Explain state-space representation of electrical circuits.

State-space represents circuits using first-order differential equations in matrix form: dx/dt = Ax + Bu, y = Cx + Du. State variables are typically inductor currents and capacitor voltages (energy storage elements). Benefits include systematic handling of multi-input/multi-output systems, direct computer simulation, and modern control design techniques. State-space reveals all system modes and is superior to transfer functions for coupled or nonlinear systems analysis.