A current sensor, also commonly known as a current transformer or current transformer, is a device that measures the current flowing through a wire by detecting the current using a magnetic field and generating a proportional output. They are used for both AC and DC currents simultaneously. Current sensors enable us to passively measure current without interrupting the circuit in any way. They are placed around the conductor we want to measure.

Current transformers are essential in many applications. For example, they are commonly used for metering to determine the energy usage of different tenants. They can also assist facility management by providing information on how much and when energy is used, in order to reduce costs and improve efficiency.