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CWT Mini Clip On High Frequency Current Probe

Rogowski Coil Current Sensor - Miniature High Frequency Probe

The CWT Miniature current probes utilize a Rogowski Coil sensor thin enough (typical cross section 3.5mm) to fit in very confined spaces - often between the legs of a semiconductor power switching device. With high frequency bandwidths up to 20MHz, the CWT miniature Rogowski coil is ideal for measuring switching transients or pulsed currents starting at 300mA up to 300kA in power electronic equipment. The CWT miniature Rogowski probe is a clip around flexible coil current probe based on the Rogowski principle to achieve high bandwidth measurement and faithful conversion of current to voltage, intended for use with oscilloscopes, data loggers, power meters and power analyzers. Available with a 100mm or 200mm length clip-around coil, ensuring easy current monitoring even where access is limited.

CWT Mini Rogowski Coil

CTW Mini Rogowski Coil Clip on Current Probes

The CWT miniature Rogowski coil range from Powertek, combines state of the art performance of the CWT ac current probe but features a miniature clip around Rogowski coil capable of monitoring currents in even the most difficult to reach parts of the circuit.
Full specifications for the CWT Miniature Rogowski coil range are available in the CWTmini datasheet

Available kA Peak Current ratings 0.03, 0.06, 0.15, 0.3, 0.6, 3.0, 6.0, 12, 30, 60, 120, 300

Sensitivity set to give ± 6 volts peak output (e.g. 1.0mV/A for ± 6000A peak)

Typical Bandwidth 0.1Hz to 17MHz

Accuracy typically 2% of reading

DC offset no greater than 2mV

Thin - flexible - clip-around coils

  • Coil lengths of 100 and 200mm
  • Rogowski Coil cross sectional diameter 3.5mm for 2kV isolation and 4.5mm for 5kV isolation
  • Peak voltage isolation either 2kV or 5kV

Cable length - The cable connecting the cable to the integrator box comes in lengths from 1m to 4m.

Integrator power supply

  • Either Battery 4 AA 1.5V standard alkali batteries typical life 70hrs plus- 2.1mm/2.5mm socket for 12 to 24V DC input (batteries inoperative when DC supply present)
    or Rechargeable NiMH Batteries typical life 30hrs
    plus - 2.1mm/2.5mm socket for 12 to 24V DC input (batteries trickle charged when DC supply present)
    An AC/DC adapter is included for use with the CWT details can be found in Euro_adapter.pdf, UK_adapter.pdf and USA_adapter.pdf.

CE marked

Selection Table for CWT Mini Clip On Current Probes

CWT Mini Rogowski Coil Specifications
Type Sensitivity
Peak current
Peak di/dt
Noise max*1
mV pk-pk
(%/ ms)
LF (3dB)
typ. (Hz) fL
Phase lead at 50Hz
typ. (deg)
HF (3dB) bandwidth
typ. (MHz) fH*2
Coil Length
Coil Length
High Sensitivity Ranges of CWT .... measuring currents from 300mA
CWT015 200.0 0.03 0.2 6.5 130 150 2.0@6kHz 5.0 3.5
CWT03 100.0 0.06 0.4 4.5 90 105 2.0@4kHz 8.5 5.5
CWT06 50.0 0.12 0.8 3.0 70 80 2.0@3kHz 17 12
CWT1 20 0.3 2.0 2.5 40 50 1.9@2kHz 17 12
CWT3 10.0 0.6 4.0 8.0 3.0 3.5 1.0@300Hz 17 12
Standard Ranges of CWT .... measuring currents from 15A
CWT6 5.0 1.2 8.0 14.0 0.9 1.0 1.7 17 12
CWT15 2.0 3.0 20.0 7.0 0.7 0.8 1.3 17 12
CWT30 1.0 6.0 25.0 5.0 0.5 0.6 0.9 17 12
CWT60 0.5 12.0 25.0 3.5 0.35 0.4 0.6 17 12
CWT150 0.2 30.0 25.0 3.0 0.2 0.2 0.3 17 12
CWT300 0.1 60.0 25.0 3.0 0.1 0.1 0.2 17 12
CWT600 0.05 120.0 25.0 3.0 0.06 0.05 0.1 17 12
CWT1500 0.02 300.0 25.0 3.0 0.035 0.03 0.06 17 12

*1Distributed around the fL (3dB) bandwidth.

*2The high frequency bandwidth is in part dependent on coil length. Contact Powertek for values of fH for other coil lengths

CWT LF Mini Datasheet
(full scale)
Calibrated to UKAS ±0.2% with conductor central in the loop
Variation with conductor position in the coil loop typically ±2%
±0.05% (full scale)
(value must not be exceeded)
CWT 015, 03, 06
PEAK 25.0
RMS 0.6 @ 70℃
PEAK 25.0
RMS 1.0 @ 70℃
all other CWT's
PEAK 25.0
RMS 1.2 @ 70 ℃ (further information available on request)
Coil and cable
100 or 200mm optional lengths to 1000mm
3.5mm for 2kV isolation
4.5mm for 5kV isolation
2 or 5kV

Safe peak working voltage to earth. 2kV coils are flash tested at 3.8kV/60Hz for 60 seconds and 5kV coils are flash tested at 8kVrms/60Hz for 60 seconds. Information about the continuous use of coils at high voltage can be obtained from Powertek

-20°C to 100°C

For de-rating due to temperature cycling please consult Powertek

CABLE LENGTH (metre) (from box to coil)
2.5 or 4m
Max cable length for CWT015 is 1m, CWT03 is 1.5m, CWT06 is 2.5m
current probes
Power input - mechanical - environmental
Power Supply
All CWT units are supplied with four AA Lithium batteries (typical life 90 hours) and a 12V-24Vdc input socket
and a power adapter (AC to 12vDC), to power the CWT from 230Vac or 115 Vac. Specify adapter type 230V or 115V
Rechargeable batteries, option R, are available. (batteries are charged whenever external +12-24V dc supply is present). Typical recharge time 40 hrs, typical life 8 hrs.
H =183mm, W = 93mm, D = 32mm
BNC (output impedance 50 ohms- unit supplied with 0.5m BNC-BNC coaxial cable)
100kohm (for rated accuracy)
0℃ to 40℃
CWT mini unit is supplied with bnc-bnc cable, 12-24Vdc input, 4 AA batteries, power adapter, user manual, calibration certificate and carry case.
Power Option:
Cable length (m) Coil circumference (mm) Insulation (kV)
e.g. order code 30Apk, 4 AA Batteries, ac adapter, 12-24Vdc input, 1metre cable, 100mm coil, 5kV insulation CWT mini 015 B 1 100 5
e.g. order code 6kApk, 4 AA Batteries, ac adapter, 12-24Vdc input, 2.5 metre cable, 200mm coil, 2kV insulation CWT mini 30 B 2.5 200 2
e.g. order code 120Apk, 4 x AA rechargeable Batteries, internal battery charger, ac adapter, 12-24Vdc input, 2.5metre cable, 100mm coil length and 5kV isolation CWT mini 06 R 2.5 100 5

If you have any queries regarding the CWT or require specifications outside our standard ranges please do not hesitate to contact us.