State the function of the following diodes.(i) Power diode(ii) Signal diode(iii) Varactor diode(iv) Zener diode

(i) Power Diode: Power diodes are primarily used in conversion and power management applications. They are designed to handle high current and high voltage levels. They are commonly used in power supplies, including converters and inverters, to convert AC voltage into DC voltage.

(ii) Signal Diode: Signal diodes are used for signal conditioning, which includes tasks like amplification, modulation, and demodulation. They are designed to handle low power and are used in circuits where the power level is low, such as in radio frequency (RF) applications.

(iii) Varactor Diode: Varactor diodes are used as voltage-controlled capacitors. The main function of a varactor diode is to change its capacitance value based on the reverse voltage applied across its terminals. They are commonly used in frequency tuning applications, such as in TV sets, FM radios, and cell phones.

(iv) Zener Diode: Zener diodes are used for voltage regulation and voltage reference purposes. They allow current to flow not only from its anode to its cathode like a normal diode, but also in the reverse direction when the voltage is above a certain value known as the Zener voltage. This makes them useful in providing a stable reference voltage in power supply circuits.