Current Monitor Probes

Current monitor/sensing probes measure superimposed RF currents flowing in conductors or cable harnesses. The primary application is to measure conducted emissions to meet various EMC standards. Common standards that require conducted emissions measurements include CISPR 16-1-2, RTCA DO-160, and MIL-STD-461.

List of current monitoring / sensing probes available from Com-Power:

CLCE-227

The CLCE-227 is a compact split-core RF current probe with a 27 mm aperture, covering the 9 kHz to 230 MHz frequency range. It supports up to 25 A at 400 Hz and offers a nominal transfer impedance of −11 dBΩ (0.28 Ω). This probe is well-suited for conducted emissions measurements as well as RF current monitoring during conducted susceptibility testing (e.g., MIL-STD-461 CS114). Its small form factor makes it ideal for clamping around individual wires or smaller cable bundles without disconnecting connectors. Compliant with CISPR 16-1-2, MIL-STD-461, and RTCA DO-160. Each unit ships with an individual NIST-traceable calibration and a 3-year warranty.

CLCE-332

The CLCE-332 is a split-core ferrite clamp probe covering 9 kHz to 300 MHz with a 32 mm aperture. It handles up to 42 A at 400 Hz, making it suitable for a wide range of cable sizes encountered in standard conducted emission testing. The probe is individually calibrated and supports compliance testing per CISPR 16-1-2, MIL-STD-461, and RTCA DO-160 standards. Includes a 3-year warranty.

CLCE-438

The CLCE-438 offers a broader 9 kHz to 400 MHz frequency range with a larger 38 mm inner diameter. Rated for 30 A at 400 Hz, it is suited for medium-current monitoring in both conducted emission and conducted immunity testing environments. The extended upper frequency limit makes it a versatile choice for applications requiring wider bandwidth coverage. Compliant with CISPR, MIL-STD-461, and RTCA DO-160.

CLCE-1032

Designed for wideband applications up to 1 GHz, the CLCE-1032 shares the compact 32 mm inner diameter with the CLCE-332 but supports significantly heavier currents — up to 135 A at 400 Hz. This combination of high current capacity and ultra-wide frequency coverage (9 kHz–1000 MHz) makes it ideal for high-power cable testing and demanding EMC compliance scenarios. Supports CISPR, MIL-STD-461, and RTCA DO-160.

CLCE-252

The CLCE-252 is designed for high-current applications and features a large 52 mm aperture that accommodates thick cable bundles. It supports up to 200 A at 400 Hz (typical) across a 9 kHz to 230 MHz range, making it an excellent choice for compliance testing where large-diameter harnesses must be measured without disconnection. Compliant with CISPR, MIL-STD-461, and RTCA DO-160.

CLCE-452 V2

The CLCE-452 V2 is an updated version offering a 52 mm aperture and an extended frequency range of 9 kHz to 400 MHz. It handles up to 100 A at 400 Hz (typical), making it suitable for medium- to high-current RF monitoring in both commercial and military EMC testing scenarios. The wider bandwidth combined with the large aperture provides flexibility for a variety of cable types and test setups. Supports CISPR, MIL-STD-461, and RTCA DO-160.

Application of RF Current Probes

RF current probes are employed to monitor or measure asymmetrical disturbance RF currents on a wire, cable, or cable bundle without making direct conductive contact with the source conductor. The current is measured inductively by clamping the probe around the conductor(s) to be tested. No actual contact is made with the conductor(s), and the insulation is left in place. Essentially, a current probe functions as a toroidal transformer where the conductor(s) act as a single-turn primary and the probe as a multiple-turn secondary.

Current Probe Calibration Fixture

Current probes are calibrated through the use of a calibration fixture which provides a 50Ω coaxial-type transmission line arrangement. The fixture allows the probe to be clamped around the center conductor, while the outer conductor encapsulates the probe on four sides so that the transmission line characteristics are not compromised. Refer to the corresponding calibration fixture product page for additional details and ordering information.