Keithley 485
The Keithley 485 Picoamperemeter is a dedicated picoamperemeter from the mid-1980s, from the same generation and model series as the better-known Keithley 197 "Microvolt DMM".
The 485 operates as a feedback (transimpedance) amperemeter (i.e. the input burden is constantly low at less than 0.2 mV), has a resolution of 4½ digits (19999), some rudimentary built-in logging capabilities, as well as an optional GPIB interface.
This instrument measures only (low) currents, in seven decadic ranges from 2 nA to 2 mA full scale. In the 2 nA ranget The least significant digit resolves 100 fA (0.1 pA).
Key Specifications
| Current | 7 decade ranges, 2 nA to 2 mA full scale |
|---|---|
| Display | 4½ digits, LED |