Keithley 153, Instruction Manual, Page: 28 / 51

S ERV IC ING
V 20 1
P l a t e
2 2
M '
1 000 u f
C i r c u i t
Gnd
Gr i d
F I GURE
1 3 . Div i d e r Connec t i on f or Mu l t iv i ­
b ra t o r F r e q u e n c y
Adus tmen t .
C
o
n
n
e c t
t h e
d i v id e r t o
e i t h e r p i n 1 o r
6
o f V 20 I a nd
t o
p i n 2
o f
V I0 2A .
Us e
1 % , 1 / 2 wa t t ,
d e p o s i ­
t ed c a rb on res i s t ors
and a
I S - v o l t
c a p a c i ­
t o r f o r t h e
d ivi d e r .
- - -
,
- - -
I
I
MODEL 1 5 3
MI CROVO LT - AMMETER
I
!
-
r
F I GURE
1 4 . Wa v e
F
o
r m o f
Mu l t iv i b r a t o r Ou t ­
pu t . Os c i l l o s c o p e wa s
a t t a c h e d t o p i n
1 o f
t u b e V 20 l A ( F i gu r e
1 9 ) .
V e r t i c a l
s e t t i ng
i s
100 v o l t s / e m ; h o r i z o n t a l , S
ms e c / cm .
SWI TCH
t o
I NPUT
R- 2M.
Us e t h e Mod e l 6 1 0 B t o check
p i n
7 of tub e VIO l for a pproxima t e ly
- 1 . 23
v o l t s ± 10 % .
b . P l a c e t h e r e s i s t o r d i
v
i d
e
r
f r om e i the r
p l a t e
o f tub e V20 l
(
F
i gu
r
e 1 9 ) t o g round .
S e e
F igure 1 3 . C
o n
n e
c t
the
ou t pu t
o f t he d i
v i
d e
r
t o
t
h e g r i d o f tub e V I0 2A ( F igur e
2 1 ) .
Moni t or
t h e
o u t p u t
a c r o s s r e s i s t o r R1 2 l ( F igur e
2
2
)
wi th the Typ e
P60 0 6 Pr ob e .
c . S e t
t h e
RANGE Swi t c h
t o
30
MI LLIVOLT S .
Ad j u s t
t h e
MULTIVI BRATOR
FREQUENCY ADJ
Po t en
t i ome t e r ,
R2 10
( Figure 2 7 ) ,
t o
ob t a in
t h e
la rg e s t s igna l a
c
r
o
s
s
r e s i s t or R 1 2 l ,
approxi ­
ma t e ly
6 . 5
t o 7 . 5
vo l t s
peak- t o - p ea k ( 650 t o
7 50
mi l l ivo l ts
wi th
d iv i d e r Pr o b e ) .
Figur e
14
s hows
t y p i c a l wav e
f orm a t the
mu l t iv i b r a t o r
o
u
t
p u
t
.
Figure
1 5
s
h
o
w
s t y p i ca l
wav e f orm
a
c r o s s Rl 2 1 ( j unc t i on of
R
l
2 1 and C I 1 7 ) . If tun i ng p o t ent i om e t e r R2 10 d o e s not cau s e
the
s i gna l to
swing
through maximum ,
chang e t h e va l u e o
f
r e s i s t o r
R20 8
( F igu r e 2 7 )
to
c en t e r
the
po t e n t i ome t e r
adjus tmen t .
FIGURE 1 5 . W a
v
e Form
for Tuned Mu l t ivibra­
t or Ou t pu t
Acro s s
Re s i s t o r R1 2 1 ( Figure 2 2 ) .
Vert i c a l s
e
t t
in
g is 1 vo l t / e
m
; hor i z ont a l ,
2 mi l l is e cond s / cm .
20
�\
II
\
I
,
I
I
FIGURE 1 6 .
Wave
F
o
r m
for
I npu t Mod u l a tor
ElO l .
The ou tput i s
monit ored a t
pin
2 of
V10 l with a 10 : 1 d ivider
prob e .
Osc i l lo­
scope
i s
de
coup l ed .
Vert i c a l s et t ing i s
20
mi l l ivo l t s / cm ; hor i z on t a l ,
2 mi l l i ­
s econd s /cm.