The Model 617 Programmable Electrometer is our latest and most advanced electrometer. It is a sensitive, versatile, 41/2-digit, 7-function instrument which includes a bipolar 100V voltage source, a decade current source, IEEE-488 interface, and outstanding low current accuracy specifications. It has better specifications, superior capabilities, and is essentially the same price as our Model 616, which has been the standard sensitive dc meter in most scientific and engineering laboratories for the last 10 years. The 617 can measure resistances or generate I-V curves using either of two measurement techniques. Using the 1nA to 100µA decade current source, a known constant current is forced through the unknown resistance. The developed voltage is measured with a high input impedance voltmeter, and the resistance or voltage is displayed and transmitted over the IEEE bus. Alternatively, the 617's programmable voltage source is applied across the unknown and the resulting current is detected by the 617's sensitive current circuitry (see Figure 13 on page 47). Current may be displayed directly, or resistances as high as 101612 can be directly measured; the 617 can calculate and display the quantity V/I. Since the resistance of most high resistance materials is a function of the applied voltage, the controlled voltage technique provides better characterization of these materials. The 617's built-in IEEE-488 interface makes all controls programmable. You get full autoranging over the full span of ranges on voltage, current, charge, or resistance functions. And you can choose your format for the front panel readout: either exponential or engineering units. The JFET input gives you lower voltage noise and more immunity to overload, without sacrificing current sensitivity. Pushbutton suppression lets you make relative measurements with respect to a selected baseline, or cancel background signals. Zero Correct cancels internal offsets with the touch of a button. Both are bus controllable. The built-in V-© Guard switch lets you drive the inner shield of the triaxial input cable at guard voltage, minimizing leakage current and time constants. 100-point Data Storage is also built-in, with Min/Max readings available from front panel or bus. For all its precision and performance, the 617 is extremely easy to operate. Its DMM-like controls and clear 41/2-digit display let you handle a variety of applications quickly and easily. And, like a DMM, the 617 features simple Digital Calibration. It also has real-time input and output triggers for communication with other instrumentation.