coherer

A scientist adjusts the coherer in his early radio receiver.

Definition

1. Noun:
   • A device for detecting radio waves: A "coherer" is an early form of radio signal detector, consisting of a glass tube filled with metal filings that cohere (stick together) when exposed to electromagnetic waves, thus changing the electrical resistance of the device. It was used in the first practical radio receivers.

Usage Examples

• (The device that detected radio signals.)
• (The physical action that changed the device's conductivity.)

Advanced Usage

• "to tap the coherer": To restore the coherer's sensitivity by mechanically shaking or tapping the tube, breaking the coherence of the filings after a signal was received.
  • After each signal, the operator had to tap the coherer to reset it for the next transmission. (A necessary maintenance step for the device.)

Variants and Related Words

• Cohere (verb): to stick together; to be united.
  • The filings in the coherer cohere when a radio wave passes through. (The filings stick together.)
• Coherer effect (noun): the phenomenon of increased conductivity in metal filings due to radio-frequency radiation.
  • The coherer effect was the basis for early wireless reception. (The scientific principle behind the device.)

Synonyms

• Detector: a device that detects signals or waves (general term).
• Radio detector: a specific term for a device that detects radio waves.

Related Idioms

• "Coherer of ideas": A metaphorical phrase (rare) meaning a person or thing that brings different concepts together.
  • The professor was a coherer of ideas, uniting physics and engineering in his lectures. (A metaphorical use, not a literal device.)