Here is the schematic diagram for a 20 Watt driver. I developed this circuit in 1985, and used it to build a lamp that found much use both as camping light and as emergency light during the then-frequent power outages.
The two transistors work as a push-pull oscillator. To avoid crossover conduction, during operation the bases are self-biased to a slightly negative voltage by the 1R5 resistor. The 220uF capacitor gives strong positive bias during power-up, in order to get the oscillator started. 2k2 resistor's only purpose is discharging the capacitor when the circuit is switched off, so it will restart the next time too!
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I used a ferrite core salvaged from an old 12" black and white TV flyback transformer. I wound the primary and feedback windings on one leg of the core, and the windings going to the tube on the opposite leg. This arrangement is crucial for the circuit to work! The only ballasting action in this circuit is the imperfect magnetic coupling between the primary and secondary coils!
You may be wondering about the "ionization antenna" in the schematic. This is simply a piece of wire that runs along the entire length of the tube. You can stick it there with tape, or you can string it from socket to socket, like I did. Striving for the highest possible efficiency, I came up with the design shown in this schematic diagram. A CMOS hex inverter is used as an oscillator and driver for a MOSFET, which drives a high voltage autotransformer that feeds the fluorescent tube via a ballast capacitor. The circuit is very simple and small, uses just 8 components, yet it is extremely efficient (I could not measure the loss, it seems to be below 3%), and it drives the tube with true AC, despite the simplicity!
The tube filaments are not explicitly heated. On powerup, the gas ionizes from the high voltage alone, and the small discharge that starts has enough anodic heating effect to warm up the filaments. Soon the discharge increases, generates a runaway effect, and less than a second after applying power the tube is fully on, working at the...
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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