Pyroelectricity and the Peltier-Seebeck effect are related but distinct phenomena. Pyroelectricity involves a single substance generating voltage due to a change in temperature over time, while the Seebeck and Peltier effects occur at the junction of two dissimilar metals, producing voltage from a temperature difference or vice versa. The Seebeck effect is characterized by voltage being a function of the temperature gradient in regular conductors, whereas pyroelectricity is specific to certain ionic crystals. Understanding these differences is crucial for applications in thermoelectric devices and energy harvesting. Both concepts highlight the relationship between temperature differentials and electrical potential.