This power supply circuit is designed around the garden variety 12VAC landscape lighting transformer. Transformer availability and selection has long been a problem for the experimenter, and has often driven them to experiment with dangerous off-line capacitor limited power supplies. However, the long neglected 12V landscape lighting transforme
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r is a good solution due to numerous advantages such as low cost, availability, and power variations (VA ratings). Directly rectifying the 12V transformer secondary is not a good choice because the rectified voltage is generally way high (typically 18VDC) due to peak detection of the sine wave ”in the past, this required a large, inefficient ballast resistor to drop the extra 6V. However, a voltage multiplier (quadrupler) has some very interesting properties ” not only does it increase the voltage substantially, but it offers low voltage regulation that is ideal for powering constant voltage devices such as LEDs. The combination of the 12V lighting transformer and the voltage multiplier is like a match made in heaven. The multiplier delivers 36V (loaded). To accommodate the higher output voltage, (3) 12V LED devices are connected in series to match this voltage. The voltage may be adjusted simply by varying capacitor size. Capacitors are garden variety aluminum electrolytics. The common 3 to 4W LED is bright, but a little low to be useful in general purpose lighting. Connecting (3) in series provides 9 to 12W, a much more useful level of illumination. The 12V LED unit is commonly available due to automotive and 12V battery applications. The initial circuit considered was the classic Cockcroft-Walton multiplier. While it functions, the output current tends to be too limited for this application. Note that all circuits tested...
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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