The complete picture of the single injection current flow in insulator
s with two sets of traps distributed in energy is given for the situat
ion in which the concentration of the lower trap distribution is large
r than or equal to that of the upper distribution. A new approach for
the solution of the problem is given with the help of regional approxi
mation method. The results are compared with the previously reported e
xperimental work to confirm the correctness of the analysis.