Investigating Capacitors - page 4
Keywords: Investigating Capacitors coursework GCSE physics
By slashwk on 23/11/2006 17:28:09
Level: GCSE Key Stage 4 (Years 10-11)
Page Number: 4 of 9 pages: 1 2 3 4 5 6 7 8 9
the flash's capacitor over several seconds, and then the capacitor dumps the full charge into the flash tube almost instantly. This can make a large, charged capacitor extremely dangerous - flash units and TVs have warnings about opening them up for this reason. They contain big capacitors that can, potentially, kill you with the charge they contain.
Capacitors are used in several different ways in electronic circuits:
• Sometimes, capacitors are used to store charge for high-speed use. That's what a flash does. Big lasers use this technique as well to get very bright, instantaneous flashes.
• Capacitors can also eliminate ripples. If a line carrying DC voltage has ripples or spikes in it, a big capacitor can even out the voltage by absorbing the peaks and filling in the valleys.
• A capacitor can block DC voltage. If you hook a small capacitor to a battery, then no current will flow between the poles of the battery once the capacitor charges (which is instantaneous if the capacitor is small). However, any alternating current (AC) signal flows through a capacitor unimpeded. That's because the capacitor will charge and discharge as the alternating current fluctuates, making it appear that the alternating current is flowing.
• One big use of capacitors is to team them up with inductors to create oscillators
Hypothesis
From the research that I have done, I can make a few educated hypothesises.
I can firstly predict that each capacitor will start to charge somewhat rapidly before becoming slower and slower. I believe this because I have understood from my research that electrons move along the wire to the first plate inside a capacitor. With every electron that reaches this plate, the charge of the plate becomes more and more negative and therefore repels electrons away. This is helpful because it also pushes electrons on the second plate away and back to the cell (and therefore creating the illusion of a full circuit), but this is less helpful for those electrons being pushed by the cell in the first place, as they are going to find it increasingly harder to reach the first plate as the electrons which got there first, are pushing them back.
Another hypothesis that I can make from my research information is that because of the effect in my first hypothesis, the capacitor will take a very long time indeed to fully charge. This means that at one point it will look
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