Filters and Surge Protectors — Lesson 6

This lesson covers the solutions to Electromagnetic Compatibility (EMC) problems, focusing on surge protection components and filters. It provides a detailed explanation of gas discharge tubes, varistors, diodes, and filters. The lesson also discusses the characteristics of a surge and how devices can be protected against surge currents. It further explores the high-frequency behavior of components and the non-linear characteristics of metal oxide varistors and spark gaps. The lesson concludes with an examination of the V-I characteristics of gas discharge tubes and metal oxide varistors, and the use of filters for surge protection.

Video Highlights

00:13 - Introduction and surge protection components
02:48 - Characteristics of a surge protectors
08:31 - V-I characteristics of gas discharge tubes
12:46 - V-I curve of a metal oxide and zinc-oxide varistors
16:14 - Cascade protection and the use of several stages for protection
18:16 - Explanation of filters
20:27 - Power supply filters for protection against both common mode and differential mode electromagnetic noise

Key Takeaways

- Devices can be protected against surge currents by blocking or limiting the surge currents or by diverting the surge currents.
- Metal oxide varistors and spark gaps are non-linear devices whose characteristics are affected by the amplitude of the surge.
- Gas discharge tubes and metal oxide varistors have different operating characteristics and response times.
- Filters, which can be a combination of series or shunt devices, can be used to attenuate any leftover low-level but very fast noise from the last stages of protection.
- Cascade protection often uses several stages for protection, reducing the transient from the previous stage.