让EMC原则变得简单

史提夫·希耶斯EMC公司Expert
By Engaged Expert 史提夫·希耶斯

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电磁兼容性(EMC公司)它经常被描述为“黑色艺术”,但解开它的关键是要理解它的基本原理。一旦学会了这些,EMC会突然变得简单得多。

在设计产品时,无论是物理产品还是系统,都必须询问需要考虑哪些因素才能确保实现EMC。为了做到这一点,有必要退一步回到基本问题,并考虑EMC干扰实际上是如何产生的。

用最简单的术语来说,干扰是由从一种能量状态转移到另一种能量状态引起的。就像轻按电灯开关一样,我们期望这种能量的传递是瞬时的。EMC法规,从商业的医学的军事的,基本上都是问如何停止沃尔特ge overshoot or undershoot which takes place during this transfer of energy so that a product can function without interference.

Ask the right questions

必须确定这种干扰的可能性。无论产生多少电磁噪声,都必须记住,必须有人或某物接收到该噪声才能发生干扰。必须提出的关键问题是:

  • 这个产品将在哪里使用?
  • 它将干扰什么/谁?
  • 能量如何从产品传递到“受害者”

能量将沿着电缆或通过空气传播,因此这两种机制是辐射和传导。这就是为什么使用的标准是基于辐射和传导测试。

还有其他机制需要注意,如电容耦合和感应。这些情况更不寻常,尽管随着新技术(如电动汽车和电器的无线充电)的不断出现和越来越广泛地采用,感应的重要性预计会增加,但它们造成的潜在干扰是有限的。

Take three key factors into account

无论是产品、系统还是印刷电路板,基本的EMC原则都是一样的。在考虑产品设计如何确保更大的电磁兼容性时,需要考虑三个关键因素:

  1. 屏蔽
  2. 接地
  3. 过滤。

When reviewing the shielding we think of metal boxes or shielded cables – things that provide a Faraday Cage. It is essential to make provision for 360° of complete continuity of the Faraday Cage – from good conductivity of the product's housing to its lid or termination of cables. Once sufficient shielding has been achieved, more energy will inevitably be pushed out via the cabling so appropriate filtering must now be considered. Finally, earthing, or how the energy will travel from a high potential to the earth/ground, must be factored into the equation.

元素经常看到产品失败是因为没有充分考虑这三个因素中的一个或多个。正是因为这个原因,我们现在提供Early Stage Qualification (ESQ®)service to support manufacturers through the complex nature of qualification testing and to allow for a smoother approvals旅程。ESQ本质上是确保屏蔽、滤波和接地在设计过程的早期考虑,而不是在故障更可能发生时在测试点考虑。我们一次又一次地看到,前端的早期投资如何使制造商在达到测试阶段时能够节省大量资金。

在开发周期的早期确认原型设计

最具成本效益的产品开发方法将始终是在开发周期的早期确认原型设计。一个关键的目标应该是在测试、批准和认证阶段第一时间取得成功。如果一个产品必须重新设计,那么它的价格可能会高得让人望而却步,从而导致推迟上市和消费者信心的丧失。yabo官网入口

在设计过程的早期考虑产品可能出口到哪里

而许多国家采用的法规几乎与CE标记, once a product is to be exported it becomes much more likely that mandatory third party testing will also be required. It is therefore vital to consider产品出口地在设计过程中尽可能早地提出建议。为满足不可预见的出口需求而对产品进行后期修改是一项成本高昂且耗时的工作,这是一个常见的错误。

CE标记has now been a legal requirement for over twenty years yet thousands of products still fail every year. Test houses such as Element will continuously be asked to provide guidance and advice on EMC compliance, be it at the beginning or the end of the design process. However, early advice to prevent issues arising later will always be the safer and more cost effective option.

For more information on ESQ and EMC compliance, pleasecontact us或致电英国+44 808 234 1667或美国+1 888 786 7555。

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