Current Sensors

AC Current Sensors (or CTs) are typically used in feedback control circuits, overload sensing, measuring load changes, etc.  A current sensor functions by inducing a proportional current, via a magnetic field, into a secondary winding.  Typically, this is accomplished by coupling the conductor to be measured with a winding (i.e. 100 turns for example wound around a toroidal core).  The wound coil is terminated with a burden resistor placed across it, whereby the voltage is then measured across that resistor.  The sensitivity of the current sensor is controlled by the terminating resistance and by the number of secondary turns.