Keithley 5 digit digital multimeter dmm keithley 6485 e p the keithley 6485 is a 5 frac12 digit digital multimeter dmm that combines current measurement instrumentation with enhanced speed and a robust design p p the 6485 has eight current measurement ranges and high speed autoranging this cost effective instrument can measure currents from 20fa to 20ma taking measurements at speeds up to 1000 readings per second p p the multimeter has a 10fa resolution and superior sensitivit