10fA resolution 5-1/2 digit resolution <200μV burden voltage Alternating Voltage method ohms measurements Automated voltage sweeps for I-V characterization Floating measurements up to 500V Up to 1000 readings/second Built-in Model 486 and 487 emulation mode IEEE-488 and RS-232 interfaces Analog output Digital I/O The 5-1/2 digit Keithley 6487 Picoammeter/Voltage Source improves on the measurement capability of the award-winning Model 6485, and adds a high resolution 500V source. It provides higher accuracy and faster rise times than the 6485, as well as a damping function for use with capacitive devices. With eight current measurement ranges and high speed autoranging, this cost-effective instrument can measure currents from 20fA to 20mA, take measurements at speeds up to 1000 readings per second, and source voltage from 200μV to 505V.