Micronta 22-185A User manual
Cat.
No.
22-185A
OWNER'S
MANUAL
Please
read
before
using
this
eguipment
LCD
DIGITAL
MULTIMETER
MICRONTA®
FEATURES
-
The
MICRONTA®
LCD
Digital
Multimeter
is
a
portable
3-2/3
digit,
compact-sized
multimeter
ideally
suited
for
field,
lab,
shop,
bench
and
home
applications.
Here
is
a
review
of
some
of
the
features
that
qualify
your
new
digital
multimeter
as
real
“pro”
O
The
latest
IC
and
display
technology
is
used
to
achieve
the
lowest
possible
component
count.
This,
in
turn,
ensures
reliability,
accuracy,
stability
and
a
really
rugged,
easy-to-handle
instrument.
Two
analog-to-digital
converters
are
used
for
many
special
features.
Conveniently
positioned
range
and
function
switch
knobs
for
one-hand
range/function
control.
4
Colored
indication
of
the
referential
ranges
to
the
selected
function.
Effective
overload
and
transient
protection
on
all
ranges
except
DC/AC
10A
range.
Continuity
function
for
quick
continuity
check
—
buzzer
sounds
when
circuit
resistance
is
approximately
300
ohms
or
less.
©1988
Tandy
Corporation
All
Rights
Reserved.
Micronta
is
a
registered
trademark
of
Tandy
Corporation.
—
CONTENTS
@
Diode
check
function
lets
you
safely
FEATURES
ree
enna
EA
mete
2
check
semiconductor
junctions
for
open,
SPEGIEHCATION
SEA
SA
4
fa
short
or
normal.
CONTROLS
AND
FUNCTIONS
.........
8
PREPARING
FOR
OPERATION
.........
12
O
Over-range
indication
on
each
range.
CHECK
BEFORE
OPERATION
DT
AE
16
MAKING
MEASUREMENTS
...........
18
o
Full
auto-polarity
operation.
EUSEIREPEAGCEMENI
INN
EN.
34
MAINTENANCE.................
hoo
jaat
36
@
Low
battery
voltage
is
automatically
AWN
ORDIABOUTESAFEIVaseanee
ree:
38
detected
and
a
caution
is
displayed.
SCHEMATIC
DIAGRAM
e
risen
42
O
Fold-out
stand
for
bench-top
use
or
for
hanging-up.
Warning:
Use
extreme
caution
in
the
use
of
this
device.
Improper
use
of
this
device
can
result
in
injury
or
death.
Follow
all
safeguards
suggested
in
this
Owner's
Manual
in
addition
to
normal
safety
pre-
cautions
in
dealing
with
electrical
circuits.
Do
not
use
this
device
if
you
are
unfamiliar
with
electrical
circuits
and
testing
procedures.
SPECIFICATIONS
Ranges
&
Accuracy
DC
VOLTS
300
mV-3-30-300-3000
V
+0.8%
of
reading
and
(Maximum
Measurement
+0.2%
of
full
scale,
=
1000
Volts)
+1
in
last
digit
AC
VOLTS
3-30-300-3000
V
+1%
of
reading
and
(Maximum
Measurement
+0.5%
of
full
scale,
=
750
Volts
RMS)
+1
in
last
digit
at
50/60
Hz
45
Hz
to
500
Hz
+1.5%
of
reading
and
at
30
Volt
Range
+0.5%
of
full
scale,
+1
in
last
digit
500
Hz
to
10
kHz
+10%
of
reading
and
at
30
Volt
Range
+0.5%
of
full
scale,
+1
in
last
digit
Specifications
DC
CURRENT
3-30-300
mA-30
A
+1.5%
of
reading
and
IN
(Maximum
measurement
=
10A)
<
+0.2%
of
full
scale,
+1
in
last
digit
AC
CURRENT
3-30-300
mA-30
A
+1.5%
of
reading
and
(Maximum
measurement
=
10A)
+0.5%
of
full
scale,
+1
in
last
digit
RESISTANCE
300
ohm-3-30-300-3000
kohm
+1.5%
of
reading
and
+0.2%
of
full
scale,
+1
in
last
digit
+5
digits
maximum
at
300
ohm
range
30
Megohm
+3%
of
reading
and
+0.2%
of
full
scale,
+1
in
last
digit
Specifications
Continuity
Function:
Input
Impedance:
Range
Selection:
Power
Source:
Power
Consumption:
Diode
Check
Function:
Low
Battery
Indication:
Continuity
buzzer
sounds
at
less
than
295
ohm
(£20
ohm)
input
resistance.
Buzzer
sounds
100
ms
—
150
ms
(typical)
after
input
is
|
shorted.
For
checking
semiconductors
open,
short
or
normal.
10
Megohm
(DCV/ACV).
More
than
100
Megohm
on
300
mV
DC
Manual
range
Four
“AA”
size
1.5V
batteries,
providing
+3V
10
mW
typical
“BATT”
on
the
left
of
display
indicates
when
+
or
—
supply
is
below
2.4V
—2.6V.
Polarity:
Ä
yes
Indication:
Operating
Temperature:
Storage
Temperature:
Weight:
Size:
Accessories:
Automatic
polarity
3000
with
blinking
“3”.
When
the
measured
value
exceeds
the
maximum
value,
all
digits
on
display
will
blink.
3242F
10
122°
F(0°C
to
50°C)
—4°F
to
140°F
(20°C
to
60°C)
11.6
oz.
(330g)
6-3/4"
X
3-1/16"
X
1-1/4”
(170
mm
X
78
mm
X
32
mm)
Fuse
(0.5
A/250
V)
Banana
type
test
leads
(Cat.
No.
278-704)
CONTROLS
AND
FUNCTIONS
—
än,
AC!
at
OF
Ct
CI
mAn
Aa
Am
Qa
O»
3
30
300
3000
1.
Digital
display:
a.
Low
BATTery
indicator
—
lights
when
batteries
ar
(
weak
and
need
replacing.
b.
AC
indicator
—
lights
when
you
select
the
AC
voltage/current
measurement.
c.
Measured
input
values
—
shows
the
measured
value
with
decimal
point
and
minus
polarity
indication
(2999
maximum.)
d.
Measuring
unit
indicators
—
lights
to
show
the
current
measuring
unit.
e.
Diode check
indicator
—
lights
in
the
diode
check
mode.
f.
Continuity
indicator
—
lights
during
the
CONTINUITY
check
mode.
2.
Power
switch:
Turns
the
meter
ON
and
OFF.
Set
to
a
for
continuity
check.
l
3.
Range
switch:
Used
for
selecting
ranges:
Voltage:
DC
V
300mvV,
3V,
30V,
300V,
3000V
(Maximum
measurable
voltage
is
1000V.)
AC
V
3V,
30V,
300V,
3000V
(Maximum
measurable
voltage
is
750V.)
Current:
3mA,
30mA,
300mA,
10A
Resistance:
3000hm,
3kohm,
30kohm,
300kohm,
3000kohm,
30
Mohm
Diode
Check
4.
Function
switch:
Used
for
selecting
functions:
DC
V,
AC
V,
Diode
CHECK,
kohm,
DCmA
and
ACmA.
©
&
MICRONTA
DIGITAL
MULTIMETER
IN
CONTINUITY
cree
OR
-COM
E
oyoo
AMPS
750V
AC
ONLY 790V
A
300mA
IOA
MAX
VEN
MAX
UNFUSEO
E)
Controls
and
Functions
Controls
and
Functions
5.
Input
(10A)
jack:
Connect
(+)
red
lead
for
current
measurement
with
the
10A
setting
of
the
range
switch.
|
000V
DC
750V
300mA
OF
D
Oa
ZO
6.
Input
(—)
jack:
Connect
(—)
black
lead
for
all
measurements.
7.
Input
(+)
jack:
Connect
(+)
red
lead
here
for
all
measurements
except
10
A
range.
8)
9
8.
Battery/fuse
Compartment
:
Open
to
install/replace
fuse
and/or
batteries.
9.
Fold-out
Stand:
Use
to
support
the
multimeter
at
a
convenient
viewing
angle
for
benchtop
use
or
to
hang
It
up.
10
Special
Panel
Markings
Controls
and
Functions
AC/DC
AMPS
ONLY
10A
MAX
UNFUSED
750V
1000V
DC
750V
AC
300mA
MAX
4
Special
markings
has
been
added
to
the
panel
to
remind
you
of
the
measurement
limitations
and
safety.
The
maximum
current
that
can
be
measured
is
DC/AC
10A.
10A
range
is
not
fuse-protected.
To
avoid
electrical
shock
and/or
instrument
damage,
do
not
connect
the
common
input
terminal
(-jack)
to
any
source
of
more
than
750V
with
respect
to
earth/ground.
Refer
to
complete
operatng
instructions.
The
maximum
voltage
that
can
be
measured
is
1000V
DC
or
750V
AC.
The
maximum
current
measurement
at
this
terminal
is
300
mA.
Be
extra
careful
when
making
measurements
for
high
voltage;
DO
NOT
TOUCH
TERMINALS
OR
PROBE
ENDS.
PREPARING
FOR
OPERATION
Installing
Batteries
12
All
you
need
to
do
is
load
four
1.5V
“AA”
batteries.
We
recommend
that
you
use
the
alkaline
type
—
such
U
our
23-552.
N
1.
Be
sure
POWER
is
OFF
and
test
leads
are
disconnected.
2.
Push
the
arrow
on
the
battery/fuse
compartment
cover
and
press
in
the
direction
of
the
arrow.
3.
Snap
the
batteries
in
place
—
watch
polarity!
4.
Press
the
cover
back
into
place.
Preparing
For
Operation
When
the
batteries
become
weak,
“BATT”
will
be
isplayed
on
the
left
part
of
the
display.
Replace
all
the
Wa
NEVER
LEAVE
WEAK
OR
DEAD
BATTERIES
IN
YOUR
UNIT.
Even
“leak-proof”
types
can
leak
and
cause
damage
to
the
circuitry.
When
you
are
not
going
to
use
your
unit
for
a
few
weeks,
remove
the
batteries.
BATT
3
30
300
23000
13
Preparing
For
Operation
Using
Test
Leads
Test
Leads
(Cat.
No.
278-704)
Use
only
the
same
type
of
the
test
leads
as
are
supplied
with
your
unit.
These
test
leads
are
rated
for
1200
volts;
replacements
are
available
from
your
local
Radio
Shack
store
(Radio
Shack
Cat.
No.
278-704).
Caution:
Although
these
test
leads
are
rated
for
1200
volts,
the
maximum
rating
of
this
meter
is
1000
volts
DC/750
volts
AC.
You
should
not
attempt
to
measure
any
voltage
more
than
1000
volts
DC/750
volts
AC.
Use
extreme
care
when
using
these
high
voltage
ranges.
14
Using
Stand
The
fold-out
stand
allows
you
to
use
your
unit
on
the
benchtop
or
hang
from
a
hook.
Preparing
For
Operation
Stand
Positions
and
Their
Usage
Bottom
Wall
Note:
To
fold
the
stand
upwards
from
the
middle
position,
press
at
the
lower
parts
on
both
sides
slightly,
then
turn
upwards.
The
stand
can
be
removed
by
pressing
the
lower
parts
strongly.
15
CHECK
BEFORE
OPERATION
1
OFF
ON
CONTINUITY.
1.
Set
the
power
switch
to
ON.
All
the
elements
of
the
display
will
appear
on the
LCD
briefly
as
a
self
test.
The
||
[0]
|
display
will
soon
revert
to
normal.
|
2.
Set
the
function
switch
to
kQ.
3.
Rotate
the
range
switch,
starting
at
the
top
(30
MQ).
The
decimal
point
in
the
display
should
be
positioned
as
described
in
the
chart
on
next
page:
Notes:
1.
In
low
voltage
ranges,
with
leads
unconnected
to
any
circuit,
the
display
may
show
some
“phantom”
readings.
This
is
normal
and
is
caused
by
the
high
sensitivity
and
high
input
impedance
of
the
meter's
circuitry.
As
soon
as
a
circuit
is
connected,
normal
accurate
measurements
are
performed.
16
Check
Before
Operation
Functions
Display
pcan
DCV/ACV
dddd
V
300
V
ddd.d
V
30
V
dd.dd
V
3
V
d.ddd
V
300
mV
ddd.d
MV
(DCV
only)
dd.dd
A
ddd.d
mA
dd.dd
mA
d.ddd
mA
Range
Display
Functions
Range
30
Megohm
|
dd.dd
MQ,
DCmA/
10A
3000
kohm
dddd
kQ
ACmA
300
mA
300
kohm
ddd.d
kQ
30
mA
30
kohm
dd.dd
kQ
3
MA
3
kohm
d.ddd
k
300
ohm
ddd.d
Q
Continuity
320
ohm
(Fixed
range)
ddd.d
Q
2.
See
the
measuring
unit
on
the
display
to
distinguish
the
range
when
two
ranges
have
a
decimal
in
the
same
position.
For
example,
on
the
300
mV
range
the
unit
display
is
“mV”
against
“V”
on
the
300
V
range.
Diode
Check
3.000
(Fixed
range)
d.ddd
ann
E
ELLIN
3
30
300
3000
MAKING
MEASUREMENTS
DC/AC
Voltage
Measurements
Important:
The
maximum
input
limit
for
voltage
measurement
is
1000
V/DC
and
750
V/AC
(RMS).
If
you
attempt
to
measure
DC
voltages
above
1000
volts
AC
volts
above
750
volts
RMS,
your
unit
may
be
damaged.
All
the
figures
on
the
display
will
blink
when
more
than
the
maximum
rate
(DC
1000
V/AC
750
V)
is
supplied:
DISCONNECT
PROBES
IMMEDIATELY.
1.
Set
the
function
switch
to
DC
V
or
AC
V.
2.
Set
the
range
switch
as
required
for
the
voltage
level
to
be
measured.
If
you
do
not
know
the
voltage
level,
start
with
the
range
switch
set
to
the
highest
position
and
reduce
the
setting
as
required
to
obtain
a
satisfactory
reading.
18
Making
Measurements
3.
Plug
the
red
lead
into
the
+
jack
and
the
black
lead
p
the
—
COM
jack.
4.
Connect
the
probes
to
the
circuit
to
be
tested.
In
DCV,
the
minus
sign
will
appear
if
voltage
is
negative.
5.
Readthe
range
by
the
position
of
the
decimal
point.
IOA
O
750V
MAX
©
Black
Lead
Red
Lead
PARALLEL
CONNECTION
©
=
Red
Lead
+
Black
Lead
—
19
Making
Measurements
MAN
mV
3
30
300
3000
Notes:
1.
On
300
V
and
300
mV
ranges,
the
decimal
point
Willa
appear
in
the
same
position
(one
place
to
the
left),
but
if
the
300
mV
range
is
selected,
“mV”
will
appear
on
the
display.
2.
If
the
function
switch
is
rapidly
shifted
from
Kohm
to
DCV
with
the
range
switch
set
to
the
300
mV
position,
the
display
might
show
the
over-range
indication
because
of
the
high
input
impedance.
Short
the
test
leads
to
remove
this
condition.
3.
When
measuring
DCV
or
ACV
with
no
circuit
under
test
the
display
may
show
small
changes
in
the
lower
ranges.
This
is
normal.
A
high
input
impedance
produces
this
“wandering”
effect.
As
soon
as
a
circuit
is
connected,
normal
accurate
measurement
is
performed.
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