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LFR Clip On Current Probes

For Oscilloscopes, Power Analysers and Wattmeters

Single phase clip around / Clip on flexible AC current sensing probes Converting ac current to an isolated voltage (Instantaneous) For fast & easy installation in confined spaces

The LFR ac current probe has been designed to offer market leading low frequency performance, meaning high accuracy, low phase shift and low noise. This compact, low cost, clip-around probe is both flexible and dual-range, and is optimized to give minimal phase measurement error at frequencies from 45Hz to 20kHz and have a very low noise floor.

The LFR current sensors convert ac current to an isolated 0-6V voltage signal. The available LFR ranges are 0-60A to 0-60,000Apk. The LFR offers accurate measurement over a wide bandwidth ensuring precise measurement even with harmonically distorted waveshapes - using a flexible clip-on sensing coil.

Typical applications: Extending current ranges of power analyzers, wattmeters, oscilloscopes, data loggers, where energy and current monitoring is required. Typical loading situations are ac/dc Wind turbines, VFD motor drives, arc welding, power conversion and power distribution. For all LFR models, a NIST/NPL (UKAS) traceable calibration certificate and certificate of conformance is supplied. All LFR current sensors use UL or CSA approved materials.


Performance summary LFR wideband current sensing probe

  • Peak Current ratings from 60A to 60kA
  • Dual Sensitivity set to give ±6Vpk output (e.g. 10mV/A for ±600Apk AND 1mV/A for ±6000Apk, switch selectable)
  • Typical Bandwidth 0.1Hz to 1MHz
  • Robust, flexible, clip-around coils
  • Standard lengths 300, 500, 700 or 1000mm
  • Custom lengths up to 5m
  • Coil thickness 8.5mm
  • Insulation 2kV pk
  • Both battery (1x9V PP3) and external DC power supply
  • CE marked

LFR Specifications

Type Sensitivity
Peak current
Noise typ.
(mV rms)
Phase error at 50Hz
LF (3dB)
bandwidth typ. (Hz) FL
Phase error in
degrees at 20kHz
typ. (deg)
Peak di/dt
x10 x1 x10 x1 x10 x1 Coil 300mm Coil 700mm x10 x1
LFR 03/3 100.0 10.0 60.0 600.0 3.0 1.0 <0.85° 0.45 1.8° 3.0° 0.015 0.25
LFR 06/6 50.0 5.0 120.0 1.2k 3.0 1.0 <0.50° 0.23 1.8° 3.0° 0.03 0.5
LFR 1/15 20.0 2.0 300.0 3.0k 2.0 1.0 <0.35° 0.15 1.8° 3.0° 0.1 1.2
LFR 3/30 10.0 1.0 600.0 6.0k 2.0 1.0 <0.25° 0.10 1.8° 3.0° 0.2 2.5
LFR 6/60 5.0 0.5 1.2k 12.0k 2.0 1.0 <0.20° 0.08 1.8° 3.0° 0.4 5.0
LFR 15/150 2.0 0.2 3.0k 30.0k 1.0 0.5 <0.18° 0.07 1.8° 3.0° 0.9 6.0
LFR 30/300 1.0 0.1 6.0k 60.0k 1.0 0.5 <0.18° 0.07 1.8° 3.0° 1.8 6.0
High Freq Bandwidth -3dB
1.0MHz for coil length 300mm
600kHz for coil length 700mm
Typical accuracy
±0.3% with conductor centered in sense coil (Rogowski loop). Accuracy variation with conductor position is ±1%
Typical linearity
±0.05% (full scale)
DC Offset
Absolute maximum values of di/dt in
kA/uS(value must not be exceeded)
Peak 6.0
RMS 0.3 @ 70°C
Coil and cable
300, 500, 700 or 1000mm
8.5mm (14mm with sleeve)
14.0mm (with protection sleeve)

Safe peak working voltage to earth. The coils are flash tested at 4kVrms for 60 seconds. The coil is supplied with a removable silicone sleeve for additional mechanical protection. Information about continuous use of the coils at high voltage can be obtained from Powertek.

-20°C to 70°C

For de-rating due to temperature cycling please consult Powertek

3 CABLE LENGTH (from box to coil)
2.5 m
Power Supply
Single 9V PP3 battery - battery life typically 50 hours. Also supplied with 2.1 / 2.5mm socket for 12V to 24Vdc ( ±10% ) DC supply - (Quiescent current 10mA). Optional power supply available from Powertek. Battery inoperative with DC supply present.
Integrator Box Dimensions
H = 28mm, W = 65mm, D = 90mm
Output Socket
BNC (output impedance 50ohm - unit supplied with 0.5m BNC-BNC coaxial cable) Optional 0.5m BNC to banana plug available from Powertek.
Min. output loading
100k (for rated accuracy).
Temperature Range
-10°C to 55°C
LFR current sensor order codes

Type & model / Coil circumference

LFR 06/6 / 700 mm

In this example supplied as 120A & 1200Apk, 0-6V output with 12-24Vdc power and 700mm coil length

* to meet CE / UL safety requirements, an external power adapter is supplied for 125Vdc, 110Vac and 230Vac options

All products have CE, IEC, EN, ASME or BS approvals.