Definition
An electronic device with no moving parts that converts direct current (D.C.) from the aircraft battery or generator into alternating current (A.C.) at the voltage and frequency required by certain aircraft instruments and equipment. It uses semiconductor components such as transistors to switch the D.C. supply rapidly, producing an A.C. output — typically 115 volts at 400 hertz for aviation use.
Plain English
A small electronic box that turns the steady D.C. power from the aircraft's battery into the alternating-current power that some instruments need to run. It does this using electronic chips rather than spinning parts.
Context Anchor
Seen in aircraft electrical-system discussions, especially where D.C. aircraft power must supply instruments or equipment that need A.C. power.
Derivation
Solid-state' means the device works through solid semiconductor materials (like silicon chips) rather than moving parts or vacuum tubes. 'Invert' comes from the Latin invertere, meaning 'to turn upside down' — here it captures the idea of flipping one form of electricity (D.C.) into its opposite form (A.C.).
Why Pilots Care
It supplies stable AC power to navigation and communication equipment while avoiding the maintenance and failure risks of older rotary converters.
Analogy
It is like a travel power adapter that changes one kind of electrical power into the kind a device is built to accept. The adapter does not create unlimited power; it only changes the form of the power being supplied.
Intuition Check
“Solid-state” does not mean the unit is simply physically solid. Here it means the inverter uses electronic parts with no moving mechanical parts to change D.C. power into A.C. power.
Example Sentence 1
When the attitude indicator and heading indicator both failed at the same time, the pilot suspected the solid-state D.C. to A.C. inverter rather than the instruments themselves.
Example Sentence 2
During preflight checks the pilot confirms the solid-state inverter is operating before relying on AC-dependent avionics.