Featuring the latest in pulse width modulation technology, the Model 4120 employs a high frequency power source and voltage/current feedback circuits to product a stable, high voltage output with low ripple. A front panel feature, unique to the Model 4120 allows the operator to test Metal Oxide Arresters quickly and accurately. Another feature that is as unique as it is useful is a high-voltage dc micro-ammeter use to test leakage currents on the high-voltage side of the insulation testing circuit. Features Pulse width Modulation (PWM) technology Stable, high-precision voltage adjustment Comprehensive nanosecond threshold protection Unique Metal oxide test function Adjustable overvoltage protection feature Current limiting resistor for capacitive load testing Shielded HV micro-ammeter accessory Shorting rod for grounding output after testing > Specifications Rated voltage: 120 kVDC Rated current: 5 mADC Rated power: 360 W Weight: 22 lbs. Power supply: 120 VAC ±10%, 60 Hz Dimensions (Control Unit): 16.25 x 15.5 x 7.5 Output voltage accuracy: ±(1.0% reading, ±2 digits) Output current accuracy: ±(1.0% reading, ±2 digits) Ripple factor: ?0.5% Working mode: Intermittent use, 30 minutes under rated load Overload Voltage: The no-load voltage can exceed the rated voltage 10% for 10 minutes. Overload Current: The maximum charge current is 1.25 times of the rated current. Operating environment: Temperature 14°F to 104°F Humidity: To ?85%RH for temperatures under 77°F, non-condensing Altitude: Under 4,900 > Each Unit Includes Manual, power cord, and NIST Traceable Certificate of Calibration.