What are the basic types of DC-DC converters?

DC-DC converters change DC voltage levels. Basic types include: Buck (step-down, output < input), Boost (step-up, output > input), Buck-Boost (output can be higher or lower, inverted polarity). Isolated types include: Flyback (buck-boost derived, simple, low power), Forward (buck derived, better regulation), Full-bridge (high power, excellent performance). Non-isolated converters are simpler; isolated provide galvanic isolation for safety or voltage matching. All use switching and energy storage (inductor/capacitor).