When a primary voltage(electrical potential) is applied to a primary wire, current flows through the wire and generates an electrostatic field. 

By mounting a Hall Sensor device within this electrostatic field, current is then induced into the sensor material of the device.

This field then acts to induce a secondary current through the material of the Hall substrate material. 

The secondary current flows through an external resistor developing a secondary current into the secondary winding. This secondary current in turn produces a voltage across the wire that is proportional to the current in the primary wire. By placing an amplifier within the Hall Effect transducer, we increase the current by amplifying the signal and converting it into a secondary current(Is).

Therefore, the secondary current(Is) is exactly proportional to the primary current at any time. Output(Vm) is detected measured between the secondary current(Is) and an electrostatic potential developed across a measuring resistor(Rm).

Our Isolation Amplifier Technology Voltage Sensors – iSaST EVS Series begins with an internal resistor network. This network measures DC voltage by directly contacting both the Positive High Voltage(+HT) and the Negative High Voltage(-HT). 

This voltage signal is transmitted to the secondary side of the sensor through an insulated transformer that isolates the Primary High Voltage from the Secondary Low Voltage. The resulting signal is then converted through an amplifier into either a current or a Voltage signal. Therefore, the circuit converts a primary voltage into a secondary current or voltage that is proportional to the input.