GR precision wirewound resistors provide a higher resistance stability and a higher initial calibration accuracy than any other class or resistor. They also offer excellent noise levels and lower temperature coefficients.
Description
Innovators and manufacturers of ultra-precision wirewound resistors and test instruments used as laboratory standards and for critical process monitoring.
General Resistance ultra-precision resistors have been used for over 50 years in precision measurement instruments by manufacturers around the world.
GR precision wirewound resistors should be specified whenever precision circuit operation is to be maintained over a prolonged period of time.
These resistors provide a higher resistance stability and a higher initial calibration accuracy than any other class of resistor. They also offer excellent noise levels and lower temperature coefficients.
The highest quality materials are used in the manufacture of these essential circuit elements. General Resistance design engineers customarily employ high quality copper alloys such as Evanohm, Karma, Moleculoy, Stabilohm, Zeranin and equivalent in order to achieve higher predictability and flatter temperature responses. And all critical manufacturing stages are conducted in environmentally controlled "clean rooms."
- Standard resistance range: any value from 1 ohm to 1.1 Megohms.
- Standard accuracies: +/-0.1%, +/-0.025%, and +/-0.01%.
- Standard tempco: +/-5ppm/°C max (-55°C to +125°C)
- Special order: virtually any accuracy, tempco, resistance value or ratio matching required by your specific application.
GR maintains substantial quantities of standard accuracies as listed:
| 10 |
200 |
1.0k |
10k |
100k |
| 20 |
250 |
1.5k |
20k |
180k |
| 30 |
300 |
2.0k |
30k |
200k |
| 40 |
350 |
2.5 |
40k |
250k |
| 50 |
400 |
3.0k |
50k |
300k |
| 60 |
500 |
4.0k |
60k |
400k |
| 70 |
600 |
5.0k |
70k |
500k |
| 80 |
700 |
6.0k |
80k |
1 Meg |
| 90 |
800 |
7.0k |
90k |
|
| 100 |
900 |
8.0k |
|
|
| 120 |
|
9.0k |
|
|
General Specifications
Electrical
| Standard accuracies (@ +25°C) |
±0.1%, ±0.025%, ±0.01% |
| Voltage coefficient |
Essentially "zero" |
| Thermal emf |
1.5µV/°C typ. |
|
Lead resistance (@ +20°C):
24 AWG (0.4mm)
22 AWG (0.6mm)
20 AWG (0.8mm) |
213.0µO/0.1 in. (84µO/mm)
134.5µO/0.1 in. (53µO/mm)
84.6µO/0.1 in. (33.3µO/mm) |
| Noise |
Immeasurable |
Mechanical
| Resistance Wire |
Highest quality copper alloy drawn from melts of known resistivity and controlled Temco |
| Winding |
Balanced muliple p for low reactance |
| Protection |
Hand-applied RTV silicone coating |
| Outer casing |
Molded shell sealed with epoxy |
| Marking |
Permanent ink, direct reading |
| Leads |
Axial, tinned copper |
Specifications: GR compared to Mil Specs
|
MIL-R-93 Limit |
MIL-R-39005 Limit |
GR (typ.) |
Minimum insulation resistances:
Dry/Wet (?R) |
>109O/108O |
>109O/108O |
>1010O/109O |
| Temperature Cycling (?R) |
±(.2% +50mO) |
±(.05% +10mO) |
±(.001% +5mO) |
| Short-term overload (?R) |
±(.1% +50mO) |
±(.01% +10mO) |
±(.003% +5mO) |
| Moisture resistance (?R) |
±(.1% +50mO) |
±(.1% +10mO) |
±(.001% +3mO) |
Dielectric withstanding voltage
@ atm. pres. (VRMS) |
500 |
750 |
1000 |
Load life, full rated power
@ 70°C (?R) |
±(.5% +50mO) |
-- |
±(.0035% +5mO) |
High temp. exposure
@ 150°C (?R) |
±(.1% +50mO) |
±(.1% +10mO) |
±(.001% +5mO) |
| Low temp. operation (?R) |
±(.25% +50mO) |
±(.1% +10mO) |
±(.001% +3mO) |
| Resistance to soldering heat (?R) |
N/A |
±(.01% +10mO) |
±(.001% +3mO) |
Shock & vibration
(high frequency) (?R) |
±(.1% +50mO) |
±(.01% +10mO) |
±(.001% +3mO) |
Listing of all applicable MIL Specifications:
- MIL-R-93: Precision Wirewound Resistors
- MIL-R-39005: High Reliability Wirewound Resistors
- MIL-STD-883, Method 2003: Solderability
- MIL-STD-202, Method 208: Solderability
- MIL-STD-202, Method 210A, Cond. C: Resistance to Soldering Heat
- MIL-STD-202, Method 215: Marking Resistance to Solvents
- MIL-STD-202, Method 106D: Moisture Resistance
- MIL-STD-202, Method 102A, Cond. C: Temperature Cycling
- MIL-STD-202, Method 301 Dielectric Withstanding
- MIL-STD-202, Method 302 Cond. A or B: Insulation Resistance
- MIL-STD-202, Method 205D, Cond. C: Shock
- MIL-STD-202, Method 204B, Cond. D: Vibration
- MIL-STD-202, Method 211A, Cond. A and D: Terminal Strength
Power Derating Curve:
All GR Precision Wirewound Resistors
Power dissipation at ambient temperature: GR resistors are designed to operate at full load up to +85°C. At temperatures in excess of +85°C derating curves must be observed. If power ratings are exceeded, the resistor may not perform at specified accuracy.
