Presented circuit is very simple. With more sampling, I refrained from using the converter and lamp designed for powering three NiCd or NiMH batteries. Because the voltage difference between the battery and the LED is very small, this arrangement is paradoxically more effective than using the drive. If the battery voltage of 3.9 V (battery is discharged from about 10%) and the LED voltage 3.5 V, the electrical energy used by 90%, while the efficiency drive from PE 2 / 2000 is in the best case 80%. Remains to choose how to control the current through LEDs.
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Originally I wanted to stabilize the current circuit, which panned the LED current in a small series resistor Insertion and by deviations from the reference voltage and turning a blind opened the MOSFET. From this project, I eventually withdrew because of this relatively complex circuit would provide little improvement over the simple transistor circuit, which I eventually used. In Figure A current is flowing eight white LEDs, depending on supply voltage. The first curve shows the LED current, depending on the voltage without any current limitation. It's actually voltampere LED characteristics. The figure shows that the characteristics of the knee is not sharp. Diode really begins to shine it at a voltage of about 2.8 V. In the second case, the current limited resistor with resistance 2.7 ohms, and the third transistor with a resistor to the base - see Figure 2 .
Most of the components on a printed circuit board according to Figure 4 and 5 . Outside the plate is only switch S2, which placed it as needed or replace R2 and drop the link. We create the behavior cut into boards for S1. LEDs are soldered to the board stops. Solder pads should be possible Can we shorten the time soldering LEDs to a strict minimum. Instead of engaging temporarily R1 trimmer resistance 5 kOhm resistance (up to 8 LEDs), more preferably in series with a resistor 1 kOhm. The board is designed so that more skilled at it-yourselfer can riveted...
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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