FHR FNR 2-T238 4-T238 • Extremely Low Ohm Rating • High Stability • Two- and Four Circuit Technology • Low Temperatur Coefficient • Low Electrical Noise • Low Inductance SPECIFICATIONS ELECTRICAL FHR 2/4-T238 FHN 2-T238 FNR 2/4-T238 FNN 2-T238 Resistance Range : R01/R001...100R R01/R001...100R Power Rating : 60 W* * with heatsink 80 W* 1.3 K/W 1.0 K/W Thermal Resistance Rthj-c : Tolerances : 0.5%, 1%, 2%, 5% (other Tolerances upon request) Stability : 0.5 Temperatur Coefficient : ±15 ppm/K (20...60)°C / ±50 ppm/K (-40...130)°C R < R02: ±20 ppm/K (20...60)°C FHR/FNR2-T238 as well as FHN/FNN TCR-Shift depending on the resistor value Voltage Proof : 2.5 kVDC Thermal EMF : < 1 µV/K Max. Current : 40 A 45 A (higher Values upon request) ENVIRONMENTAL Operative Temperature Range : MECHANICAL Resistor Material Substrate Housing Connector Material : : : : -40°C...130°C Metalfoil CuNiMn ( DIN 17471) Al2O3 AlN Epoxy Cu or brass, tinned 2-pin, 4-pin Willow Technologies Ltd. Shawlands Court, Newchapel Road, Lingfield, Surrey, RH7 6BL, UK Tel. + 44 (0) 1342 835234, Fax. + 44 (0) 1342 834306, e-mail [email protected] web www.willow.co.uk FHR FNR 2-T238 4-T238 TEMPERATURE COEFFICIENT (FHR/FNR and FHN/FNN 2-T238) 6000 250 - 50 ppm/K + 15 ppm/K 2000 0 - 15 ppm/K -2000 Limit 2 (3σ) 200 150 100 50 Nom inal dR/R -4000 0 Limit 1 (3σ) -6000 -40 300 TCR - Shift (ppm/K) dR/R (ppm ) 4000 + 50 ppm/K -20 0 20 40 60 80 100 120 2 5 10 20 140 Tem perature (°C) DERATING CURVE Power ( % from nominal power) 120 100 80 60 40 20 0 25 50 85 100 50 100 Resistance Value (m Ohm ) 115 130 Tem perature of the backplate (°C) DIMENSIONS * screw terminal M4 Standard: Pin G (width= 6.35) leads curved Dimensions in mm Willow Technologies Ltd. Shawlands Court, Newchapel Road, Lingfield, Surrey, RH7 6BL, UK Tel. + 44 (0) 1342 835234, Fax. + 44 (0) 1342 834306, e-mail [email protected] web www.willow.co.uk FHR FNR 2-T238 4-T238 FAULTY CONNECTION VARIATIONS FHR/FNR 2-T238 FHR/FNR 4-T238 1 - U1 / 2 - U2 / 3 - I2 / 4 - I1 Dimensions in mm HOW TO ORDER FHR 2-T238 1R1 G 1% FNR 4-T238 R001 F 2% Willow Technologies Ltd. Shawlands Court, Newchapel Road, Lingfield, Surrey, RH7 6BL, UK Tel. + 44 (0) 1342 835234, Fax. + 44 (0) 1342 834306, e-mail [email protected] web www.willow.co.uk