One of the difficulties in the design of higher-order tunable bandpass filters is achieving correct tracking of the
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variable resistors in the RC networks. The use of switched capacitor networks can obviate that difficulty, as is shown in this filter. The filter can be divided roughly into two stages: an oscillator that controls the electronic switches arid the four phase-shift networks that provide the filtering proper. The oscillator, based on a 555, generates a pulsating signal whose frequency is adjustable over a wide range: the duty factor varies from 1:10 to 100:1. Electronic switches ESI through ES4 form the variable resistors whose value is dependent on the frequency of the digital signal. The operation of these switches is fairly simple. When they are closed, their resistance is about 60 ; when they are open, it is virtually infinitely high. a switch is closed for, say, 25% of the time, its average resistance is therefore 240 . "Varying the open:closed ratio of each switch varies the equivalent average resistance. The switching rate of the switches must be much greater than the highest audio frequency to prevent audible interference between the audio and the clock signals. The input signal causes a given direct voltage across CI, so the op amp can be operated in a quasisym-metric manner, in spite of the single supply voltage. The direct voltage is removed from the output signal by capacitor C10. The fourth-order filter in the diagram can be used over the entire audio range and it has an amplification of about 40, although this depends to some extent on the clock frequency. The bandwidth depends mainly on the set frequency. The circuit draws a current of not more than 15 mA.
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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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....
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