PWM is a highly efficient control scheme used to manipulate the flow of power through various electronic devices. I have seen it most commonly used in switched-mode power supplies, LED dimming circuits, and variable speed motor controls, but there are several more applications. The concept of PWM draws from the most basic elements of a binary system:
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on (1) or off (0). At any given moment, switches are turned on or off depending on the feedback signal from the load receiving power. This process allows power to be taken from the source in doses and supplied to the output such that the output remains relatively constant. Exactly how much power is supplied to the load depends on the duty cycle of the switching system. The duty cycle of a PWM waveform refers to the amount of time relative to an entire switching period that the pulse stays high. It is usually expressed as a percentage or decimal and can vary anywhere between 0% (completely off) to 100% (completely on). Figures 1-3 show some examples of various duty cycles used for voltage regulation and the math explaining how the load sees an average voltage depending on the switching conditions. The figures assume the switches are operating at 50 kHz (being turned on and off 50, 000 times/second). In practice, PWM can be implemented in power supplies if the source power is switched at a sufficiently high frequency such that the output inductor can supply current without letting it fall to zero. Current passing through an inductor cannot change instantaneously which means even if the switch from the source is turned off the inductor current will drop steadily instead of falling to zero immediately. As long as the switch comes back on before the inductor current falls too low to be useful, the load sees a continuous flow of...
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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