IPC-TM-650 EN 2022 试验方法.pdf - 第422页

1 Scope The purpose of this test is to measure the capaci- tance effects arising from plastic substrates, adhesives, or coatings, which may be critical to the reliable functioning of a circuit. 2 Applicable Documents Non…

rest

on the test specimen.

5.3.2

The

arc tester should be set up for operation in the

automatic mode.

5.3.3

Set

the Variac to the voltage which produces 12,500

volts based on the last calibration of the Instrument (generally

105V to 115V).

5.3.4

Reset

the timer on the tester to ‘‘0’’ seconds if

required.

5.4

Test Procedure

5.4.1

Remove

a preconditioned specimen from the ambient

temperature distilled water and wipe dry with a lint free paper

towel.

5,4.2

Place

a specimen (individual or built up) in the elec-

trode fixture.

5.4.3

Operate

the tester in accordance with the manufactur-

er’s instructions such that an arc is generated and automati-

cally switched as indicated below.

ime (sec) On/Off Time Amperage

0-60 0.25 sec/1.75 sec 10 milliamps

60-120 0.25 sec/0.75 sec 10 milliamps

120-180 0.25 sec/0.25 sec 10 milliamps

180 continuous 10 milliamps

5.4.4

Observe

the arc carefully and, at the point which the

arc disappears and tracking occurs, stop the timer and record

the time for the specimen to the nearest second.

5.4.5

Remove

the specimen, remove and clean the elec-

trodes thoroughly using a solvent and if necessary the crocus

cloth.

5.4.6

Replace

the electrode and check the electrode gap.

5.4.7

Reset

the timer and proceed as in 5.4.1 through 5.4.6.

5.5

Calculation

5.5.1

Average

the values of the specimens tested from the

same sample and round to the nearest second.

5.6

Report

5.6.1

Report

the average value of the arc resistance in sec-

onds.

5.6.2 Report

the ambient temperature and relative humidity

at the time of the test.

5.6.3

Report

how the specimen was prepared, e.g. indi-

vidual, # of plies built up, or with a spacer.

5.6.4

Report

the preconditioning procedure.

5.6.5

Report

any anomalies in the test or variations from

procedures or tolerances specified.

6.0 Note

6.1

The

results of arc tests may be significantly affected by

contamination of the electrodes. Any irregularity of the arc in

the early portion of the test may be an indication of contami-

nation. If this occurs, the test should be stopped, the elec-

trodes cleaned and a fresh specimen should be tested (or the

test may be run in a different area of the same specimen).

6.2

While

values for reinforced material may vary with the

grain direction of reinforcement, the effect is generally insignifi-

cant with glass reinforced product. At least one specimen in

both machine and transverse direction is recommended to

verify this.

IPC-TM-650

Number

2.5.1

Subject

Arc

Resistance of Printed Wiring Material

Date

5/86

Revision

age2of2

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Scope

The

purpose of this test is to measure the capaci-

tance effects arising from plastic substrates, adhesives, or

coatings, which may be critical to the reliable functioning of a

circuit.

Applicable Documents

None

Test Specimen

Specimen

thickness for all tests must be

uniform within ±1% of the average thickness. At frequencies

below 1 MHz the specimen shall be large enough to provide

circular electrodes at least 10 cm in diameter and between

1.5 mm to 6.35 mm thick. At frequencies from 1.0 MHz to

1000 MHz, a micrometer electrode holder should be used

with the test specimen.

Equipment/Apparatus

4.1

bridge or resonant circuit capable of measuring the

capacitance and dissipation factor with the required accuracy

at the specified frequency may be used. The inherent accu-

racy of the measurement shall be ± 0.5%, ± 0.2% picofarad,

unless otherwise specified. The electrode material may be thin

foil, evaporated metal, sprayed metal, or air drying conductive

paint.

4.2

The

generating circuit may be any suitable source that

can furnish sufficient current for the specified precision of

measurement or voltage gradient in the dielectric.

Procedure

5.1 Preparation

The

atmospheric conditions surrounding

the specimen prior to and during test must be 23°C, ± 1.1°C

and 50%, ± 4% RH.

5.2

Test

Place

the test specimen in a suitable measuring

cell or holder and measure its capacitance and dissipation

factor with a suitable measuring circuit having required sensi-

tivity and accuracy.

5.3

Evaluation

Record

the shape and dimensions of the

specimen, type and dimensions of electrodes and measuring

cell, test conditions, method of measurement, applied voltage,

voltage gradient, and frequency and capacitance.

5.4

Calculation

C =

4πdo

where:

= capacitance in Farads

Q = total charge in coulombs

V = potential difference between plates in volts

GA = area of plates

4πdo = distance between plates

6 Notes

6.1

Suitable

measurement techniques must be used to mini-

mize errors due to the connections between the measuring

apparatus and the specimen.

6.2

The

AC voltage actually impressed across the specimen

must be as low as possible. When DC polarizing voltages are

required, it must be as specified.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.2

Subject

Capacitance

of Insulting Materials

Date

7/75

Revision

Originating Task Group

N/A

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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1.0

Scope

determine if the plated through-holes are suf-

ficiently plated to withstand a relatively high current potential.

2.0

Applicable Documents

None

3.0

Test Specimen

Any

plated through-holes on a test

coupon or finished printed wiring boards.

4.0

Apparatus

Power

supply capable of generating 10

amps and having a suitable load resistor.

5.0

Procedure

5.1 Test

Select

a load resistor, such that when the resistor

shunts the positive and ground terminals at a regulated

amperes power supply, a current of 10 amps will flow through

each plated through-hole in the circuit in series with the resis-

tor, for 30 seconds.

5.2

Evaluation

Examine

for breakdown (opens) when the

current is applied to each plated through-hole.

6.0 Notes

The

power supply unit should have a safety

interlock mechanism because of the relatively high current

required for this test.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.3

Subject

Current

Breakdown, Plated Through-Holes

Date

8/97

Revision

Originating Task Group

N/A

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.

age1of1

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ