This application note explores the use of an electronic load (eLOAD1) as a series modulation element to provide fast transient 200A current pulses from a 400VDC SMPS source. In essence, the eLOAD becomes an external linear post regulator that can be sized and optimized for the type of device to be tested. The eLOAD also conveniently provides a built-in transient modulator, greatly facilitating appropriate test signal generation. The test setup and results are presented in this paper, along with observations and considerations when specifying equipment for conducting similar testing.