Lightning transient suppression circuit design for avionics equipment

Aircraft manufacturers are increasingly choosing to use Carbon Composite material for the design of their airframes due to its obvious advantage of reducing the weight of the aircraft. However, a disadvantage of this decision is the large increase in the lightning indirect effect levels to which avionics equipment are exposed. The typical method of protecting avionic interfaces from these transients is to clamp the transient using a suppression device such as: metal oxide varistors (MOV), transient voltage suppressors (TVS), or gas discharge tubes (GDT). Higher transient levels typically results in larger components, but aircraft manufacturers demand that the avionics equipment does not increase in physical size. This presents a major challenge to avionics manufacturers. This paper presents some techniques used to meet this challenge.