This SAE Standard defines methods and apparatus to evaluate electronic devices for immunity to potential interference from conducted transients along battery feed or switched ignition inputs. Test apparatus specifications outlined in this procedure were developed for components installed in vehicles with 12-V systems (passenger cars and light trucks@ 12-V heavy-duty trucks@ and vehicles with 24-V systems). Presently@ it is not intended for use on other input/output (I/O) lines of the device under test (DUT). Measurement Philosophy Installed electrical equipment is powered from sources which contain@ in addition to the desired electrical voltage@ transients with peak values many times this value@ caused by the release of stored energy during the operation of a relay and/or other loads connected to the source while starting and/or turning off the vehicle. These tests are designed to determine the capability of equipment to withstand such transients. The tests are performed in the laboratory (bench tests). Bench test methods give results@ which also allow comparison between laboratories. These tests may not cover all types of transients@ which can occur in a vehicle. The test pulses described in Section 8 are@ however@ characteristic of typical pulses. To ensure proper operation of a vehicle in the electromagnetic environment@ vehicle testing should be performed in addition to bench testing.