While they have been with us for many years, fluorescent lamps remain somewhat mysterious to most people. This isn`t really surprising, since their operation isn`t simple. The tube itself contains a mixture of gases, but the active ingredient is mercury. When operated as an arc, mercury vapour emits a vast amount of short-wave ultraviolet light. T
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his is invisible, but phosphors on the inside of the tube itself fluoresce when struck by UV, and are designed to emit visible light. Most of the remaining UV light is absorbed by the glass, which is opaque to ultraviolet (this is why you can`t get a suntan from behind a glass window). Refer to Figure 1 to follow the explanation. This also shows a representation of the fitting that was used for the illumination tests. For all tests, only the centre tube was installed, with the others removed to ensure that each lamp was operating under near identical conditions. In order to start the arc inside the tube, a starter is used. This is a small neon lamp, with a bimetallic strip contact mechanism built in. When power is first applied, the neon conducts a small current - enough to heat the bimetallic strip, and this causes the switch to close. Once closed, current flows through the filaments at each end of the tube via the ballast, bringing them to working temperature. The ballast limits the current to a safe value. The filaments themselves are fairly rugged, and are typically around 2 Ohms resistance each. While the switch in the starter is closed, there is no current flow through the neon gas in the starter. The bimetal strip cools and the contacts open. When current drawn through an inductor is suddenly interrupted, a high voltage is generated as the magnetic field collapses. This high voltage will (hopefully) strike the arc in...
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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