INTRODUCTION The Keithley Model 602 Electrometer is a completely solid-state, battery operated instrument, which measures a wide range of DC voltage, current, resistance and charge. The Model 602's input resistance of greater than 1014£] is the result of extensive instrument development with high input impedance transistors. The Model 602 has all the capabilities of conventional VTVMs, but can also make more measurements without loading circuits. The Model 602 has nine voltage ranges from 0.001 V full scale to 10V, 28 current ranges from 10⁻¹⁴A full scale to 0.3A, 23 linear resistance ranges from 100Ω full scale to 10¹³Ω, and 15 charge ranges from 10⁻¹³C full scale to 10⁻⁶C. The Model 602 offers complete line isolation and excellent off-ground measuring capability. Up to 1500V may be applied between the input low terminal and the case, and stage operation is assured with the case grounded. A triaxial connector allows complete guarding of the high impedance input terminal. The Model 602 employs matched insulated-gate field-effect transistors followed by transistor differential amplifier stages and a complimentary-output stage. A large amount of negative feedback is used for stability and accuracy. MODEL 602 FEATURES 1. The Model 602 has excellent zero stability which permits accurate measurements with minimal adjustment. Short term zero drift is less than 50µV per hour. Zero offset due to temperature change is less than 150µV per °C after 30 minute warm-up period. This offset, however, can easily be compensated for with the front panel zero controls. 2. Fast warm-up is an inherent characteristic of the Model 602. It can be operated 30 minutes after warm-up on the most sensitive range and almost immediately on less sensitive ranges. 3. Low offset current 5 X 10⁻¹⁵A, minimizes zero offset with high source resistance and permits maximum resolution when measuring current and charge. 4. The 1000 hour life of the batteries enables usage in long term experiments without interruptions for recharging. Battery life is maintained even when the 10mA recorder output is used. For further convenience, battery condition is readily checked on the panel meter. 5. Excellent overload protection without degradation of performance is obtained by use of a unique input circuit. The Model 602 Electrometer will withstand damage and has good recovery.