Types of clamp meters

Clamp meters are an electrical test tool that incorporates a basic digital multimeter with a current sensor. Clamps measure current. On the other hand, Probes measure voltage. Having a hinged jaw built into an electrical meter allows the technician to clamp the jaws around a cable, wire, and other points in an electrical system. It measures the current in the circuit without the risk of disconnecting it. Below their plastic moldings, hard jaws contain ferrite iron built to concentrate, measure, and monitor the magnetic field generated by current as it goes through a conductor.

Clamp Meters also known as clamp-on ammeters, have three types of categories.

Current Transformer

A Current Transformer is a type of instrument transformer that is engineered to produce an alternating current in its secondary, which is proportional to the AC current in the primary. This is used when a current or voltage is too high to measure directly. The secondary current is used for measuring instruments or processing in electronic equipment, which needs isolation between primary and secondary circuits.

Hall Effect

Hall Effect clamp meters can measure both ac and dc current up to the kilohertz which is 1000 Hz range. Similar to current transformer types, Hall Effect clamp meters use rigid iron jaws to concentrate the magnetic field that encircles the conductor being measured. Compared to current transformer clamp meters the jaws are not wrapped by copper wires. Instead, the magnetic field produced by the conductor is focused across one or more gaps in the core after the jaws are clamped around the conductor.


Flexible clamp meters evolved from the simple solenoids and were used first during 1912. Compared to the Current Transformer and Hall Effect clamp meter, the flexible clamp meter does not have an iron core. Instead, they use a wound, helix-shaped coil which reacts to the rate change of a conductor’s magnetic field around which they are placed. The faster the change in amplitude, the more voltage generated by a coil. The integrator circuit in the measurement device transforms that output to a signal that’s proportional to the signal in the conductor.

While clamp meters have different types, they all have the same fundamental methodology when making measurements. A conductor is passed through a probe whether it be the hard jaws built into the clamp meter, a flexible coil of clamp accessory, and a vector sum of currents flowing through the conductor is measured by the meter.

Fluke offers 323 clamp meter which is a good basic troubleshooting tool for commercial and residential electricians. It includes True RMS measurements, optimized ergonomics, and a large display for efficient troubleshooting. It’s designed to perform in the toughest environments and provide noise-free, reliable results, so you can trust it to help you confidently diagnose problems almost anywhere. Reach us through https://presidium.ph/product-category/products/fluke-industrial-group-tools/clamp-meters/  to know more about our clamp meter products.

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