Electromagnetic pulses (EMP) can be delivered to electronic equipment in two ways: Through the application of radiated fields, and through conduction along cables and wires. In this study, a high-voltage pulse generator using a spiral Blumlein Pulse Forming Line (PFL) was developed to test EMP effects by radiation and conduction. For the conduction test, a spiral strip Blumlein PFL with transformer oil was employed to generate high voltage (>300kV) and long duration (50∼ ns) pulses. High power ultrawide band pulses for the radiation test were generated by combining a TEM horn antenna with the high voltage generator. The peak-to-peak value of electric field intensity of a radiated pulse was approximately 53kV/m at a distance of 10m away from the antenna. The pulse generation system will be used for the examination of effects of the electric fields and conducted pulses on the operation of electronic devices.