Electromagnetic Compatibility (EMC)

Question 1

!!! Describe electromagnetic compatibility

Answer 1

The ability of a system or equipment to function satisfactory in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment.

Question 2

What is immunity vs emissions?

Answer 2

Emissions is the energy that your device spews out.

Immunity is your devices ability to withstand external energy.

Question 3

what is immunity vs susceptibility?

Answer 3

Immunity - degree to which a device RESISTS external energy

Susceptibility - degree to which a device is MESSED UP by external energy

Question 4

What are the key components of source/path/receptor model?

Answer 4

1) Source
2) Receptor
3) Path
4) Radiative coupling
5) Conductive coupling
6) Emissions
7) Immunity/Susceptibility

Question 5

What is intentional vs unintentional radiators?

Answer 5

Intentional – things that are SUPPOSED TO RADIATE energy

Unintentional – things that are NOT SUPPOSED TO RADIATE but do as a side-effect

Question 6

What is unintended radiation?

Answer 6

Electromagnetic Pollution

Question 7

What is inductive / capacitive, the source or receptor?

Answer 7

source –> inductive

receptor –> capacitive

Question 8

What are the 4 types of TRANSFORMING PATHS

Answer 8

1) Conducted
2) Radiated
3) Conducted(then radiating from cable)
4) Radiated (then picked up by cable and conducted)

Question 9

What emc compliance standards do these countries adhere to? US, Canada, EU, Japan, Australia/New Zealand

Answer 9

US - Federal Communications Commission (FCC)
Canada - Standards from Industry Canada (IC)
EU - Declaration of Conformity (CISPR)
Japan - need VCCI marking
AU/NZ - ACA registration

Question 10

What is a class A vs class B device

Answer 10

Class A - marketed for use in commercial, industrial or business environments
Class B - marketed for use in residential environments

Question 11

What is FCC?

Answer 11

US Federal Communications Commission

Question 12

What is IC?

Answer 12

Industry Canada

Question 13

What is IEC?

Answer 13

International Electrotechnical Comission

Question 14

What is CISPR and what is it’s function?

Answer 14

Comité International Spécial des Perturbations Radioélectriques.

It’s the analog standard for EU.

Question 15

What is ITE?

Answer 15

Information Technology Equipment

Question 16

What is DUT?

Answer 16

Device under test

Question 17

What is EUT?

Answer 17

Equipment under test

Question 18

What is OATS?

Answer 18

Open Area Test Site

Question 19

What is insertion loss? What are the 3 major types?

Answer 19

The lost of signal power when a device is introduced into the transmission line. Measured in decibels.

1) Reflected losses
2) Dialectic losses
3) Copper losses

Question 20

What is the configuration of a series resonant circuit?

Answer 20

A resistor, capacitor, and inductor in series.

Question 21

What is the configuration of a parallel resonant circuit?

Answer 21

A resistor, capacitor, and inductor in parallel.

Question 22

What is parasitic capacitance?

Answer 22

Typically unwanted capacitance between parts of an electronic component or circuit due to their proximity to each other.

At low frequencies, it can typically be ignored, but at higher frequencies, it can cause major problems.

Question 23

What documentation do you have to provide in order to get EMC approved?

Answer 23

1) frequencies of all oscillators and crystals
2) schematics and pcb layouts
3) connection diagrams
4) operating modes
5) product configurations
6) power supply data