Page:Elementary lectures on electric discharges, waves and impulses, and other transients (Steinmetz 1911).djvu/22

 that is, $$c$$ is the reciprocal of the projection $$T = \overline{t_1 t_2}$$ on the zero line of the tangent at the starting moment of the transient. that is, the percentual change of current is constant, or in other words, in the same time, the current always decreases by the same fraction of its value, no matter what this value is.

that is, the curve is the exponential.

An instance of the first case is the acceleration or deceleration