Spark-gap transmitter

A radio transmitter that uses electrical sparks to excite damped oscillations in a resonant circuit, radiating them as radio waves.

Spark gap: A gap between conductors across which an electric discharge occurs when the voltage exceeds the breakdown threshold. The discharge supplies the abrupt energy pulse that starts each oscillation.
Heinrich Hertz: A German physicist who experimentally demonstrated the existence and properties of electromagnetic waves in the 1880s. His spark oscillators and receivers demonstrated the waves later transmitters exploited.
Continuous-wave transmitter: A radio transmitter that generates a sustained carrier wave rather than separate damped wave trains. Its steady carrier enabled cleaner signaling than repeated spark discharges.
Radio communication: The transmission of information through electromagnetic waves without a physical connecting wire. Spark-gap transmitters helped turn radio waves into a practical communication medium.
LC circuit: An electrical circuit containing an inductor and capacitor that exchanges energy between magnetic and electric fields. Its resonance sets the frequency of the transmitter’s oscillations.
Guglielmo Marconi: An Italian inventor who developed practical wireless telegraphy and helped establish radio communication. His early wireless systems used spark-gap transmitters for long-distance signaling.
Vacuum-tube transmitter: A radio transmitter that uses vacuum tubes to generate or amplify radio-frequency signals. Vacuum-tube designs replaced sparks with controllable oscillations suitable for voice and music.
International Radiotelegraph Convention: An international agreement establishing rules for radiotelegraph communication, first adopted in Berlin in 1906. Its rules addressed interference from spark transmitters and encouraged more selective signaling.
Damped oscillation: An oscillation whose amplitude decreases over time as energy leaves the oscillating system. Each spark produces a wave train that fades as circuit energy is radiated and lost.
Nikola Tesla: A Serbian-American inventor and electrical engineer known for work on alternating-current systems and high-frequency electricity. His high-frequency apparatus contributed to the technologies used in spark transmission.

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