Electromagnetic Compatibility Description: Overview

Vehicles are typically subject to certain legal requirements that limit the amount of electromagnetic interference (EMI) that can be generated by the vehicles electronic devices. Additionally, the electronic devices within the vehicle must be able to withstand a certain amount of EMI without affecting their operation. EMI is generated whenever electrical current flows through a circuit. The amount of EMI generated or amplitude, is usually dependent upon the amount of current flow, amperage and the on-off pattern of current flow through the circuit, frequency. The EMI requirements are generally referred to as electromagnetic compatibility.

There are many ways of ensuring the vehicle meets electromagnetic compatibility requirements. These include:

• Adding capacitors and resistors to certain electrical circuits
• Regulating the frequency at which a component may operate
• Shielding the wires, cables and components