HP 3438A Operating And Service Manual page 74

- - -
D@itully
nmostrncd
by
Artckkdm
@
2W?-2OYM
-
- -
-
-
A C
VOLTS
F U N C T I O N
- - I
I
/ -
INPUT AMPLIFIER
=
I I
/ - P O S T A M P - \
/ =
AC TO DC CONVERTER
= \
OH3
=-@
/
A TO D CONVERTER
-
I
A REF.
500mV
ADJ.
RH210
1.15M
- - - - - -
I
A M P S F U N C T I O N
D C V O L T S F U N C T I O N
AC VOLTMETER
I
s 4 t c
a
D )
S8(A) SHOWN I N dc VOLTS FUNCTION
WlTH 2OOmV RANGE SELECTED.
90C 54181
A M P L I F I E R - \
0
g i % :
dc
0
COMPARATOR
?AUTO Z E R O =
n DC VOLTMETER
I
/ I N P U T
SHOWN IN DC MlLLlAMPS
FUNCTION WlTH ZOOMA
RANGE SELECTED.
p 4 9
STATE CHANGING
SWITCHES
-
-
-
- -
-
- -
OHMS F U N C T I O N
I
SHOWN IN OHMS FUNCTION WlTH
2 K n RANGE SELECTED.
I
I
OHMS CURRENT SOURCE -
3 ~n
REF
OHMS SENSE CURRENT I K
R1i9
t 5 0 0 m V
I
1 T 1
lb
/ - I N P U T A M R I F I E R P \
+. 5 V
7
OHMS PROTECTION
7
CLOSED
FOR 2 O M n
IOOK d 9 5 M OV
REF
CLOSED FOR
O
I
M
h e
ZERO
IOOK ADJ
I I
I
1
CLOSED FOR 2 0 K n RANGE
Lj
1 1
! ? :
1
I
CLDSED FOR 2 K n RANGE
-
-
IK
I
Figure 8-1 2. Simplified Analog Schematic.
8-1.518-16