Mini Melf
Resistors
Welwyn Components
WRM Series
• High reliability
Predictable pulse handling capability
•
Tolerances down to 0.1%
•
TCR down to 5 ppm/°C
•
Electrical Data
WRM 0102
0.2
WRM 0204
WRM 0207
0.4
Power rating at 70°C
Resistance range
watts
ohms
volts
0.25
R22 – 10M
200
R22 – 2M21
150
R22 – 8M2
250
Limiting element voltage
TCR
ppm/°C
%
15, 25, 50
5, 15, 25, 50
0.1, 0.25, 0.5, 1.0, 2, 5
E24 & E96
200
25, 50
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
Insulation resistance
k/W
°C
250
140
-55 to +125
>1010
ohms
Physical Data
Dimensions (mm) and weight (g)
L
Type
L
D
max
D1
max
K
min
Weight
max
D1
L1
D
WRM 0102
WRM 0204
WRM 0207
2.2
3.6
6.0
1.1
1.4
2.2
1.1
1.4
2.2
0.35
0.5
0.01
0.02
0.08
K
1.1
Construction
A metal film is deposited onto a high dissipation ceramic
Terminations
Material
Plated steel cap.
former to which tin plated teminating caps are fitted.
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.
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.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuit boards.
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.
A subsidiary of
TT electronics plc
© 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
Issue D · 09.06
TTELEC [ TT Electronics ]
