Ultra Precision
Metal Film Resistors
MAR 40/42 series
Welwyn Components
•
Tolerance down to 0.005%
•
Very low TCRs
•
Rugged moulded protection
•
Matched sets available
Electrical Data
Notes
Power rating at 85°C
Resistance range
Limiting element voltage
TCR (0°C to +60°C)
TCR (-55°C to +125°C)
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
°C/watt
°C
watts
ohms
volts
ppm/°C
ppm/°C
%
0.3
20R0 to 400K
250
2 (T18) & 5 (T16)
5 (T18) & 10 (T16)
0.005, 0.01, 0.02, 0.05, 0.1, 0.25, 0.5 & 1
E24, E96 preferred
80
- 55 to +155
Any value to order
Higher values by agreement
Physical Data
Dimensions (mm) and Weight (g)
Type
MAR 40
MAR 42
L max.
7.75
8.25
H max.
8.64
8.64
W max.
3.3
3.3
T min.
25.4
25.4
d nom.
0.6
0.6
S nom.
3.8
5.1
Wt.
nom.
0.65
0.65
H
L
W
T
S
d
Construction
Ceramic rods are coated with a metal film and plated steel
caps are force fitted. A helical cut is used to adjust the film to
its final value. Termination wires are welded to the caps and
the resistor is protected with a multiple lacquer coat and
encapsulated in an epoxy moulded protection.
Marking
Type reference, TCR code, resistance value and tolerance. The
resistance value marking conforms to IEC 62.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning fluids suitable for printed circuits.
Terminations
Material
Strength
Solderability
Solder-coated copper wire.
The terminations meet requirements of
IEC 68.2.21 and MIL-STD 1276.
The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2 and MIL-STD 202.
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
Issue B · 03.02
© 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
180
WELWYN [ WELWYN COMPONENTS LIMITED ]
