In this chapter we shall examine the major quantities of interest in electrical systems and describe their relationships. Differential calculus aids in understanding instantaneous changes, while integ...In this chapter we shall examine the major quantities of interest in electrical systems and describe their relationships. Differential calculus aids in understanding instantaneous changes, while integral calculus is used for summation and accumulation in circuit analysis. They describe the relationships between variables and their rates of change, providing insights into circuit dynamics in the RC, RL, and RLC circuits.