User guide

PIN FUNCTIONS
1. V+ Positive powersupply connection.
2. V- Negative power supplyconnection.
3. INHI Positive measuringinput with referenceto IN LO.
4. INLO Negative measuring inputwith reference toIN HI.
5. XDP Connect to DP1,2 or 3to display required decimalpoint.
6. DP1 Connect to XDPto display DecimalPoint 1(199.9).
7. DP2 Connect to XDPto display DecimalPoint 2(19.99).
8. DP3 Connect to XDPto display DecimalPoint 3(1.999).
L1 Normally Closed,connects COM toINLO.
Solder Links:
CIRCUIT DIAGRAM
V 125 3½ Digit LCD Voltmeter Module
Analogue inputs must be no closer than 1V
to either the positive or negative supply.
V+
1
6
7
8
5
3
4
2
V+
V+
INHI
INLO
V-
L1
DP1
DP2
DP3
XDP
INT
V+
V-
TEST
27
1
26
28
29
31
30
32
34
39
40
38
33
DP1
LOBAT
199.9
DP2
19.99
DP3
1.999
BUF
A/Z
IN HI
IN LO
COM
CREF+
CREF-
36
REF HI
35
REF LO
OSC1
OSC2
OSC3
IC1
LCD1
R9
1M
R6
100k
R11
100k
R10
100k
Q1
3904
R3
100k
C5
100pF
C4
100nF
C1
68nF
R1
300k
R2
1M
C2
220nF
C3
100nF
R5
3k
R4
1.5k
R8
1M
R7
1M
a1
a1
d1
d1
e1
e1
f1
f1
g1
g1
f2
f2
a2
a2
g2
g2
e3
e3
b2
b2
a3
a3
f3
f3
c2
c2
b3
b3
g3
g3
d2
d2
c3
c3
bc4 ab4
e2
e2
d3
d3
b1
b1
c1
c1
524
220
819
625
722
13 1
12 28
25 26
18 10
11 27
18
13
9
6
23 3
17 4
10 17
16 2
22 5
916
24 12
19 8
14 14
15 11
423
321
37
POL
POL
BP
COM
20 7
21 15
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