This optodetector measures the position of the ball by the amount of light transmitted by the infrared LED. This is a linear signal across the small area of the detector - it is not just `on` and `off`. This circuit creates a control signal from the two optodetectors. It finds the difference between the two input voltages and amplifies it to get
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the ball`s position. This stage is often called a comparator. This circuit amplifies the control signal in preparation for the power output transistor. Why do we need this stage at all Because we reduced the whole signal by one-ninth in the speed-plus-position circuit. The point of the perpetual top levitation toy is simply that it continues spinning forever, and the challenge is to understand the driving mechanism. The top is made of plastic, and contains embedded in it a small permanent magnet, oriented perpendicular to the spin axis of the top. The base contains a transistor and a coil with two windings, the assembly being driven by a 9-volt power supply. A schematic of the electrical circuit is shown in the figure. As one pole of the magnet (say the south pole) approaches the coil, a current in induced in winding A, in such a direction as to make the base of the transistor (an NPN) go positive. That makes the emitter-collector current flow through winding B, in the opposite direction to A. The current through B is larger than that of A (due to the amplification of the transistor), so by Lenz`s law the magnet pole will be attracted to the coil. This is a simple magnetic levitator circuit which suspends objects a set distance below an electromagnet. The physics behind it is to simply provide a magnetic force which equal and opposite to the gravitational force on the object. The two forces cancel and the object remains...
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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