Neon Bulb Lightening Detector.

 

Lightning Detection

In a thunderstorm, the local electric field can rise from a few tens of volts/meter in fair weather to several thousand volts/meter. Before a lightning strike, the field may change extremely quickly.

Typical simple setup

  1. Aerial: A short whip or wire antenna (sometimes just 1–2 m long).

  2. Coupling network: A high-value resistor (a few megohms.)

  3. Ground return: The other side of the bulb goes to ground.

Operation:

  • A nearby lightning discharge produces a fast transient in the electric field and sometimes a burst of RF energy.

  • The transient can couple into the antenna and momentarily raise the potential across the neon bulb to its striking voltage.

  • The bulb flashes briefly — sometimes visibly flickering more as a storm approaches.

  • Some designs put the bulb in front of a photocell to trigger an alarm.



Atmospheric Electrification Detection (Fair Weather)

The Earth’s atmosphere is always slightly charged — the “fair-weather electric field” is usually ~100 V/m, with the ground negative relative to the ionosphere.

  • With an elevated plate or wire connected through a high-value resistor to a neon bulb, you can watch slow field variations caused by passing clouds, aerosol concentration changes, or distant storm systems.

  • Because a neon bulb’s striking voltage is relatively high (~70 V for a tiny NE-2), you need a capacitive storage scheme (charging a capacitor from the antenna until the bulb fires).

  • This creates a rate meter effect — the time between flashes tells you the field strength.


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