A current sensor is a device that detects electrical 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:

• AC 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
• DC 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

Technologies

• Hall effect
  Hall effect
  The Hall effect is the production of a voltage difference across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current...
  
   IC
  Integrated circuit
  An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
  
   sensor.
• Transformer
  Transformer
  A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
  
   or Current clamp
  Current clamp
  In electrical and electronic engineering, a current clamp or current probe is an electrical device having two jaws which open to allow clamping around an electrical conductor. This allows properties of the electric current in the conductor to be measured, without having to make physical contact...
  
   meter, (suitable for AC current only).
• Resistor
  Resistor
  A linear resistor is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element.The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's...
  
  , whose voltage is directly proportional to the current through it.
• Fiber optic current sensor, using an interferometer
  Interferometry
  Interferometry refers to a family of techniques in which electromagnetic waves are superimposed in order to extract information about the waves. An instrument used to interfere waves is called an interferometer. Interferometry is an important investigative technique in the fields of astronomy,...
  
   to measure the phase change in the light produced by a magnetic field.
• Rogowski coil
  Rogowski coil
  A Rogowski coil, named after Walter Rogowski, is an electrical device for measuring alternating current or high speed current pulses. It consists of a helical coil of wire with the lead from one end returning through the centre of the coil to the other end, so that both terminals are at the same...
  
  , electrical device for measuring alternating current (AC) or high speed current pulses.

See also

• Current shunt
• List of sensors