Mitigation of Lightning Transient Effects on Primary and Auxiliary Test Equipment Using Transient and Power Blocking Devices

RTCA DO-160, Section 22, outlines standardized test procedures and levels for assessing the susceptibility of avionics and aircraft equipment to the indirect effects of lightning. This section defines various waveforms designed to simulate lightning's indirect effects with specialized pulse generators required to generate these waveforms. During pin injection tests specific protection circuits are necessary to block unwanted signals from the Equipment Under Test (EUT) and power supply from damaging the pulse generator while ensuring that the applied pulses remain unchanged. This paper provides a comprehensive review of pin injection test methodologies using different types of test equipment, and introduces alternative transient and power-blocking devices for Waveform 4 and Waveform5 (WF4 and WF5). These devices protect primary and auxiliary laboratory equipment by directing most of the transient energy to the target pin, while blocking surges from reaching the power supply and other loads during direct pin injection tests.