approximate the growth and decay of current and
voltage in circuits involving L, C and R
where i = instantaneous current in amperes at any
given time (t),
E = potential in volts as designated,
R = circuit resistance in ohms,
C = capacitance in farads,
L = inductance in henrys,
V = steady state potential in volts,
VC = reactive volts across C,
VL = reactive volts across L,
VR = voltage across R,
L/R = time constant of RL circuit in seconds,
t = any given time in seconds after switch
is thrown,
e = a constant, 2.718 (base of the natural
system of logarithms),
Sw = switch
The time constant is defined as the time in seconds
for current or voltage to fall to 1/e or 36.8% of its initial
value or to rise to (1 - 1/e) or approximately 63.2%
of its final value.
charged prior to closing Sw.
