Definition
A transformer placed at the input side of an electronic circuit or stage that couples an incoming AC signal into the circuit while changing its voltage, current, or impedance to a level suitable for the circuit to process. It also provides electrical isolation between the source and the circuit.
Plain English
A small coil-and-core device at the front of an electronic circuit that takes the incoming signal and adjusts its voltage and resistance match so the circuit can use it cleanly, while keeping the two sides electrically separate.
Context Anchor
Seen in aircraft radio, audio, intercom, and other avionics circuit descriptions or troubleshooting information.
Derivation
From Latin 'inputare' roots giving 'input' (what is put in) and 'transformare' meaning 'to change shape.' An input transformer literally changes the shape of the signal being put into the circuit, adjusting it to fit what comes next.
Why Pilots Care
Ensures stable voltage reaches sensitive instruments and radios, preventing failures or inaccurate readings during flight.
Intuition Check
Input does not mean a pilot control input here. It means the electrical signal entering a circuit or device.
Example Sentence 1
The avionics technician traced the radio fault to a failed input transformer in the receiver's first audio stage.
Example Sentence 2
A failing input transformer caused fluctuating power to the navigation radios during the preflight check.