Degaussing remanence of toroid

[neazoi]

This article https://meettechniek.info/passive/magnetic-hysteresis.html shows an example of degaussing remanence of a core. It states:
"This degaussing of the core is done with an alternating current with an exponential decreasing of the amplitude in time." https://meettechniek.info/passive/hyst-images/degausing.gif

How can such a waveform be accomplished?

 

[FvM]

Color TVs used to drive the degauss coil of the shadow mask tube by mains voltage, fed though a special double NTC/resistor combination that generated a current waveform similar to that in your link. You might review articles and text books describing the technique.

 

[crutschow]

A voltage step input, such as caused by turning on a switch, into an RC differentiator (HP filter) consisting of a series C followed by an R to ground will give an exponential decay of voltage. That can be amplified to drive an exponential decay of current into the core winding.