A Basic Guide To EMC

Electrical ‘noise’ from the toothbrush motor is being transmitted through the air in the same way that signals are transmitted to your TV. Wires and tracks within the shower radio act as tiny aerials and pick up this signal which appears as a crackling sound. To use the correct terminology, the toothbrush is sending ‘radiated emissions’ and the radio has poor ‘radiated immunity’.

Another example is when the washing machine launches into the final spin, wobbly lines may appear on the monitor of your PC. What is happening now?

This time, the electrical ‘noise’ is being conducted through the mains. Again the items are not electro-magnetically compatible, but this time the problems are ‘conducted emissions’ and ‘conducted immunity’.

Fortunately, such events are rare because the European Union insist that all electrical and electronic goods meet the Electro-Magnetic Compatibility or EMC standards, one of the many safety standards associated with CE marking. It can be perceived that these standards are an inconvenience, but there are some compelling reasons why electrical equipment needs to be compliant. For example, it would be unthinkable for a life-support machine in a hospital to fail because someone had selected ‘hot chocolate’ from the vending machine down the corridor.

Despite many of the rumours you may have heard, there is nothing mystical or magical about EMC. At Top Hex, our engineers come across EMC every day and we will work with you to ensure that your product is compliant.