COMMENT
Since this is an electrode current, positive values of i depolarize the cell
and in the presence of the extracellular mechanism there will be a change
in vext since i is not a transmembrane current but a current injected
directly to the inside of the cell.
ENDCOMMENT

NEURON {
	POINT_PROCESS IRamp
	RANGE del, dur, amp0, amp1, i
	ELECTRODE_CURRENT i
}
UNITS {
	(nA) = (nanoamp)
}

PARAMETER {
	del (ms)
	dur (ms)
	amp0 (nA)
	amp1 (nA)
	t_eff (ms)
}
ASSIGNED { i (nA) }

INITIAL {
	i = 0
}

BREAKPOINT {
	at_time(del)
	at_time(del+dur)

	if (t < del + dur && t >= del) {
		t_eff = t - del
		i = amp0 + ((amp1-amp0)/dur)*t_eff
	}else{
		i = 0
	}
}