Abstract: Initial value is an important factor denoting physical behavior of stored-energy element. Thus the determination of the initial value is also very important for analyzing the dynamic circuit. After introducing the sig- nificance of the research for initial value, this paper describes the initial value of RL normal or morbid circuit by bounded source stimulus amply and thoroughly through analyzing inductor initial current and impulse voltage of five typical RL normal and morbid circuits. Moreover, the significant conclusion is drawn that inductor voltage must be impulse voltage. The solution of inductor initial current for four RL morbid circuits can be gained, namely, suppo- sing voltage is impulse voltage, then it solutes the initial value according to the conservation law of magnetic linkage or the KVL equations of the inductor subnet. It enhances the cognition for RL morbid circuit initial value and tran- sient response in theory, and solves the difficulty of gaining the initial value in RL morbid circuit.

Key words: normal circuit, morbid circuit, bornded sorrrce, initial value