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Simpson 444-220 Low Voltage Micro-Ohmeter
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Simpson 444-220
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Features:
- Runs on 220 Volts
- 20,000 Count 4 1/2 -Digit LCD
- 2 Measurement Methods: AC Pulse and DC Polarity Switching
- "Punch-Through" Prevention by 100 m 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
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Description
| Many of today’s advanced components require an accurate resistance measurement well
below the normal range of general purpose instruments. Simpson’s high precision Model 444 Micro-Ohmmeter fits this specialized requirement by measuring resistance from 1 micro-ohm to 20 ohms. It makes the measurement by 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 measur-ing modes: An automatic AC measurement mode and 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 444-220 is powered by a 220 AC source or, from self-contained rechargeable Ni-Cad batteries for field use. |
Models, Options, & Accessories
| Model |
Description |
List Price |
Sale Price |
| 444-220 |
MICRO-OHMMETER, 220V - Discontinued - no replacement |
| 444 |
MICRO-OHMMETER, 4.5, Item# 12681 |
$1623.69 |
| $1542.51 |  |
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| Model |
Accessories |
List Price |
Sale Price |
| 00827 |
LEAD, KELVIN, BNC |
$58.87 |
| $55.93 | |
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| 02151 |
PROBE SET, KELVIN PROD, BNC |
$220.90 |
| $209.86 | |
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| 45029 |
CASE, MOLDED PLASTIC, 444 SERIES |
$77.23 |
| $73.37 | |
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Specifications
| Ranges |
| Range |
Resolution |
Max. Test Current |
20mΩ
200mΩ
2Ω
20Ω |
1 μΩ
10 μΩ
100 μΩ
1mΩ |
5mA
500 μA
50 μA
5 μA |
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| General |
| 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 |
| Accuracy |
±(2% of input +150 counts) |
| Maximum Test Voltage |
100μV 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" |
| Conversion rate |
reading 2 per second |
| Test Leads |
BNC to dual Kelvin clip (2 leads) RG-58 |
| Operating Voltage |
220VAC ± 10%, 240VAC optional, 3VA typical |
| Operating Temperature Range |
0° to 50°C |
Storage Temperature Range |
-40° to +60°C |
| Relative Humidity |
90% maximum up to 35°C, 70% maximum up to +505°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" annuncia-tor 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. |
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