Elenco Digital Mulitmeter Kit - Manual (Page 14)

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Figure 2
7106 IC Functions
Figure 3
a
b
a
b
c
d
e
f
g
TYPICAL SEGMENT OUTPUT
0.5mA
2mA
V+
Segment
Output
Internal Digital Ground
LCD PHASE DRIVER
LATCH
7 Segment
Decode
7 Segment
Decode
7 Segment
Decode
Thousand Hundreds Tens Units
*
CLOCK
To Switch Drivers
From Comparator Output
-4 LOGIC CONTROL
Internal Digital Ground
200
BACKPLANE
28
V+
TEST
V
500 Ω
3
8
6.2V
1V
* Three inverters.
One inverter shown for clarity.
7 6 4
OSC 1 OSC 2 OSC 3 DIGITAL SECTION
ANALOG SECTION of 7106
C REF R INT
C AZ C INT
INT C REF + REF HI REF LO C
REF BUFFER V+
35 42 44 43 41 36 37 1
AUTO
ZERO
+
A-Z &
Z1
A-Z &
Z1
A-Z
DE (+)
DE (+) DE (-)
DE (-)
IN HI
COMMON
IN LO
40
39
INT
10 μ A
V+
38
INT
+
+
+
2.8V
A-Z & DE(+)
& Z1
34
V
Z1
6.2V
A-Z COMPARATOR
ZERO
CROSSING
DETECTOR
POLARITY
FLIP/FLOP
TO
DIGITAL
SECTION
INTEGRATOR
+ REF
(Flying
Capacitor)
Unknown
Input
Voltage +
Read
Integ.
AZ
AZ
Integ.
To
Digital
Control
Logic
AZ Integ. Read AZ
+.20
.15
.10
.05
0
1000 0
160ms Counter Output
0 500 1000 1500 2000
DUAL SLOPE A/D CONVERTER