12681 (444) Simpson, 12681 (444) Datasheet
![MICRO OHMETER, 4 WIRE, 20OHM](/photos/23/51/235148/3770624_sml.jpg)
12681 (444)
Manufacturer Part Number
12681 (444)
Description
MICRO OHMETER, 4 WIRE, 20OHM
Manufacturer
Simpson
Datasheet
1.12681.pdf
(1 pages)
Specifications of 12681 (444)
Wire Connection
4-Wire
Resistance Measuring Range
1 MOhm To 20 Ohm
Resolution (ohm)
1mohm
Test Current
5mA
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Simpson’s high precision Model 444 Micro-Ohmmeter measures resistance from 1
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 to only 100 micro volts the
instrument will not "punch through" contamination or corrosion. An audible tone
can be used to indicate resistance values below any selected reading. The Model
444 is powered by either a 120 or 240 AC source or, from self-contained
rechargeable Ni-Cad batteries for field use.
Specifications
Accuracy:
Alarm: Resistance below set point activates audible beeper and display annunciator.
Resistance above set point activates display annunciator.
Set point Adjustment: Front Panel Knob
Accuracy:
Maximum Test Voltage: 100 V peak
Measurement Techniques: (AC) Pulse of 40 Hertz Square Wave and DC Switchable
Polarity
Display: 19,999 count LCD with 0.5" digits and "AC," "DC" and "
Conversion rate: reading 2 per second
Test Leads: BNC to dual Kelvin clip (2 leads) RG-58
Operating Voltage: 120VAC
Operating Temperature Range: 0° to 50°C
Storage Temperature Range: -40° to +60°C
Ordering Information
• 20,000 Count 4
• 2 Measurement Methods: AC Pulse and DC Polarity Switching
• 8"Punch-Through" Prevention by 100 V 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
Measures from 1 Micro-Ohm to 20 Ohms
MICRO-OHMMETER
444 Micro-Ohmmeter, 120V
444 Micro-Ohmmeter, 240V
(0.05% of input
200m
Range
20m
20
2
(0.05% of input
(2% of input +150 counts)
15 counts) AC mode
1
/
2
-Digit LCD
Resolution
600 counts) DC mode
10%, 240VAC optional, 3VA typical
100µ
10µ
1m
1µ
Catalog No.
12681
12682
Maximum Test Current
ACCESSORIES
Standard Test Lead Set
Kelvin Test Probe Set
p
q
500µA
" annunciators
50µA
5mA
5µA
444 Low Voltage Micro-Ohmeter
Specifications (Continued)
Relative Humidity: 90% maximum up to 35°C,
70% maximum up to +50°C (non-condensing)
Temperature Coefficient: 0.1 times the applicable accuracy specification per
°C (0° to 18°C and 28° to 50°C)
Battery Voltage Effect: Plus or Minus (0.15% of input); Fully charged to "B"
annunciator displayed
Battery Life: 8 hours typical
Rated Circuit-To-Ground Voltage: 30V (RMS)
Dimensions: 2.7" x 8.4" x 9.0" (68 x 213 x 228 mm) nominal
Weight: Approximately 3 Ibs.
Catalog No.
00827
02151
ACCESSORIES
Case, Molded Plastic
Catalog No.
rev_1 11/2/04
45029