A hybrid voltage system is an electric circuit where different voltage subsystems spread out from the power supply

Power supply

A power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...

.

Automobiles

Many hybrid cars use high voltage for the electric motors that use excess electricity from the alternator in idling mode, as well as 12 volts for conventional automobile accessories like headlights, cigarette lighter receptacle for accessories, car audio equipment. And it even uses 5 volts for USB on car audio, or for charging 5 volt devices on USB.

Aviation

Airplanes often have a hybrid 400 volts AC (200 Hz 3-phase) and 28 volt DC (though recent aircraft have adopted 12 volt cigarette lighter receptacles, mains AC plugs (NEMA and others) and 5 volt USB).

Computers

Personal computer

Personal computer

A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s will have power supplies that output 3.3 volts (for CPU power), 5 volts (for computer data buses and secondary drive bay motors, most famously USB

Universal Serial Bus

USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....

 has been widely adopted as a 5 volt power source outside of computing), and 12 volts (for running the disk platter motors on drive bay

Drive bay

A drive bay is a standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed....

 devices like hard disk

Hard disk

A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

s, and optical disc drives).