Ch. 2 (Electromagnetic Compatibility) Flashcards Preview

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Flashcards in Ch. 2 (Electromagnetic Compatibility) Deck (37)
0

Visible light

10 to the 15th power

1

Conducted coupling

Except solid state

2

Internal EMI sources

Power lines
Motors
Cell phones
Except "incandescent lighting" or "electrical power cables"

3

EMI sources (natural)

Atmospheric electricity
Cosmic radiation

4

Electrostatic discharge

Spark in the air

5

CRT

Cathode Ray Tube

6

What interferes with CRTs

RFI

7

Unwanted signals

CM - common mode
DM - differential mode

8

An example of common mode

Locking up a computer

9

Differential mode affects

Corrupting transmitted signals

10

Types of EMI

Except unbalanced DM fields

11

Coupling mutual capacitance/inductance

Except signal injector

12

Tunnel problems

Except unbalanced DM fields

13

Man-made EMI sources

Electrical power
Generator
Communications electronics

14

ESD =

Electrostatic Discharge

15

Types of ESD

Spark
Radiated
Contact

16

ESD immunity

Contact level 2 - 4 KV
Contact level 4 - 8 KV
Air level 2 - 4 KV

17

Less than 5KVA

No separation necessary

18

Separation requirements for fluorescent lamps

5.12"

19

Separation from power in grounded metal conduit

6"

20

Separation from unshielded power lines near grounded metal conduit

12"

21

Separation from unshielded power lines near open pathways

24"

22

Separation from electrical motors & transformers

47"

23

Mitigate unwanted signals w/ ___

Ferrite beads

24

Magnetic scheme

Filters unwanted signals

25

Two types of EMI

Man-made
Natural

26

How to measure EMC

There is no technique

27

EMC =

Electromagnetic Compatibility

28

Separation for arc welders

31.5"

29

Electromagnetic fields are ___ undesirable

Not always

30

___ are created when inductive and capacitive circuits are switched on and off

Electrical fast transient (EFT) disturbances

31

Inadequate gaskets/enclosures can be a source of ___

Radiated interference

32

RMS power

.707

33

Difference between two grounds should be no more than ___

1.00

34

Modern electronics are ___ susceptible to EMI

More

35

Instrumentation shield grounding

Grounding for longer shield runs

One end

Both ends

36

Minimum CM rejection ratio

40 dB