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Document Number: 28737

126

Revision: 21-Feb-08

NFR25/25H

Vishay BCcomponents

Fusible, Non-Flammable Resistors

A homogenous film of metal alloy is deposited on a high

grade ceramic body. After a helical groove has been cut in

the resistive layer, tinned connecting wires of electrolytic

copper are welded to the end-caps. The resistors are coated

with a grey, flame retardant lacquer which provides

electrical,

mechanical,

and

climatic

protection.

The

encapsulation is resistant to all cleaning solvents in

accordance

with

“MIL-STD-202E,

method 215”,

and

“IEC 60068-2-45”.

FEATURES

• Wide range of overload currents

(refer Fusing Characteristics graphs)

• Lead (Pb)-free solder contacts

• Pure tin plating provides compatibility with lead (Pb)-free

and lead containing soldering processes

• Compatible with “Restriction of the use of Hazardous

Substances” (RoHS) directive 2002/95/EC (issue 2004)

APPLICATIONS

• Audio

• Video

Notes:

•

R value is measured with probe distance of 24 ± 1 mm using 4-terminal method

12NC INFORMATION

• The resistors have a 12-digit numeric code starting with 23

• The subsequent 7 digits indicate the resistor type and

packaging

• The remaining 3 digits indicate the resistance values:

– The first 2 digits indicate the resistance value

– The last digit indicates the resistance decade

Last Digit of 12NC Indicating Resistance Decade

12NC Example

The 12NC for a NFR25 resistor with value 750

Ω, supplied

on

a

bandolier

of

1000 units

in

ammopack

is:

2322 205 13751.

TECHNICAL SPECIFICATIONS

DESCRIPTION

VALUE

NFR25

NFR25H

0.22

Ω to 15 kΩ

Resistance Tolerance and Series

± 5 %; E24 series

Maximum Dissipation at

0.5 W

Thermal Resistance

240 K/W

150 K/W

Temperature Coefficient:

0.22

4.7

15

Maximum Permissible Voltage (DC or RMS)

250 V

350 V

Basic Specifications

IEC 60115-1 and 60115-2

Climatic Category (IEC 60068)

55/155/56

Stability After:

Load

ΔR max.: ± (1 % R + 0.05 Ω)

Climatic Tests

ΔR max.: ± (1 % R +0.05 Ω)

Soldering

ΔR max.: ± (0.25 % R +0.05 Ω)

RESISTANCE DECADE

LAST DIGIT

0.22 to 0.91

Ω

7

1to9.1

Ω

8

10 to 91

Ω

9

100 to 910

Ω

1

1to9.1 k

Ω

2

10 to 15 k

Ω

3