Aircraft Electrical Systems

Though it is not necessary for flight, the aircraft electrical system remains one of the most important onboard systems. Exactly how critical electricity is for the aircraft depends on the aircraft design. Some airplanes do not have electricity at all, while in commercial aircraft, electricity is used for safety equipment, cockpit instruments, environmental systems, entertainment functions, and more.

The power generated on an aircraft is used to charge a battery and run small electronic devices. Because of this, the aircraft power system is more like that of a car than that in your home. Power used to charge a battery must be direct current (DC). In a home, electricity is more commonly transmitted using alternating current (AC). AC power transmits more volts at a lower amperage, but is not suitable for charging batteries or running sensitive electronics. Direct current system voltages are usually dependent on the size of the battery, the two most common being 14-volt systems which charge 12-volt batteries or 28-volt systems which charge 24-volt batteries.

An aircraft’s electrical system can be divided into four parts: a source of generating electricity, a battery to store the energy, a means of distributing the power, and a device that uses the power. To generate power, most aircraft feature an alternator. The alternator charges the battery to store energy in the event that the alternator fails. Small aircraft use power for a wide range of things such as lights, communications, and navigational equipment.

Another power source for many aircraft electrical systems is a generator. Generators create direct current electricity, but have the disadvantage of needing to constantly spin at a high speed to create power. Because of this, they are not optimal for small aircraft. Generators were heavily-used on older aircraft, and now are more common on jet-powered aircraft. They can also be used as starters. Battery power is used to spin the generator, which begins to turn the engine up for starting. Once the engine is running, the engine spins the generator to create electricity.

In commercial airliners or large turbine aircraft that require a lot of power, the battery power alone is not enough to start an engine. In these cases, jets are frequently equipped with an auxiliary power unit (APU). An APU is like a small turbine engine which runs power generators and creates bleed air. APUs are small enough to be started with batteries, but large enough to create electricity for the plane to use or to recharge the batteries. The bleed air they create is also helpful in starting the main engines.

Another device used to supply electrical power is the ground power unit (GPU). These are used on the tarmac to help aircraft start when their batteries are dead. GPUs are essentially used like jumper cables for planes. In addition to this, they are used to provide electricity to an aircraft without running the engines. Rather than running the engine and burning expensive fuel, if the aircraft is sitting for an extended period, the GPU can provide affordable power. This is especially helpful while the pilots are programming navigational equipment or when the passengers need the air conditioning or heat left on in the cabin.

For all types of aircraft electrical system equipment and much more, look no further than Purchasing Synergy, a trusted supplier of parts for a wide range of industries. We are an online distributor of aircraft parts as well as parts pertaining to the aerospace, civil aviation, defense, electronics, and IT hardware markets. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, call us at 1-714-705-4780 or email us at


February 15, 2023
Semiconductor's Certifications and Memberships
The only independent
distributor with a
  • All parts are stocked in the USA.
  • All parts are shipped from the USA.
  • All shipments must comply with U.S.A export laws.
  • No exceptions.
fallen heroes fund

“We Proudly Support Intrepid Fallen Heroes Fund that serves United States Military Personal experiencing the Invisible Wounds of War : Traumatic Brain Injury (TBI) and Post Traumatic Stress (PTS). Please visit website ( and help in their valiant effort”.

Thank You for Visiting.

We Hope that You Will Visit Us Again the Next Time You Need NSN Parts and Make Us Your Strategic Purchasing Partner.

Request for Quote

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.