This study presents a detailed analysis of a pyroelectric detector based on a lithium niobate (LiNbO₃) crystal for optimizing its performance under different geometrical configurations and electrical load conditions. The effect of varying the pyroelectric disk radius and thickness, as well as the electrical load resistance, on voltage, current, power, and temperature profiles, was thoroughly investigated. Results indicate that larger disk radii (up to 5 mm) enhance voltage and current sensitivity, thereby maximizing power output. However, larger radii also lead to slower temperature decay, highlighting the need for efficient thermal management to prevent structural overheating and maintain long-term functionality. Additionally, increasing the disk thickness from 0.01 mm to 0.04 mm results in substantial improvements in voltage, current, and power, with the most significant changes occurring between 0.01 mm and 0.02 mm. Conversely, thicker disks show better heat dissipation, helping mitigate temperature rise. The analysis of varied electrical load resistances reveals that lower resistances (1 kΩ) generate higher power and voltage outputs, while higher resistances reduce the system’s electrical response. These findings underscore the importance of optimizing both geometrical and electrical parameters to enhance the overall performance and thermal stability of pyroelectric detectors in practical applications. These findings provide valuable insights for optimizing pyroelectric sensor performance through geometric and electrical load adjustments. Future work includes the fabrication of the sensor using the optimized parameters, followed by experimental validation to assess its real-world performance.