The Keithley Model 617 Programmable Electrometer is a highly sensitive instrument designed to measure voltage, current, charge, and resistance. Two forms of resistance measurements are included in the standard configuration: a constant current method, and a constant voltage method that uses a built in voltage source for greater sensitivity. The measuring range of the Model 617 is between 1OpV and 200V for voltage measurements, O.lfA and 2OmA in the current mode, O.ln and 200GO (up to 1OlQ using the built in voltage source), and lOfC and 20°C in the coulombs mode. The very high input impedance and extremely low input offset current allow accurate measurement in situations where many other instruments would have detrimental effects on the circuit being measured. A 4% digit display and standard IEEE-488 interface give the user easy access to instrument data. 1.2 FEATURES Some important Model 617 features include: 4½ Digit Display-An easy to read front panel LED display includes a 4½ digit mantissa plus a two-digit alpha or numeric exponent. Autoranging-Included for all functions and ranges. Digital Calibration-The instrument may be digitally calibrated from the front panel or over the IEEE-488 bus. l Zero Correct-A front panel zero correct control allows the user to cancel any offsets. Baseline Suppression-One button suppression of a baseline reading is available from the front panel or over the IEEE-488 bus. One-shot Triggering-A front panel control for triggering one-shot readings from the front panel is included. Isolated IOOV Voltage Source-A built in 1OOV scwrce is isolated from the electrometer section. The voltage source is programmable in 50mV steps. Selectable Guarding-A selectable driven cable guard is included to optimize speed. Standard IEEE-488 Interface-The interface allows full bus programmable operation of the Model 617. Analog Outputs-Both preamp and 2V full range analog outputs are included on the rear panel. 100~Point Data Store-An internal buffer that can store up to 100 readings is accessible from either the front panel or over the IEEE-488 bus. Minimum and maximum data points can be stored and are accessible from the front panel or over the IEEE-488 bus.