A box full of Geissler tubes and a Ruhmkorff coil. He said his grandfather built the tubes by blowing the glass around 1900, more than one century ago! He wanted to see if the tube still worked, but a first attempt of powering them with the original Ruhmkorff coil failed. Than, we tried with a CCFL (Cold Cathode Fluorescent Lamp) lamp driver circuit found in an old laptop computer, but this
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failed as well. At that time, we had no idea of the voltage required to strike the tubes and, of course, we didn`t want to break or blow up these precious tubes with too much power. So we decided to buy a brand new Geissler tube (yes, they are still manufactured) and designed a dedicated power supply. A Geissler tube is the ancestor of the modern neon sign tubes commonly used for advertising. Today it`s mainly a decorative glowing object, a scientific curiosity and a nostalgic souvenir of the past. It`s composed by a sealed glass tube of any shape, usually between 10cm and 1m in length. It has two electrodes, one on each end, while the interior is evacuated and filled with a low pressure gas (something like 1mbar). A current flowing from the electrodes through the gas make the gas glow and fluorescent materials used to build the tube glow as well. The gas determines the color of the glow: air will glow bluish, neon will glow red, hydrogen will glow pink, and so on. Some elements are often added to the glass to make it also glow and determine its color: the most common is uranium glass that glows yellow-green. Sometimes Geissler tubes are mounted inside bigger glass tubes filling the space in-between with glowing powders or liquids. Sometimes, special targets can be found inside the tube for some more special effect (see the picture section below ). As common neon tubes, Geissler tubes requires a high striking voltage, and...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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