product guide
POWER RESISTORS
Series R
1/8W to 10W
FEATURES:
Series R meets or exceeds the electrical, mechanical enviromental and dimensional requirements of
Mil R-26
.05% to 10% tolerances All welded construction.
Higher temperature silicone or ceramic coating.
MATERIAL:
Core: Ceramic, Steatite or Alumnia depending
on size.
End Caps: Stainless steel
Coating: Special high temperature silicone or ceramic depending on end use. Standard Terminals: Tinned copperweld. Nickel available on request.
Resistance Element: Copper, nickel alloy or nickel chrome alloy, depending on resistance value.
ELECTRICAL:
Resistance Tolerance: Available down to ± .01% on certain values and sizes.
Standard Temperature Coefficient of Resistance:
PPM/°C Resistance
20 10 ohms & over
30 1 ohm - 10 ohms
90 Under 1 ohm
Dielectric Strength: 500 VAC for models up to & including 1 watt, 1000 volts for all others.
Short Time Overload: 5 seconds at 5 times rated power all models up to and including 3 watt
size. 5 seconds at 10 times rated power on all other styles.
POWER RATINGS:
R series have two power ratings depending on operating temperature and stability requirements.
Characteristics U: 275°C maximum hotspot temperature
.5% Maximum R in 2000 hour load file.
Characterisitc V: 375°C Maximum hotspot temperature
.3% Maximum R in 2000 hour load file.
DERATING:
R series have an operating temperature range of -55° to +350°C. They must be derated at high ambient temperature according to the chart at right.

Dimension Shown in Inches. Conversion to M.M. = Inch x 25.
M-O P/N Mil R-26 Equiv. Length (L)
±.032
Dia. (D)
±.032
Lead
(d) Awg
Wattage
U    V
Max.
Working Voltage*
U    V
Resistance
Ranges (Ohms)
.05% .1% .25% .5% 1%
3% 5%
R 1/8 na .140 .065 26 .20 na 10 na 10-500 .5-2k
R 1/4 na .250 .078 24 .40 na 20 na 10 - 950 1 - 3.4K
R 1/2 na .312 .078 24 .75 na 29 na 10 - 1.3K 1 - 4K
R-1A RW70 .406 .093 22 1.00 na 52 na 1- 2.7K .1 - 10.4K
R-1 na .531 .093 22 1.10 na 62 na 1- 4.0K .1 - 15K
R2A na .430 .175 20 2.00 2.75 130 150 1- 5K .01 - 20K
R2 1/2 RW69 .500 .210 20 2.50 3.25 138 157 1- 8.6K .01- 32.3K
R2 na .531 .160 20 3.00 3.75 135 148 1 - 5K .01 - 20K
R3A RW79 .602 .210 20 3.00 3.75 135 148 1 - 6.5K .01- 34.5K
R3 na .812 .210 20 3.25 4.75 185 220 1 - 11.4K .01- 42.1K
R4 na .625 .300 18 4.00 5.50 210 250 1 - 12.7K .01- 47.1K
R5 RW67 / RW74 .875 .300 18 5.00 6.50 330 376 .5 - 24.5K .01- 91.0K
R7 na 1.218 .375 18 7.00 9.00 504 576 .5 - 41.4K .01- 154K
R-10 RW68 / RW78 1.780 .375 18 10.00 13.00 799 911 .5 - 71.3K .01- 265K

*Figured on resistance values using .0008 diameter wire.
For non-inductive types add letter N after part number.
For ceramic coating add letter C after part number.

ORDERING INFORMATION
Example: 5W 10 ohm 5%
R5
10R0
J
Type
Resistance
Tolerance
4 digit. <100 use R for decimal. >100 4th digit is multiplier
J = 5%
F = 1%
D = .5%
C = .25%
B = .1%
A = .05%
TO ORDER PRODUCTS
E mail: microohm@mail.com
Call Toll Free: 1-800-845-5167

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bare axial