Dimensions (mm) and weight (g)
Type
L
D
D1
K
Weight
max
min
WRM 0102
2.2
1.1
0.35
0.01
WRM 0204
3.
6
1.4
0.5
0.02
WRM 0207
6.
0
2.
2
2.2
1.1
0.08
Mini Melf
Resistors
WRM Series
High reliability
Predictable pulse handling capability
Tolerances down to 0.1%
TCR down to 5 ppm/°C
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info@welwyn-tt.com Website: www.welwyn-tt.com
WRM 0102
WRM 0204
WRM 0207
Power rating at 70°C
watts
0.2
0.25
0.4
Resistance range
ohms
R22 – 2M21
R22 – 10M
R22 – 8M2
Limiting element voltage
volts
150
200
250
TCR
ppm/°C
15, 25, 50
5, 15, 25, 50
25, 50
Resistance tolerance
%
0.1, 0.25, 0.5, 1.0, 2, 5
Standard values
E24 & E96
Thermal impedance
k/W
250
200
140
Ambient temperature range
°C
-55 to +125
Insulation resistance
ohms
>1010
Electrical Data
Physical Data
Issue D 09.06
A subsidiary of
TT electronics plc
Welwyn Components
L
K
L1
D
D1
Construction
A metal film is deposited onto a high dissipation ceramic
former to which tin plated teminating caps are fitted.
The resistor is adjusted to value by a helical cut in the film
and the body is protected by a lacquer coating.
Marking
Resistance values are colour coded with 4 or 5 bands
depending on type.
Terminations
Material
Plated steel cap.
Solderability
The pure tin finish produces ageing free
contacts on which low melting solders can
be used. Dipped area shall be covered with
a smooth and bright solder coating after
3 seconds immersion at 215°C.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuit boards.