We report on the electrical and electromagnetic characterization of a solid-state driven capillary plasma source developed for plasma-based accelerators applications. The system utilizes a high-voltage pulsed discharge to generate plasma channels within gas-filled capillaries, where the discharge is initiated by a high-speed silicon controlled rectifier-based switching circuit. This work details the interplay between the circuit’s pulsed-power dynamics and the resulting electromagnetic environment. Through a characterization campaign using fast Fourier transform analysis, we investigate the transient electric and magnetic fields generated during the ionization process. We identify inductive coupling as the primary source of electromagnetic interference affecting sensitive control instrumentation. Finally, we demonstrate the implementation of effective mitigation strategies—including optimized grounding topologies and cable geometry—that ensure stable operation and high shot-to-shot reproducibility of the plasma source.