Software for simulation-based learning of electronics was implemented to help learners understand complex and abstract concepts through observing external representations and exploring concept models. The software comprises modules for visualization and simulative manipulation. Differences in learning performance of using the learning software either with or without the simulative manipulation module were investigated in 49 college sophomores. The learning performance was higher for learning software utilizing simulative manipulation and visualization yields than for that lacking simulative manipulation, which suggests that learning performance can be enhanced if visualized learning can appropriately integrate simulative manipulation activities. An analysis of the learning process revealed that the use of simulative manipulation activities to verify and clarify the existing knowledge is crucial to improving the learning performance. (Contains 3 tables and 4 figures.)