there must b some other reason... because for AC it always
changes from +ve max. to zero and from zero to -ve max. and
with this principle transformer inductor core works with ac
only. So what u indicate by sudden change..
and when the load is switched off, I think it gets infinite
resistance not the zero resistance...
so please clarify..
guess:In this case, the resistance becomes zero Ω as well,
increasing total current to a value of infinity(i=v/r).no
real voltage source could arbitrarily supply a huge
overload current and maintain steady voltage at the same
time.this huge current results in the generation of heat