Скачать с ютуб Parasitic Capacitance. Reasons for Occurrence. ... в хорошем качестве

Parasitic Capacitance. Reasons for Occurrence. ...

Parasitic Capacitance. Reasons for Occurrence. Circuit Engineering. Similarly to a regular capacitor formed by two parallel plates, parasitic capacitance occurs every time two conductors are placed next to each other, especially if in parallel, and are not connected to each other or are not separated by a Faraday cage. Parasitic capacitance is generated on a circuit board between the parallel tracks. As a rule, parasitic capacitance is also registered at high frequencies when modeling circuits on a circuit board, and it could cause serious problems with adjustment of the device. A failure of the circuit caused by parasitic capacitance can be exemplified by an increased noise level, or a decrease in the device's frequency range or instability. Strictly speaking, there is no way to eliminate parasitic capacitance entirely. The only real solution is to bring this effect to a minimum. A Faraday cage can serve as one of the ways of decreasing the impact of parasitic capacitance. This device is in fact an earthing lead located between the source of impact and the loop that needs screening. The Faraday cage breaks the connecting electric field, while the noises and pickup current are closed by the cage to the source itself, which prevents them from impacting the total impedance of the circuit. Another example is capacitive coupling in ceramic IC packages. In some packages, the metallized rim has an additional cobalt-nickel shield soldered to it. In the majority of circuits one of the package edges has an earthing terminal, so the shield is earthed. This is not the case for analogous chips that have no earthing terminals, which is why the shield in them is very often suspended with chassis ground. In certain cases, when parasitic capacitance occurs between the IC package leads, the Faraday cage would not expedient. Let's look at an ADC or a DAC converter. Each bus line can effect the analogous converter port through the parasitic capacitance. This leads to digital fronts penetrating the analogous parts, which decreases the converter's performance in general. This problem can however be eliminated entirely by placing a buffer register between the digital bus and the converter. This method can significantly improve the signal-noise ratio of the converter.