Simple and Accurate Estimation of the Parameters of a Fast Discharge Circuit

In many high-voltage pulsed-power experiments, a capacitor bank is discharged through a transmission line or coaxial cables into a load. To enable the discharge characteristics to be estimated, it is often necessary to determine the resistance and inductance of the supply system, and this is commonly achieved by discharging the capacitor with the load short circuited. Measurements made on the waveforms of the resulting current, or its on-time rate-of-change, then enable the required information to be calculated, although this can be quite a length and detailed process. However, this letter demonstrates that, by introducing approximations which are valid for rapid discharge circuits, it is possible to produce simple but accurate formulae for the unknown quantities which the authors have not found elsewhere in either pulsed-power handbooks' or circuit theory textbooks-", When a capacitance C charged to a voltage Vo is discharged into a series combination of resistance R and inductance L at time t = 0 the well-known result for the subsequent time variation of the current is