Two parallel experiments have been undertaken to investigate the mechanisms which govern the recovery of spark gap switches in repetitive applications. Measurement of the neutral gas density is accomplished using a laser Schlieren technique which enables spatial and temporal cooling of the gas to be observed. The rate of rise of voltage recovery is recorded using a double-pulse modulator system which determines the breakdown voltage of the gas at specific time intervals after breakdown by the first pulse. A continuous sweep voltage is applied to the switch in order to establish the influence of ions on the recovery characteristics. Results are presented for SF₆/bin and air which show that voltage recovery is not solely governed by recovery of neutral gas density. There is a significant influence from the residual ion population created by the previous discharge. This influence is dominant for several hundred milliseconds after breakdown. The application of a suitable sweep voltage effectively minimizes the ion population, which results in significantly improved voltage recovery characteristics.