Definition of transponder in US English:



  • A device for receiving a radio signal and automatically transmitting a different signal.

    • ‘Jitter is one of the biggest concerns for designers of optical networks, which include optical components such as transmitters, receivers, and transponders.’
    • ‘Most aircraft carry transponders, devices that relay a plane's identification, altitude and speed to ground controllers.’
    • ‘New satellites and spacecraft would carry transponders similar to the devices carried by modern aircraft.’
    • ‘They captured these recruits as they left the hive, attached a radar transponder to them and then tracked their flight paths using harmonic radar.’
    • ‘The line includes power supplies, transmitters, optical amplifiers, digital transponders, return-path receivers, fiber-node platforms and Ethernet access devices.’
    • ‘It will also be ensured that transponders, which signal the plane's whereabouts, cannot be turned off as they were in the planes that were hijacked.’
    • ‘The solution was to surgically implant rice-grain-size radio transponders that passively transmit a serial number when scanned with a portable device.’
    • ‘Some also have transponders which automatically change red traffic lights to green.’
    • ‘The satellite will also return images of earth, and serve as a radio transponder.’
    • ‘Ben glanced down at the transponder signal it was putting out.’
    • ‘His transponder's signal had been coming from a cave in the nearby volcano.’
    • ‘Next, some sharks are outfitted with a ‘pinger,’ a transponder that emits a signal once a minute.’
    • ‘The transponder transmits this coded signal using the tuned circuit.’
    • ‘They were professional, no doubt, if they knew that turning off the radio transponders made the planes invisible to the air controllers, that is not something you pick up in flight sim.’
    • ‘When the driver grabs the door handle a sensor receives a signal from a transponder in the fob, and unlocks the door.’
    • ‘This operates automatically via a transponder that can be carried in the pocket or handbag.’
    • ‘The agency says there is no need at present to dispatch a radio transponder to the asteroid, but adds that it will be keeping a close eye on the rock's progress through the solar system.’
    • ‘Signals made by the transponders when a battery-powered antenna is swept over them enable the scientists to easily find all the research rocks carried downstream.’
    • ‘A transponder on the windshield automatically deducts the fare when a vehicle passes, with a 50 per cent discount for a car with three or more persons.’
    • ‘An unidentified pilot could be no more than a private aviator who unknowingly sends out a wrong signal on his transponder.’


1940s: blend of transmit and respond, + -er.