EMC or we can say ‘Electromagnetic Compatibility’ is the strength of an electronic device to resist the interference if any by other electronic devices and to exist within an environment without causing any interference of itself.
EMC Testing can be divided into two main categories which are:
- Emission Testing: Electromagnetic disturbances caused by an electronic device can result in the interference or malfunctioning of another electronic device present in the same environment. This is referred to as ‘Electromagnetic Interference’ or EMI.
- Susceptibility or Immunity Testing: Immunity is said to be the ability of an electronic device to perform its functions normally in an electromagnetic environment without being affected by the emissions radiating from another electronic device. On the other hand, susceptibility is the opposite of immunity, in that the more a device is immune to EMI, the less susceptible it is.
EMC Emissions
Electromagnetic Compatibility Emission is further divided into 2 categories:
- Conducted Emissions
- Radiated Emissions
An electromagnetic field consists of following components:
- Magnetic Field or H-Field: Measured in amps per meter (A/m)
- Electric Field or E-Field: Measured in volts per meter (V/m)
Inspite of two separate fields, the components of the electromagnetic field are not a totally separate phenomena. Both H-Field and E-Field move at a 90º angle to each other.
Radiated Emissions in E-Field: These are the electromagnetic interference (EMI) or we can say the disturbances that stem from the frequencies generated within an electrical or electronic device. Radiated emissions result in challenging issues regarding compliance. These emissions disseminate through the air directly from the chassis of the device or from the interconnected cables. While EMC testing, measurements of radiated emissions are made using an EMI receiver or/and a spectrum analyzer and a measuring antenna.
Radiated Emissions in H-Field: The magnetic component of the electromagnetic wave is using an EMI receiver or/and a spectrum analyzer along with an appropriate measuring antenna. Typical magnetic field antennas include loop antennas and also include specific antennas according to CISPR 15 like the Van Veen Loop. The Van Veen Loop antenna is a three loop antennae built together for measuring a product’s magnetic field emissions in three axis i.e. X, Y and Z.
Conducted Emissions (Continuous and Discontinuous): The disturbances or EMI originating from frequencies generated internally by an electrical or electronic device are referred to as conducted emissions. These emissions then spread along the interconnected cables such as wired ports like power conductors or telecommunication ports. Conducted emissions can be either continuous i.e. continuously emit at a given frequency or discontinuous in nature i.e. non-constant and occurring sporadically. Under electromagnetic compatibility testing, measurements of conducted emissions are made on an EMI receiver through an ISN (impedance stabilization network) located inside the test chamber.
Click here to know about Immunity Testing as a part of EMC Testing.
ITC India is an NABL accredited testing laboratory providing EMC Testing Services along with many other testing services as per the client’s requirement. Contact b.vig@itcindia.org to get your TESTING QUOTE TODAY or visit our website https://itcindia.org/emc-emi-testing/ to know more about EMC Testing.
EMC Testing 