What is the standard power supply voltage for most aircraft avionics?

The standard power supply voltage for most aircraft avionics is 28 volts DC. This voltage is commonly used because it strikes a balance between providing sufficient power to various electronic systems while also being manageable for weight and efficiency considerations in the aircraft's electrical system.

Using 28 volts DC allows for the operation of avionics equipment that require higher power levels without the drawbacks of using higher voltages, which could complicate the design of wiring and components. Additionally, the aviation industry benefits from standardization, and 28 volts DC has become the norm, simplifying maintenance and replacement of equipment across different aircraft.

In contrast, 12 volts DC, often used in automotive applications, may not provide enough power for the demands of aviation avionics systems. While 24 volts DC is in some use, particularly in certain military aircraft, it is less prevalent than 28 volts DC in commercial aviation. The 48 volts DC option is mostly used in the context of data communication systems or specialized applications and is not standard for avionics power supply needs.