With an internal mains re-chargeable battery supply the Tinsley 5898 may be used "in the field" for periods of up to 8 hours without requiring recharging. A standard RS232 computer interface is included that may be used for printing resistance values or downloading measurements that have been stored in the instrument's memory. The Tinsley 5898 can be used fully auto-ranging or with manual range selection if required. Each of the 6 ranges has a choice of high or low measuring current with the exception of the lowest range, which is fixed at 200 Amps. Current can be selected to be positive or negative, with the option of automatic reversal to eliminate the effect of thermal E.M.F.'s.