EMC Glossary
A plain-English guide to the standards, accreditations, test types and facilities you'll see across listings on this directory - useful whether you're sourcing a lab for the first time or double-checking what a test report actually covers.
General terms
| Term | What it means |
|---|---|
| EMC (Electromagnetic Compatibility) | A product's ability to work properly in its electromagnetic environment without causing unacceptable interference to anything else. |
| EMI (Electromagnetic Interference) | Unwanted electromagnetic energy that disturbs how a device works, or that a device gives off and disturbs others. |
| Emissions | The electromagnetic energy a product gives off. Emissions tests check it stays below the limits in the relevant standard. |
| Immunity | A product's ability to keep working correctly when exposed to electromagnetic disturbances. Immunity tests apply a disturbance and check the product's behaviour. |
| Full compliance testing | Formal testing to a defined standard, usually in an accredited lab, producing a test report that can support a declaration of conformity. |
| Pre-compliance testing | Early, indicative testing during development, used to find problems before formal testing. It does not replace a formal test report. |
| EUT (Equipment Under Test) | The product being tested. Also called the DUT (Device Under Test). |
| Test report | The lab's record of what was tested, how and what the results were. Buyers and regulators ask for it as evidence of compliance. |
| Technical file | The documentation a manufacturer keeps to show a product meets the requirements for CE or UKCA marking, including its EMC test evidence. |
| Declaration of Conformity | The manufacturer's own signed statement that a product meets the requirements that apply to it. |
Standards & Regulations
| Term | What it means |
|---|---|
| CE (EMC Directive) | EU Directive 2014/30/EU covering electromagnetic compatibility. A product carrying the CE mark for EMC has been assessed against harmonised EN standards for emissions and immunity. |
| UKCA | UK Conformity Assessed marking, the UK's post-Brexit equivalent to CE for goods placed on the Great Britain market. |
| FCC (US) | Federal Communications Commission requirements, commonly FCC Part 15, governing electromagnetic emissions from electronic devices sold in the United States. |
| ISED (Canada) | Innovation, Science and Economic Development Canada, the Canadian regulator for radio and EMC compliance. |
| VCCI (Japan) | Voluntary Control Council for Interference, Japan's EMC compliance scheme for information technology equipment. |
| MIC (Japan) | Ministry of Internal Affairs and Communications, Japan's regulator for radio equipment certification. |
| ACMA (Australia/NZ) | Australian Communications and Media Authority, which administers the RCM compliance mark covering EMC and radio equipment for Australia and New Zealand. |
| RED (Radio Equipment Directive) | EU Directive 2014/53/EU covering radio equipment, including EMC, radio spectrum use and, for some products, cybersecurity requirements. |
| MIL-STD-461 | US Department of Defense standard for the electromagnetic interference and compatibility characteristics of military and defence electronics. |
| RTCA DO-160 | The standard environmental and EMC test procedure for airborne equipment, used across civil and military aerospace. |
| CISPR 25 (Automotive) | International standard for the radio disturbance characteristics of automotive components and vehicles, protecting on-board radio reception. |
| ISO 11452 | International standard series for testing a vehicle component's immunity to electromagnetic radiation. |
| ISO 7637 | International standard covering electrical transient disturbances conducted along a vehicle's supply lines. |
| NATO AECTP-500 | NATO's Allied Environmental Conditions and Test Publication covering electromagnetic environmental effects for military equipment. |
| DEF STAN 59-411 | UK Ministry of Defence standard for the EMC of defence equipment, the UK's equivalent to MIL-STD-461. |
| SDIP-27/2 (NATO TEMPEST) | A NATO standard for TEMPEST testing, covering the electromagnetic emissions security of sensitive equipment. |
| EUROCAE ED-107A / SAE ARP5583A (HIRF) | The aerospace industry's guidance standards for High Intensity Radiated Fields (HIRF) testing and certification. |
| UN Regulation 10 (Vehicle EMC Type Approval) | The UNECE regulation covering EMC type approval for vehicles, commonly referred to as "E-marking". |
| EN 50121 (Railway EMC) | The European standard series covering EMC requirements for railway applications, from rolling stock to trackside equipment. |
| ISO 10605 (Automotive ESD) | International standard for testing a vehicle's immunity to electrostatic discharge. |
| ISO 16750 (Automotive Environmental) | International standard covering environmental conditions and testing for electrical and electronic equipment in road vehicles. |
| VSTD 56-4 (Taiwan Automotive EMC) | Taiwan's vehicle EMC standard, required for automotive type approval in the Taiwanese market. |
| SPE-J-000-E-1000 (Eurofighter Typhoon EMC) | A platform-specific EMC specification for equipment fitted to the Eurofighter Typhoon aircraft. |
Accreditations
| Term | What it means |
|---|---|
| UKAS | The United Kingdom Accreditation Service, the UK's national body for accrediting test and calibration laboratories. |
| ISO/IEC 17025 | The international standard specifying the general requirements for the competence of testing and calibration laboratories. Most UKAS-accredited EMC labs are accredited specifically against this standard. |
| ISO/IEC 17065 | The international standard for bodies certifying products, processes and services, relevant to labs that also carry out formal product certification. |
| A2LA | The American Association for Laboratory Accreditation, a US accreditation body equivalent to UKAS. |
| Notified Body | A UK or EU-designated organisation authorised to assess conformity for products requiring third-party certification, such as CE marking under certain directives. |
| UK Approved Body | The UK's equivalent designation to a Notified Body, authorised to assess conformity for UKCA marking. |
| TEMPEST (CPTAS) | The Platform TEMPEST Accreditation Scheme, the UK's NCSC-run scheme for testing platform-level (vehicle, vessel, aircraft) TEMPEST emissions security. |
| TEMPEST (CFTCS) | The Formal TEMPEST Certification Scheme, the UK's NCSC-run scheme for certifying TEMPEST-secure IT products and equipment. |
Test Types
| Term | What it means |
|---|---|
| Radiated Emissions | Measures the electromagnetic energy a product unintentionally radiates into its surroundings. |
| Conducted Emissions | Measures electrical noise a product feeds back onto its power or signal cables. |
| Harmonics & Flicker | Assesses distortion a product introduces onto the mains supply, and any resulting visible flicker in lighting. |
| Radiated Immunity | Tests whether a product continues to operate correctly when exposed to an external electromagnetic field. |
| Conducted Immunity | Tests whether a product continues to operate correctly when RF disturbance is injected onto its cables. |
| ESD | Electrostatic discharge testing, assessing a product's resilience to static shocks from handling or its environment. |
| Surge | Tests a product's resilience to high-energy voltage spikes, such as those from lightning strikes or switching events. |
| Voltage Dips & Interruptions | Tests how a product responds to brief drops or interruptions in its mains power supply. |
| Transient/Burst | Tests resilience to fast, repetitive electrical transients, such as those from switching relays or contactors. |
| Magnetic Field Immunity | Tests whether a product continues to operate correctly in the presence of a steady or power-frequency magnetic field. |
| Bulk Current Injection (BCI) | A technique for testing cable immunity by injecting RF current directly onto a wiring harness, common in automotive and aerospace testing. |
| Pre-Compliance Scanning | Early-stage, indicative EMC testing carried out during development, ahead of full accredited compliance testing. |
Chamber & Facility Types
| Term | What it means |
|---|---|
| Fully Anechoic Chamber | A fully RF-shielded room lined with absorbing material on every surface, simulating free-space conditions for radiated testing. |
| Semi-Anechoic Chamber | An RF-shielded room with absorber on the walls and ceiling but a reflective floor, the standard configuration for most commercial EMC compliance testing. |
| Reverberation Chamber | A shielded chamber that uses field-stirring rather than absorbers to build up high, uniform field strengths, often used for radiated immunity testing to defence and aerospace standards. |
| TEM Cell | A Transverse Electromagnetic cell, a compact enclosed test fixture used for smaller devices where a full chamber isn't required. |
| Open Area Test Site (OATS) | An outdoor test site, free of nearby reflective structures, used for radiated emissions and antenna measurements. |
| Screened Room | A basic RF-shielded enclosure without anechoic lining, typically used for conducted testing or as a supporting facility alongside a chamber. |
Spotted a term that should be added, or something that reads unclearly? Let us know at emc@emcdirectory.co.uk.