>"The operating principle is simple enough, once the neon is ionised and the device is operating in the breakdown condition, pressure variations in the surround

>"The operating principle is simple enough, once the neon is ionised and the device is operating in the breakdown condition, pressure variations in the surrounding air are conducted through the glass, which causes pressure variations in the neon next to the electrodes. Take the current signal through the lamp and high-pass filter it, and you’ve got yourself a really cheap transducer. What a device!" Now that's interesting enough... but what really blew my mind was the following comment: >"Experienced Experimenter says: They can also detect electromagnetic waves including light and terahertz radiation. They are technically simple but multi-application devices that were primarily used as indicator lights." Now, I don't know if all of that is true or not -- but if it is, it would certainly be interesting to do more research/experimentation -- around this set of ideas...