This is a typical closed-loop current transducer:
https://docs-emea.rs-online.com/webdocs/12ab/0900766b812ab2f3.pdf
They are current-output devices so you can scale the voltage you need by selecting an appropriate load or opamp feedback resistor, within a reasonable range for the specific device.
"Open loop" types tend to be cheaper but not as accurate; the close loop ones have a coil around the magnetic core that is used to cancel the magnetic field around the main conductor passing through the sensor.
If that's eg. 1000 turns for a single pass through "turn", the sensor output current will be exactly 1/1000th the primary current when the magnetic fields cancel out. The hall sensor only has to detect a precise null rather than be linear over a wide range, as with an open loop one.
For sensing AC input current, current transformers are still widely used.
https://inverterdrive.com/group/Spa...rker-CO500068-590-591-AC-Current-Transformer/
They are also current output, in the inverse ratio of their windings; a 200 turn secondary will give 1/200th the current of a single turn primary.
In electronic systems, they normally go to a bridge rectifier then an appropriate load resistor. The voltage across that resistor is proportional to the instantaneous current, with no extra power supply being needed and the whole thing inherently being isolated.
One thing you must note with a current transformer is the secondary must always be securely wired to a load resistance at all times.
Without a proper connection they try to emulate a tesla coil and produce extremely high voltages, normally destroying their own internal insulation...
Current transformers are also often used to connect directly to a low current ammeter and rated as input
utput current rather than turns ratio.
eg.
https://docs-emea.rs-online.com/webdocs/1499/0900766b81499bbe.pdf
Many sellers have ones with eg. 5A rated output rather than the milliamp range needed for electronic sensing; or you could scale the input and output ratings in proportion - eg. a 200:5 one could be used for 2A sensing with 50mA output.
This is more like the type for use with electronic control systems:
https://www.dhgate.com/product/hwct004-micro-precision-current-transformer/405151777.html