Another key feature of the open loop hall effect CS is the ability of the sensor to ‘track’ or ‘follow’ a fast input current waveform. The fastest being a step function with a fast input rise time, or, rate of change of current. The rate of change of current, called di/dt, is the time duration from 10% to 90% of the input signal. Open loop hall effect current sensors are able to ‘respond’ to these high speed signals in less than 5µSec.