This LED lamp was originally designed for use on a budget solar-charged 12V electrical system. It is bright enough for comfortable reading at night and features constant LED brightness with diminishing battery voltage. The circuit uses six high-brightness white LEDs mounted in a 90mm diameter reflector. The upper half of a stainless steel ice crea
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m bowl makes a good reflector but almost any torch reflector of a similar size will do. As shown, two banks of three series-connected LEDs are powered from a 12V (nominal) DC supply. The LEDs used are rated at 20mA maximum with a measured voltage drop of 3. 2V. Each bank combines an inexpensive LM334 current source IC with a BC558 transistor to provide a constant 20mA to the LED string. Basically, the LM334 controls the base current of the BC558 such that 64mV appears between its "R" and "V-" terminals. With the 3. 3O resistor shown, this results in close to the desired 20mA through the LEDs. The components can be mounted on a small piece of Veroboard. An old desk lamp makes an ideal body, with a metal disc used to cover the hole left after the 240V lamp fitting is removed. The metal disc can also be used to mount the power switch and rubber grommet for the power supply leads. Three M3 screws and nuts spaced 120 ° apart keep the reflector in place.
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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