Well, the analogy helped. As long as my question is vaguely related to capacitors, I don't think the teacher would care if I changed the question I am trying to answer. If the current question is a weird/untestable one, then if you were my age, and were doing a sci fair project on charging capacitors, what question would you have done?

I already made a few suggestions above when I thought you were changing the question.

 

Well, I suppose the null hypothesis will be an if/then. It would appear like so (NOTE: this is an example, not the actual hypothesis) "If these types of capacitors are plugged into a 1.5v source, then the tantalum capacitor would reach maximum charge in the shortest amount of time.)

That may be true. But guessing such small times is hard. If we consider the physical limitations, like length of the wires, soldering of the capacitors and similar, they may have an effect. Also the age of the capacitor and its state if you plan to do this for real.

 

I already made a few suggestions above when I thought you were changing the question.

I remember you mentioning the thermal runway of LEDs. But the previous ones, when we were talking about time constants, you seemed to have an idea of what you thought I had changed it to. Might I ask what the were, or what anyone suggests?

 

Might I ask what the were, or what anyone suggests?

I believe you could, as I noted before, demonstrate that not all capacitors are the same by demonstrating their different ability to filter a high frequency noise signal.

One of the major uses of capacitors is exactly this - they are placed across two voltage poles for the purpose of stabilizing the voltage between those two poles. What professionals know is that electrolytic capacitors are relatively inexpensive for their capacity and work very well for low frequency duty in this role. If you know what a full-wave-rectifier is, you may know that they are usually followed by a large electrolytic capacitor to filter out the relatively low frequency 50-120Hz noise.

A ceramic capacitor would be expensive for such a large capacitance value, but even a small one does a very good job of filtering high frequency noise. Better than the electrolytic would. They are often used one per integrated circuit chip and are called "bypass" capacitors in this role.

Anyway, it's not terribly hard to show this difference if you have a signal generator and an oscilloscope.

 

I remember you mentioning the thermal runway of LEDs. But the previous ones, when we were talking about time constants, you seemed to have an idea of what you thought I had changed it to. Might I ask what the were, or what anyone suggests?

As I said in the earlier post:

In theory you can use any resistor value you want, but in practice there are issues if you go either too big or too small. Too big and the leakage current of the capacitor becomes a problem (and this depends on the type of capacitor) and too small and the finite output impedance of your signal source becomes an issue that can't be ignored. For a 0.47 μF capacitor you have a pretty wide range of reasonable resistor values you can use. You probably start with 1 kΩ which would put your 10%-90% rise time in the 1 ms range. Part of your experiment could be the dependence of the results (or the departure of the observed results from those expected) on the resistance chosen. Pick different types of capacitors and different values (say multiples of 10 over a fair range) and plot the percent deviation of the observed time constant from the observed time constant. Here you have to obvious null hypotheses -- first that there is no deviation at all and second that the deviation is independent of the capacitor type.

So your hypothesis would be that the observed time constant deviates from expected time constant as you change the resistor value -- the null hypothesis being that it doesn't.

Another hypothesis would be that the deviation depends on the type and/or the size of the capacitor -- the null hypothesis being that it doesn't.

 

Say one has a electrolytic, film, tantalum, and ceramic capacitor, each at 10 µf. When plugged into 1.5v source, which one will charge the fastest and why? This is for a hypothesis, so don't drag in ERS's, please.

a small one...………..

 

And how are you going to measure the charge time?

The charge time is approximately = 6 x R x C seconds.

Since R is practically zero, the charge time is almost 0 seconds.
Even if we make R = 0.1 Ω, charge time = 6 x 0.1 x 10μs = 6μs
Do you have equipment to measure 6μs?

I imagine that a 2 plate capacitor would charge quickly
here is a given square patch, the spacing between plates determines value in pF
http://www.saturnpcb.com/pa915/

 

This was a great discussion to read.
I had written an article regarding different types of capacitors. It may be helpful for the readers.