Quad comparators, type LM339. A flyback DC converter Done. Buck converter Step-up converter Done. that would consume several comparators and maybe there would be some nice LEDs, too. Then it hit me. A VU meter, big, beautiful, professional! From that moment started mythoughts flowing. Those VU-meter ICs that are sold in every electronics shop Maybe ten LEDs. I wanted more, say.
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40 LEDs a channel! 1 dB apart. That could be something. 40 LEDs each accompanied by a comparator, reference voltages generated by a chain of resistors. Linear meter would have been easy to make, but a real VU meter has to be logarithmic. Maybe the meter could be used as a power meter in a power amplifier. VU meter uses formula 20log(V/V0) and power meter formula 10log(V/V0). A spreadsheet for calculating those resistors, easy. Other electronics would contain an input stage, ideal rectifying and RC circuit for smoothing the signal after rectifying. The hit the next problem: The RC circuit. If the VU meter would go down to -40 dB, it would take a long time the meter to decay after an impulse. I did some calculations and noticed, that if the meter would work satisfyingly at 25 Hz input signal, the time constant of that RC circuit would be very long. Decaying after a loud impulse would take seconds. Unacceptable. Well, I included a sample/hold circuit with a digital control. It works as follows: Ideal rectifying finds peaks from the input signal and collects them into a capacitor. That`s the sample part. Then the charge from the capacitor will be transfered into another capacitor, that holds its voltage constant while the first capacitor is discharged and another peak value is collected into it. The LED bar shows the voltage of the second capacitor all the time. That way when a short peak comes into the meter it will be viewed...
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....
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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....
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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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