Fast, accurate simulation of electronic circuits is essential because it provides the information needed to perform accurate analysis of circuit behavior. SPICE simulators are used to verify that analog and mixed-signal circuits will yield the expected outputs. A schematic netlist file and circuit input values are fed to the SPICE software, which simulates the circuit's behavior for a specified length of time. CircuitLogix allows for the observation of voltage and current levels at any circuit node as they change with frequency and time. It allows for obtaining accurate results even when simulating complex circuits where hierarchical blocks are reused. The CircuitLogix simulation engine is based on Berkeley SPICE, and contains a GUI to make circuit design easier and more efficient.