp�t
impedance and low noise for measuring a wide
r
a n
g
e
of
voltages and currents. Its
voltab�
a r
e
from 5 microvolts full scale
to 1000 volts,
and
its current ranges are
from
ampere full scale to 0.1 ampere, The Model
153
has zero�center and ze ro-left met�r
scales.
b, A c
c
u ra c y for the vo l tage ranges varies from
! l%
of full s c al e on the 3-millivolt a��
higher ranges to !3% of fu l l scale on the
10
and 3D-microvolt r ang
e
s.
Accuracy for tile
current
range s varies from
:2%
of full scale
on the 3
x
10-9
ampere and higher
ranges to
!4%
of full scale on
the
3 x
10-11 ampere
and lower ranges.
c,
Input r e si st
a
n c e
is
200
megohms
for
the I-millivo l t and h i g h
e r
ranges.
Input resis­
tance
for the 10-microvolt range is
20
megohm s.
If
a lower res istance
is
wanted,
a
front
panel sw itch co n t r o l allows shunting
a
2-megohm res isto r across the input.
d,
Input noise on the most sensitiv e voltage r
a
n g
e
with the input shorted is less thar.
0,06 microvolt
rms.
noise
on the most sensitive current range with
the
input
open
is l ess than
0.1
x
ampere rms,
1- 2 .
FEATURES.
a,
The
Model 153 has excellent reso lut ion for po ten tiometric null d e t e
c
t o r
applications,
Line frequency r e j ec t io n is good; a power line or twice power
line
frequency
which
is
40 db
(p-" 'c)
g
r eate r than full scale affects readings less
t
h a n
0.5%,
Isolation greater than
109
.. .�
from ground permits use in floating circuits.
h rhe
Model 153
uses the
v
o
l
t
a
g
e drop method
to
m
e asu r
e
currents.
Input
resistance
<],'
... ll
a
nun
e
t e
r varies
from
1 m
e
g
o
h
m on the
10-11
a m p er e range to
1 ohm
on the O
.
l
-
a m p
e
re
range. Voltage drop varies from
10
m
i
c
r
o
v
o
l
t s to 100 millivolts, depending upon the
range used.
c. Recorder output
is ±1
volt dc at up to
1
m
il
li a
m
p e
r
e
for full-scale meter deflection
on any range. The
I-milliampere capability
permits use w i
t
h
recording galvanometers.
Outpu t resistance
is
less than 10 ohms with the output potentiometer set for maximum
out­
put. Drift is less
t
h a n ±2 m i c r o
v
o lt s per
24
hours.
1-3.
APPLICATIONS.
a. As a voltme t er, the Model 153 is ideal for
measuring a
wide variety of vol t a ges such
as contact
potentials,
vacuum tube electrode
p
o t e n t i
a
l
s
, biologically generated emf's,
electro-chemical p otential s , and power supply v ol t a
g
es
.
Other applications include use
wit
h
variou s voltage generating transducers such as piezo-electric generators, Hall effect
generators
and
strain gauges.
b. The 110del
153 is
also ideal
for
most null d e t e
c
t o r
applications, On
the
three
most
sens itive ranges, power sensitivity is bet ter t han 5 x 10-21 Ka t t.
High
ae
rejection
and
flo a ting
capability
m
a
k e the Model
153
an
i d e
a
l null detector for any bridge or potentio-
meter.
1