Zener diodes are designed to operate in the reverse breakdown region of their voltage-current characteristic curve. They are used primarily for voltage regulation and voltage reference applications. When operated in reverse bias beyond their breakdown voltage (known as the Zener voltage), Zener diodes conduct current efficiently, maintaining a nearly constant voltage drop across their terminals. This unique characteristic makes them valuable in voltage regulation circuits, surge protection, and voltage reference circuits. Higher breakdown voltages, power ratings, and current handling capabilities may contribute to higher price points for Zener diodes. When purchasing Zener diodes, consider the specific voltage regulation requirements of your circuit. Determine the desired breakdown voltage range, power dissipation capability, and current ratings needed for your application. Pay attention to parameters such as reverse leakage current, temperature coefficient, and package type suitable for your PCB layout.