The purpose Immunity testing of a electrical equipment is to evaluate its resistance to external electromagnetic interference (EMI).
Immunity is categorized as
- Electrostatic Discharge (ESD)
- High spike of voltage wave form generated by external source such as a human finger conducted through either spark in the air or physical contact
- Radiated Immunity (RI)
- Electromagnetic interference generated by external source such as a hobbyist ham radio picked up by the radio antenna on the electrical equipment
- Conducted Immunity (CI)
- Noisy voltage waveform generated by external source such as an external power supply picked up by the power cable to the electrical equipment.
Summary & Conclusion
- Electronic product level of resistance towards electrostatic discharge (i.e body or machine static discharge) is tested against ESD standards.
- Electronic product level of resistance towards radiated interference is tested against RI standards
- Electronic product level of resistance towards conducted interference is tested against CI standards
Immunity of an electronic product in the every increasing electromagnetic noisy environment is essential for product reliability.