A current sensor is a device that detects electric current (AC or DC) in a wire, and generates a signal proportional to it. The generated signal could be analog voltage or current or even digital output. It can be then utilized to display the measured current in an ammeter or can be stored for further analysis in a data acquisition system or can be utilized for control purpose.

The sensed current and the output signal can be:

• Alternating current input,
  • analog output, which duplicates the wave shape of the sensed current.
  • bipolar output, which duplicates the wave shape of the sensed current.
  • unipolar output, which is proportional to the average or RMS value of the sensed current.
• Direct current input,
  • unipolar, with a unipolar output, which duplicates the wave shape of the sensed current
  • digital output, which switches when the sensed current exceeds a certain threshold