Construction and measurement of an electromagnetic noise generator based on an automotive coil

Abstract

This article covers the design of an electromagnetic noise generator which uses an automotive coil as the main component. A short theoretical analysis covers the generation of high voltage pulsed current from the available DC source originated from the battery. An electronic dimmer, a circuit used to control the brightness of a light, by controlling the effective voltage that is delivered to the load, is used here to provide more degrees of freedom to the generated power as well as to insert higher order harmonics into the emitted electromagnetic spectrum. A prototype was built and its time domain current waveform is measured and shown, altogether with the measured radiated spectra, covering the frequency range from 20Hz to 1GHz. A broadband emission characteristics is verified, turning the use of common AM/FM radios impossible when close to the noise generator. A visible strong plasma is also seen due to the high generated voltages (around 60kV).

Keywords

• Applied Electromagnetism
• Electromagnetic Compatibility