IPC-TM-650 EN 2022 试验方法.pdf - 第638页

IPC-2.5.33.3-1 Figure 1 Apparatus for Current Leakage Measurement MILLI- VOL T METER ELECTRODE (–) GROUND REFERENCE POINT 1.00 KOHM RESIST OR LEAKAGE CURRENT UNIT UNDER TEST (UUT) LOW FORW ARD-BIAS DIODES (HEADS-TO-T AIL…

4.5.4

Resistor,

1.00 KΩ, 1% (any commercially available

brand carbon or metal film)

4.5.5

Diodes (two) shall be of the lowest practicable known

forward bias devices. 1N34 diodes have been found satisfac-

tory for this purpose.

4.5.6

Receptacles (two)

4.5.7

Line

cord

4.5.8

Strain

relief

4.5.9

BNC

connector

4.5.10

Edge

Card Connector w/mounting hardware

4.5.11

Metal

(bud) box

4.6

Preparation of Apparatus

Connect

the apparatus as

illustrated in Figure 1. The diodes shall be wired head-to-tail to

be effective regardless of the applied signal’s polarity (± DC or

AC). The negative electrode of the apparatus must make

good electrical contact with the ground reference point. These

connections will be automatic when using the test box

detailed in Figure 2. Configure the UUT for typical operation.

In those UUT’s that utilize additional functions (such as pres-

sure or vacuum), provide switching actuation for these func-

tions.

Note:

The

plugs are in power receptacles during measure-

ments. They are shown unplugged here for clarity. Non-US

power receptacles may be different from those illustrated.

4.7

Calibration & Standardization

The

millivoltmeter shall

bear a current calibration sticker. If an oscilloscope is used,

the probe shall be adjusted to display the square wave cali-

bration signal generated by the oscilloscope without under-

shoot or overshoot.

Procedure

5.1 DC Measurement

Configure

the millivoltmeter for

measuring DC. Turn on the UUT and allow it to warm up to a

normal operating temperature. Touch the hot tip of the UUT to

the tinned area of the test electrode. Apply solder to form

good electrical contact. Let the tip dwell on the electrode

while the UUT cycles power to maintain temperature. Operate

various other functions of the UUT if present, such as the

vacuum pump or air solenoid by actuating the UUT’s finger

switch or foot switch. Wait for the reading to stabilize, then

record the reading.

5.2

AC Measurement

The

procedure for measuring AC is

the same as for DC except the millivoltmeter is configured for

AC.

5.3

Calculation and Interpretation of Results

Even

though

the meter reads out in millivolts, using 1.00 KΩ for the

resistor value results in the displayed numbers representing

the current in microamps without calculation (i.e., a readout of

0.8 mv indicates 0.8 µA).

The DC reading shall not exceed 1.0 µA. The AC reading shall

not exceed 1.0 µA.

6 Notes

tracking test results, record the measured values

on a copy of the form found in Method 2.5.33.

Testing has shown that for UUTs that utilize high frequency

circuits, layout and cord positioning can influence the AC cur-

rent leakage reading. A compact configuration such as the

one shown in Figure 2 minimizes those influences.

IPC-TM-650

Number

2.5.33.3

Subject

Measurement

of Electrical Overstress from Soldering Hand

Tools - Current Leakage Measurements

Date

11/98

Revision

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IPC-2.5.33.3-1

Figure

1 Apparatus for Current Leakage Measurement

MILLI-

VOLT

METER

ELECTRODE

(–)

GROUND

REFERENCE

POINT

1.00 KOHM

RESIST

LEAKAGE

CURRENT

UNIT UNDER

TEST (UUT)

LOW FORWARD-BIAS

DIODES (HEADS-TO-TAILS)

TEST

ELECTRODES

IPC-2.5.33-1

Figure

2 Current Leakage Test Circuit Conﬁguration (Cover Removed)

AC RECEPT

ACLE

FOR VOLTMETER

AC RECEPTACLE

FOR UUT

BNC CONNECTOR

FOR VOLTMETER

TEST ELECTRODE

CARD EDGE

CONNECTOR

1K RESISTOR

METAL BOX

DIODES

GRN

BLK

WHT

IPC-TM-650

Number

2.5.33.3

Subject

Measurement

of Electrical Overstress from Soldering Hand

Tools - Current Leakage Measurements

Date

11/98

Revision

age3of3

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Scope

The

following information is a supporting docu-

ment in support of Method 2.5.33. The test methods within

this group of procedures can be falsely influenced by radio

frequency interference and electromagnetic interference from

lighting and equipment found in the workplace and testing

area. To avoid these influences, the leakage and transient

tests should be performed in a screen room. In lieu of a

screen room, this test method has been provided to make a

low cost shielded enclosure, which should provide adequate

shielding for the performance of these test procedures.

Applicable Documents.

ANSI/J-STD-001

Requirements

for Soldered Electrical and

Electronic Assemblies.

Test Specimens

None

required

Equipment/Apparatus

Only

general guidelines are pro-

vided. The enclosure can be made from readily available

materials obtainable from any hardware store or lumber yard.

Dimensions may be adjusted up or down to accommodate

equipment to be tested. Experience has shown that best

results will be obtained with a full length piano hinge across

the back of the lid. The lid should be secured in the closed

position with a metal, cam-type locking mechanism. The

screening material from the lid should contact the material

covering the sides to ensure a complete seal.

In addition to information on the enclosure, Section 6 also

includes information on the filtered AC power module and test

electrode mounting that should be incorporated into the local

design to achieve best performance.

Procedure

construction procedure is provided. Each

local activity should construct the enclosure to meet their spe-

cific needs based on the information in Section 6.

6 Notes

6.1

Shielded Enclosure

High

measuring impedance is

used so as not to load down the signal being generated by

the UUT. Because a high measuring impedance is used,

there’s a threat that transients emanating from sources other

than the UUT might be displayed. To prevent the apparatus

from picking up ambient EMI/RFI, the UUT is placed inside a

‘‘benchtop’’ shielded enclosure. Filtered AC line voltage is

available from within.

Some construction suggestions are given in 6.2 and 6.3.

6.2

Basic Enclosure

Although

Figure 1 illustrates wire

mesh walls, sheet metal walls also work. Metals other than

copper or brass may be used. If mesh is used, it should be

6.5 mm or tighter weave. Whatever metallic materials are

used, continuity across seams and to the lid should be

ensured.

Figure 2 suggests a way for mounting to an AC power entry.

6.3

Test Electrode

The

test electrode (see Figure 3) is

shown mounted to the sidewall of the enclosure to facilitate

connection of test equipment to the UUT. Moving this struc-

ture entirely into shielded enclosure and providing an access

port through which test cables may be routed will slightly

increase the construction cost, but will also serve to better

isolate the test setup.

IPC-2.5.33.4-1

Figure

1 Enclosure Construction Suggestion

51 cm

81 cm

43 cm

LID

WOOD

SHEET

METAL

OR WIRE MESH

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.33.4

Subject

Measurement

of Electrical Overstress from

Soldering Hand Tools - Shielded Enclosure

Date

11/98

Revision

Originating Task Group

Manual Soldering Task Group (5-22c)

Material

in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.

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