RCA WV-38A Operating And Maintenance Instructions Manual

SUGGESTED

PRICE

5Q CENTS

operating and
maintenance instructions

RCA

Volt-Ohm-Milliammeter

Safety Precautions

For

proper operation, the ground (black) lead of the

should

be connected to the ground of the equipment under
any other connections are made. An important point to remember is
that

there

Therefore,

equipment under

is always danger inherent in testing electrical equipment.
the operator should thoroughly

test

before

working

on it, bearing in

familiarize

himself

mind

voltages may appear at unexpected points in defective equipment.

tional

precautions

which

experience in the industry has shown to be

important are listed below:

WV-38A

test,

before

with

that

the

high

Addi-

1. It is good practice to remove power before connecting

test

leads
to high-voltage points. If this is impractical, be especially careful to
avoid

ing

leads. Check

accidental contact

can

provide a ground.

on a properly insulated

2.

Filter

Therefore,

3.

Remember

tional
with

hazard of high voltages appearing at exposed points along the

them.

4.

To lessen the danger of accidental shock, disconnect

immediately

5. Remember

sible

hazards.

capacitors may store a charge large enough to be lethal.

discharge

that

test

leads for frayed or broken insulation before

after

test

that

Even

with

Working

equipment racks and other objects

with

floor

filter

capacitors before attaching

leads

with

is completed.

the

risk

a minor shock can place the operator in jeopardy of

more serious risks, such as a bad

one hand in your pocket and stand-

lessens the danger of shock.

test

leads.

broken insulation provide the addi-

working

test

of severe shock is

fall

or contact

only

with

one of the pos-

a source of higher

which

leads

voltage.

6. The experienced operator continuously guards against injury

and does not work on hazardous circuits unless another person is

avail-

able to assist in case of accident.

Trade

Mark(s)

Marca(s) Registrada(s)

® Registered

3/71

RCA

Volt-Ohm-Milliammeter

Description

The

RCA
all-purpose measuring instrument. The
AC

sine-wave voltages

volt

to 5000 volts; DC current

from

0.2 ohm to 20 megohms; and decibels

resistance is 20,000 ohms-per-volt on DC, and 5000 ohms-per-volt on AC.

Features of this versatile
resistors in all measuring circuits, and a large, easy-to-read meter
sensitive
two-color

positions.

of

the

50/zA

markings for

A

convenient function switch is provided

The +DC and

test
resistance ratio of electrolytic capacitors and many types of semi-conductor
devices.

Two

special
against burnout due to accidental overload.* A fuse protects the precision
multiplier

source.

in the ohms network.

The

WV-38A

Five
(4 penlight cells and 1
pounds, and measures 6% inches by 5^4 inches by
clips

are provided on the handle for carrying the

is

attractively styled,

WV-38A

Volt-Ohm-Milliammeter

WV-38A

from

0.1
from

volt

to 5000 volts; DC voltages

1 microampere to 10 amperes; resistance

from

test

instrument include the use of precision

is a completely portable,

will

measure rms values of

from

0.005

—20 db to +50 db. Input

with

movement. The panel has been specially designed

simplified

—DC

leads—a feature

silicon

diodes are used to protect the meter movement

that

operation.*

with

AC,

+DC, and —DC

positions of this switch reverse the polarity

is also

helpful

in checking the front-to-back

with

is completely portable, requiring no external power

internal batteries (not provided) are used for the ohms function

"D"-size

with

a rugged, lightweight, bakelite case.

flashlight

cell).

The unit weighs

SVs

inches. Convenient

test

leads. The

only

WV-38A

3V2

^Included

serial

on

numbers

1—Red Test

1—Slip-on

Boot

WG-297
WG-210

WG-211

WG-270A

Alligator

1—Warranty - Registration

High
Resistor 900

Resistor 495

Vinyl

wired

instruments

above

Lead

66,000

and Probe 1—Black Test

Clip

Available

Voltage Probe

V.

range)

V.

range)

Carrying

with

K.

Items

and Red

serial

Supplied

numbers

with

Clip

1—Instruction

(Batteries Not Supplied)

Accessories

Megohm

Megohm

for H.V. Probe (10 x

for

H.V.

for WV-38A

Probe (100 x

Case

above

WV38A

and

20,000,

Lead

Black

Book

multiplier

multiplier

and on

with

Boot

kits

with

Alligator

Card

for 5000

for 250

3

DC

Voltmeter

(at

full

RCA

Volt-Ohm-Milliammeter

Specifications

Electrical

scale) :

Ranges

0 to

.25,

1.0,

2.5, 10, 50, 250, 1000, 5000 volts
Input resistance 20,000 ohms-per-volt
Circuit
Accuracy

AC

Voltmeter

Ranges

loading

50

microamperes bleeder current

±3%

(at

full

scale) :

..

.."

.. .0 to

2.5,

10, 50,

250, 1000, 5000 volts
Input Resistance 5000 ohms-per-volt
Circuit

Accuracy

DC

Current

¥?o«Mo

Kanges••

Insertion

Accuracy

DC

Ohms:

R

X1 0-2000 12 ohms

R

X100 0-200,000 1200 ohms

R X 10,000 0-20,000,000 120,000 ohms
Accuracy

loading 200 microamperes bleeder current

±5%

Frequency

from

10 cps to 50 kc on the 2.5, 10, and 50

(at

1 0 to

Response (reference 1000 cps) flat

full

scale) :

' " " ^ 0 to 100

Loss

.0.25

within

volt

0

to

0

to

*4 db

ranges.

50 microamperes
1 milliampere
10 milliamperes

milliamperes

0

to

500 milliamperes

0

to

10

amperes

±3%

Ranges

Scale Ends Center Scale

120

Full

MA

Scale Currents

MA

±3° of

0.06

pointer position

MA

for

exact value

volt

Internal

AF

Output

Batteries:

RX1
R X 100

SizeD

Size D Cell,

R X 10,000

(at

Ranges

0 to

. .4

full

scale) :

Input Resistance 5000 ohms-per-volt
Circuit
Accuracy

Note

:

An

put

measurements

Loading

200

±5%

internally connected

in

4

Penlite

0.1

presence

Cells

*if DC

of DC

in

series

blocking

voltages.

Cell,

1%

volts

iy2 volts

with D cell,

7%

volts

2.5, 10, 50, 250 volts
microamperes

capacitor permits out-

RCA

Volt-Ohm-Milliammeter

Decibel

Dimensions—(less

used when measuring Ohms. The second black scale is used to read DC
voltages and currents. The two red scales are used when measuring AC
voltages, the lower one being used
scale on the meter is used for decibel measurements. A chart, located
at the lower right hand corner of the scale for convenience, is used when
making

Levels

2.5 V, range
10 V. range
50 V. range
250 V. range

(Zero

(May

DB is 1

be read on Output or AC positions)

Mechanical

handle)

Height

Width

Depth
Weight

There are

decibel measurements.

five

separate

milliwatt

in 600

ohms)

:

-20 to +10 DB

-

8to+22DB
+ 6to+36DB
+20 to +50 DB

Specifications

.

6% inches

. 5x/4

inches

:3Y$

inches

3l/2 pounds

Meter

scales on the meter. The top black scale is

Scales

only

for the 2.5 V. range. The bottom

Range

The

Range

12 positions. The Range

obtain

the function and range desired.

Switch,

located at the center of the control panel, has

Switch

Function

The

Function

has

three
switch
must be set to the "+DC" position.

9

The
"+" jacks, permitting direct measurement of negative direct current and
DC

voltage.
reversing
resistance ratio of electrolytic capacitors and many types of semiconductor
devices.

positions,

To

measure all AC Voltages and to make decibel measurements, the

must be set to the

For

positive direct current and DC voltage measurements, the switch

"—DC"

This

the polarity of the

Switch

"AC",

position reverses the polarity of the
switch position can also be used as a convenient means of

located at the upper left-hand corner of the panel

"+DC",

"AC"

position.

test

Switch

may be turned in either direction to

Switch

and

"—DC".

"—COMMON"

leads when checking the front-to-back

and

RCA

Volt-Ohm-Milliammeter

Operating

Zero

The pointer of the meter must indicate zero when the
the normal operating position. If the pointer
adjustment screw located at the lower center of the meter cover should

be readjusted.

Use of

The meter scales on the
ease

of operation and quick readability over a wide
ments. Scales have been grouped according to the type of measurement
for

which

the

WV-38A,

on

two
measurements, always use the
reading
Volts
the 50
50

Volt

obtained. This general rule applies to all AC and DC Voltage ranges.

For

resistance measurements, however, the

one

which

WV-38A

factor

plication

when

ment, the 0 to 10 scale is used, but the reading is

they are used.

Because of the wide number of measurement

it is often possible to take voltage or resistance readings

ranges

which

can be read from either the 50

Volt

range

provides the most accurate Ohms readings at mid-scale points.

For

some

with

is indicated by the setting of the

the

range

and scales. For

is

nearest

range

provides a reading

the scale to obtain the correct reading. The required

will

provide a reading

only should be used if a reading of

measurements

switch is set to the 1000 V. position for voltage measure-

Setting

Range

WV-38A

greatest

range

to the full-scale point. For example: 48 DC

nearest

it

will

Section

of

Pointer

does

and Meter

have been designed to provide

accuracy in voltage and current

which

Volt

or the 250

nearest

range

the center of the scale,

be necessary to use a

range

not indicate Zero, the

Scales

ranges

will

provide an on-scale

Volt

the full-scale point, the

best

selected should be the

switch. For example:

multiplied

WV-38A

range

of measure-

provided on

range. Because

accuracy is to be

because

multiplying

by 100 times.

is in

the

multi-

CAUTION:

When
to make a
ered necessary,
ment or impair the accuracy of indications.

It is also good practice for personal protection to turn off all power

to the circuit under

The power to the circuit under

resistance
may result.

6

making voltage or current measurements, it is good practice
trial

measurements

measurement at a higher

because

repeated overload may destroy the meter move-

test

when connecting or disconnecting the

are made, otherwise damage to the

range

test

must be turned off when

setting than is consid-

test

leads.

in-circuit

WV-38A