12681-NIST Simpson

444-2 Low Voltage Micro-Ohmeter Measures from 50 Micro-Ohm to 20 Ohms Simpsons high precision Model 444-2 has been redesigned for added ESD immunity and longer battery life. The model 444-2 Micro-Ohmmeter measures resistance from 50 micro-ohm to 20 ohms. It measures using an extremely small test voltage (100 microvolt maximum) and a four wire measurement technique. The resistance reading is indicated on a 4-1/2 digit LCD display using one of two measuring modes: An automatic AC measurement mode or a manual DC measurement mode. By limiting the test voltage of the Model 444-2 to only 100 micro volts the instrument will notpunch throug contamination or corrosion. An audible tone can be used to indicate resistance values below any selected reading. The Model 444-2 has a universal power input range of 85Vac to 250Vac and incorporates a self-contained rechargeable 20,000 Count 4 1/2-Digit LCD 2 Measurement Methods: AC Pulse and DC Polarity Switching Punch-Throug Prevention by 100V Max. Test Voltage User-Adjustable, Low-Resistance Alarm AC Test Mode Cancels Offset Voltages and Thermocouple Effects Includes Ni-Cad Battery for Field Use and Test Leads Extended Battery Life, 10 Hours Typical Ordering Information Micro-Ohmmeter Catalog Number 444-2 Micro-Ohmmeter, 85V/250V 12681 Accessories Catalog Number Standard Test Lead Set 00827 Kelvin Test Probe Set 02151 Case, Molded Plastic 45029 1 Rev. 05-19444-2 Low Voltage Micro-Ohmeter Maximum Range Resolution Test Current 20m 1 5mA 200m 10 500A 2 100 50A 20 1m 5A Accuracy (0.05% of input 600 counts) DC mode (0.05% of input 15 counts) AC mode Alarm Resistance below set point activates audible beeper and display annunciator. Resistance above set point activates display annunciator Set Point Adjustment Front Panel Knob Set Point Accuracy (2% of input +150 counts) Maximum Test Voltage 100V peak Measurement Techniques (AC) Pulse of 40 Hertz Square Wave and DC Switchable Polarity Display 19,999 counts, 4.5 digits LCD type, 0.5 high, andACD and annunciators Conversion Rate Reading 2 per second Test Leads BNC to dual Kelvin clip (2 leads) RG-58 Operating Voltage 85VAC to 250VAC, 10VA maximum Operating Temperature Range 0 to 50C Storage Temperature Range -40 to +60C Relative Humidity 90% maximum up to 35C, 70% maximum up to +50C (non-condensing) 0.2%/C (0 to 18C and 28 to 50C) Extended Battery Life Typical 10 hours Battery Mode Rated Circuit-To-Ground Voltage 30V (RMS) Display Settling Time <15 seconds Dimensions 2.7 x 8.4 x 9.0 (68 x 213 x 228 mm) nominal Weight Approximately 3 Ibs. 2 Rev. 05-19