The article describes a simple and very cheap to drive white, blue or UV LEDs, used for example in small lamps and testers. The cost of components shall not exceed CZK 10. Converters for white LED has been on the pages of journals described quite enough. When I recently needed a similar drive, I wanted to use the drive transistors . This drive was not the desired range of supply voltages (2 normal cells) very convenient. A solution would be to use a specialized integrated circuit, the drive should not be the cheapest. So I tried some of us published the involvement of simple inverters plus a few others. With no I was not too pleased.
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Some drives have performance more suitable for demonstration purposes only, while others have very little effect. Several authors have vowed to stabilize or reduce the output current. While such a converter from a really nezv?toval voltage LED current, the "stabilization" was due to saturation of the collector current of the transistor or the supersaturation reactor. For more voltage converters, the efficiency rapidly dwindled. So I suggested a simple involvement in two variants, which in Figure 1 The main connection I replaced one resistor and capacitor component values ??optimized. The drive does not stabilize the current, but with two rechargeable batteries power NiCd or NiMH does not matter because the voltage discharge for most of the time do not change. The drive comes in two variants - with and without the rectifier. When experimenting with the traditional components of the more attractive option rectifier. The drive was more effective. The final implementation of the SMD, however, showed relatively large negative resistance of a small Schottky diode (BAS85), while the efficiency of converters with a rectifier was larger, probably due to less parasitic capacities. Efficiency drive can be larger in both cases about 10% using improved coil winding with less resistance. The tests used a cheap miniature axial choke «Pharmaceuticals (in GM for 3 Electronic CZK). LED current can be adjusted by changing resistor R1 (more...
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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