Four-terminal Kelvin Connected Resistors (LRD)

Direct's open air 4-terminal kelvin connected resistors (LRD)
tackle current sensing applications.

Always preferred in current sense applications, Direct's LRD Series range is available in the 1W, 3W, 5W, 7W and 10W packages, resistance values down to 0.001 ohm, with tolerances as tight as 0.50% and TCRs of 50ppm standard.

The 4 Lead Kelvin configuration enables current to be applied through two opposite terminals and a sensing voltage to be measured across the other two terminals, eliminating the resistance and temperature coefficient of the terminals for a more accurate current measurement.

With up to 10W power rating and TCRs as low as 50ppm/°C, the LRD 4-Lead Kelvin resistors deliver excellent performance, making them ideal for a variety of applications. The resistor is constructed using a low-resistance, low-inductance, high-impulse proprietary metal element that gives the device its extended power and temperature ratings.

Continually upgrading its current sense resistors to take advantage of modern technologies and manufacturing methods, Direct is now able to offer complete ranges of products which meet the RoHS requirements and in addition to detailing these, the component selector also provides designers with a comprehensive selection of application notes.

The Open Air (LRD) Kelvin 4-terminal Resistor can be manufactured to custom length/width for use as a current shunt. Direct will also produce outside these specifications to meet customer requirements. Contact us with your specific needs. Download PDF Specification Open Air Four-terminal Kelvin Connected Resistors (LRD).

Features :
  1. Low inductance.
  2. 4 leads for Kelvin connection.
  3. Decimal marked, silicone coated.
  4. Tinned copper terminal for easy soldering.
  5. Radial, self-supporting, design is ideal for PC board mounting.
Applications :
  1. Surge/Pulse Applications.
  2. Current Sensing Application.
  3. Feed Back & Motor Control.
  4. High Precision Measurement Instrumentation.
Specification & Dimensions (Unit: mm) (LRD)
4-Terminal Current Sensing Open Air (LRD) Dimensions
4-Terminal Current Sensing Open Air (LRD) Dimensions
Type Rating Current Resistance Range (mΩ) Tolerance (%) TCR (ppm/°C)
LRD-1 1A 1 ~ 10 mΩ D(±0.5%)
F(±1%)
G(±2%)
J(±5%)
±10 ppm/°C
±20 ppm/°C
±25 ppm/°C
±50 ppm/°C
±100 ppm/°C
LRD-3 3A 1 ~ 10 mΩ
LRD-5 5A 0.5 ~ 5 mΩ
LRD-7 7A 0.3 ~ 3 mΩ
LRD-10 10A 0.1 ~ 1 mΩ
Power Derating Curve (LRD)
(LRD) Power Derating Curve
(LRD) Power Derating Curve
Characteristic Specification & 4-Lead Kelvin Connections (LRD)
4 Lead Kelvin Connections (LRD)
4 Lead Kelvin Connections (LRD)
Test Items Test Method Specification
Operating Temperature Range   -55°C ~ 125°C
Maximum Working Voltage   (P40°C x R)1/2
Terminal Tensile Strength 50N, 10s ΔR≤±1.0%R
Withstand Voltage 1000V, 1 Min. No damage on the appearance.
Short Time Overload 5 times rated power, 5s ΔR≤±4.0%R
Thermal Shock -55°C~+125°C, 5 cycles, 30 min. ΔR≤±5.0%R
Load Life 70°C, 1000h 1.5 hours on, 0.5 hours off. ΔR≤±5.0%R
Order Codes (LRD)
LRD - 5 R005 F P
 
Part Number
LRD
 
Rated Current (A)
1 1 A
3 3 A
5 5 A
7 7 A
10 10 A
Resistance Value (Ω)
R005 0.005Ω
R05 0.05Ω
R1 0.1Ω
Tolerance %
D ±0.5%
F ±1%
G ±2%
J ±5%
Package
P Bulk