Picoammeter, 5 1/2 digit Resolution, 10fA, unit with IEEE and RS-232 Interfaces. The Keithley 6485 is a high resolution bus-programmable (RS-232 and IEEE-488) picoamperemeter. It combines sensitive current measurement instrumentation with enhanced speed and a robust design. Cost-effective low current measurement solution 8 Current measurement ranges from 20 fA to 20 mA (with 20 fA range having the lowest noise) High-speed autoranging Measurement speed: up to 1000 readings/s Resolution: 10 fA Burden voltage: < 200 uV Built-in model 485 emulation mode IEEE-488 and RS-232 interfaces Analog output