Elenco Electronics EP-130 - Resistance Tester

-
148
-
If you use a meter you can find the exact value of
a
resistance; but when you only want to know
approximate resistance values, you can use thi
s
resistance tester
.
This circuit converts resistance to electric current an
d
c
om
p
ares it with the com
p
arator’s reference current
to tell you the approximate range of resistance. Th
e
c
omparator has a reference volta
g
e of about 0.82V.
B
u
ild
t
h
e c
i
rcu
i
t an
d
set t
h
e sw
i
tc
h
to pos
i
t
i
on
A.
Connect the material to be tested between terminals
1
3 and 14. The LED lights i
f
the resistance is les
s
t
h
an 100
k
Ω
, otherwise it is o
ff
. I
f
the LED li
g
hts,
connect terminals 93 and 86. I
f
the LED turns o
ff
no
w
the resistance is between 1
0
Ω
and 100k
Ω
k
. I
f
it stay
s
on, remove the wire
f
rom terminal 86 and connect i
t
to terminal 84. I
f
the LED turns o
ff
now, th
e
resistance is in the range of 1 to 10k
Ω
k
k
. I
f
the LED stil
l
doesn’t turn off
,
remove the wire from terminal 84
and connect it to terminal 76. I
f
the LED turns o
ff
now, it means that the resistance is in the ran
g
e o
f
100
Ω
to 1k
Ω
k
k
; i
f
it stays on, the resistance is less tha
n
100
Ω
.
N
o
t
es:
EXPERIMENT #12
6
: RE
S
I
S
TAN
C
E TE
S
TER
Schematic
Wiring
S
equence
:

1
3
-
93
-
69
-WIR
E

14
-7
9
-7
0
-
121

75-83-94-90-88-31-63-13
1

33
-
67

68
-
80
-
87

8
5-
89

11
9
-12
4

122-1
32