General Note

IRC reserves the right to make changes in product specification without notice or liability.

All information is subject to IRC’s own data and is considered accurate at time of going to print.

A subsidiary of

TT electronics plc

• 4222 South Staples Street • Corpus Christi Texas 78411 USA

Wire and Film Technologies Division

Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com

Molded Surface Mount

Wirewound Resistor

WSM Series

*Note: 5% or 10% preferred below 0.1 ohms.

Electrical Data

IRC

Type

Power Rating

@ 70°C

(watts)

Resistance

Range

(ohms)

Maximum Working

Voltage

(volts)

TCR

(ppm/°C)

Resistance

Tolerance

(%)

Standard

Values

Ambient

Temperature

(°C)

WSM-1

1W

0.01 to 1K

0.1

Ω - <10Ω: 100

≥1Ω: 20

*1, 2, 5, 10

E24

Preferred

-55 to 155

WSM-2

2W

0.01 to 2K

WSM-3

3W

0.01 to 3K

CONSTRUCTION

A high purity ceramic substrate is assembled with interference fit end caps to which are welded the terminations.

The resistive element is wound on the substrate and welded to the caps. The unit is then molded.

FLAMMABILITY

The resistor coating is categorized as flame retardant epoxy under UL-94.

SOLVENT RESISTANCE

The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed

circuits.

MARKING

WSM resistors are legend marked with type, value and tolerance.

WSM Series Issue December 2008 Sheet 1 of 3