An Overview of Current Sensors

A current sensor, or current transformer, is a device that is used to measure the current traveling through a wire by applying a magnetic field to detect current and produce a proportional output. These sensors are placed around a conductor and are typically used with AC and DC current. They are beneficial as they allow operators to measure current passively without interfering with the circuit. Additionally, current sensors are essential electrical instruments that can also provide information regarding how much energy is being used by a system to ensure energy-efficiency. In this blog, we will provide an overview of current sensors, their distinguishing characteristics, and how they work.

When current flows through a conductor, a magnetic field is generated and is used to measure current flow. In the case that the sensor is specially designed to measure AC current, inductive technology is used. AC current changes potential, which makes the magnetic field repeatedly collapse and expand. In an AC current sensor, the wire is wrapped around the core. As current flows through the conductor, a proportional current is generated in the wire. The sensor is then able to create an output voltage that a meter can detect and translate into the amount of current traveling through the conductor. Current sensors are either step-up, step-down, or keep the current the same. Sensors that are step-up or step-down are usually referred to as transformers and consist of two coils: a primary winding and secondary winding coil. While current passes through the primary winding, voltage passes through the secondary winding.

DC current sensors work in a similar way, but rely on Hall Effect technology to operate. Moreover, they have the capacity to measure both AC and DC current, and they consist of a core, a signal conditioning circuitry, and a Hall Effect device. The Hall Effect is a phenomenon that was discovered roughly 150 years ago by American physicist, Edwin Hall. It states that, as current travels through a conductor, it creates a magnetic field. If the conductor is positioned within another magnetic field, the magnetic field produced by the electron moving through the conductor will interact with the outside magnetic field. This will result in the electrons moving to one side of the conductor, creating a voltage that is proportional to the amount of current that was running through the conductor, allowing voltage to be measured.

While current transformers and current sensors seem interchangeable, they have major distinguishing characteristics; current transformers step-down current so that it can be safely monitored, whereas current sensors sense and measure current. The following are two examples of each. First, Rogowski coils are thin, flexible current transformers that are easily installed around a conductor and can be snapped closed. Next, split-core current sensors can be opened and wound around a conductor with ease.

If you are in need of Hall Effect magnetic sensors, current sense resistors, transformers, transducers, or other specialized devices, it is important to find a distributor you can trust to provide you with items of the highest caliber. When you find yourself looking for such components, look no further than NSN Components. NSN Components is a premier purchasing platform with an inventory consisting of over 2 billion new, used, obsolete, and hard-to-find parts sourced from nearly 5,000 manufacturers that we trust. Kickoff the purchasing process today by filling out and submitting an RFQ form as provided below. Upon receival of the form, a dedicated representative will reach out to you with a competitive quote in just 15 minutes or less. Thank you for choosing NSN Components for all your operational needs. 

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1. alex marsh
2. Posted on November 8, 2021
3. it hardware

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