Electrostatic Voltmeter Model 320C eTectrostatic voltmeter NULL VOLTAGE The Trek Model 320C Electrostatic Voltmeter is a versatile instrument which is used for a variety of electrostatic applications including contact potential measurements, materials evaluation, and electret studies. The Model 320C makes highly accurate, noncontacting measurement of electrostatic potentials of 1 mV to 100 V over a wide range of probe-to-surface distances. The Model 320C is specifically designed for high sensitivity applications. The Model 320C has adjustments to compensate for many sensitive testing conditions. A calibrated Null Voltage supply of ±10 volts nulls contact potentials when measuring voltages on dissimilar materials. The Null Voltage source may be used to null different work function voltages of the test surface or to function as a zero suppression voltage source. A response Speed Control adjusts the speed/noise tradeoff of the Model 320C AC response. A self locking Drift/Spacing Null Adjustment minimizes the variation in monitored voltage values as the probe to test surface spacing changes. The front panel has an easy to read 3V2 digit LED display. The detected output voltage can be monitored through a 1:1 voltage monitor output and a switch selectable scale of 10:1 or 20:1 voltage monitor output. The Trek patented low impedance probe assures measurement accuracy which is essentially independent of probe-to-test-surface spacing while eliminating the external environmental effects of high humidity and contamination, such as airborne dust, toner, ions and chemicals, on measurement accuracy. • Measurement Range: 0 to ±100 V DC or peak AC • Sensitivity: 1 mV • Speed of Response: Less than 300 ms for a 100 V step • Measurement Accuracy: Better than 0.05% of full scale • Null Voltage Source: 10 volt nulling supply for contact potential measurements • Response Speed Control: AC response adjusted for speed/noise • Drift Spacing/Null Adjustment: Minimizes variations in voltage values as probe to test surface spacing changes • Available Monitor Outputs: 1:1 of Voltage Monitor Output 10:1 or 20:1 (switch selectable) • C€ Compliant Measurement and Power Solutions™ www.trekinc.com

Model 320C Specifications All specifications are with a probe-to-surface separation of 1 mm. Performance Features (cont.) Measurement Range 0 to ±100 V DC or peak AC. Sensitivity 1 mV. Accuracy Voltage Monitor Output Better than ±0.05% of full scale. Voltage Display Better than or equal to ±2 counts, referred to the voltage monitor. Speed of Response (10% to 90%) Less than 300 ms for a 100 V step. Stability Drift with Time Less than 50 ppm/hour, noncumulative. Drift with Temperature Less than 50 ppm/°C (1:1 monitor output). Less than 100 ppm/°C (10:1/20:1 monitor output). Features Null Voltage...