ABSTRACT
There are twomainmethods of drawing transient curves graphically, these being:
(a) the tangent method – this method is shown in Problem 1
(b) the initial slope and three pointmethod, which is shown in Problem 2, and is based on the following properties of a transient exponential curve: (i) for a growth curve, the value of a transient at
a time equal to one time constant is 0.632 of its steady-state value (usually taken as 63 per cent of the steady-state value), at a time equal to two and a half time constants is 0.918 of its steady-state value (usually taken as 92 per cent of its steady-state value) and at a time equal to five time constants is equal to its steady-state value,
(ii) for a decay curve, the value of a transient at a time equal to one time constant is 0.368 of its initial value (usually taken as 37 per cent of its initial value), at a time equal to two and a half time constants is 0.082 of its initial value (usually taken as 8 per cent of its initial value) and at a time equal to five time constants is equal to zero.
